* [PATCH v2] Simplify memchr with small constant strings
@ 2022-07-07 16:45 H.J. Lu
2022-07-08 12:54 ` Richard Biener
0 siblings, 1 reply; 5+ messages in thread
From: H.J. Lu @ 2022-07-07 16:45 UTC (permalink / raw)
To: gcc-patches
When memchr is applied on a constant string of no more than the bytes of
a word, simplify memchr by checking each byte in the constant string.
int f (int a)
{
return __builtin_memchr ("AE", a, 2) != 0;
}
is simplified to
int f (int a)
{
return ((char) a == 'A' || (char) a == 'E') != 0;
}
gcc/
PR tree-optimization/103798
* tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
(simplify_builtin_call): Inline memchr with constant strings of
no more than the bytes of a word.
* tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
* tree-ssa-strlen.h (use_in_zero_equality): New.
gcc/testsuite/
PR tree-optimization/103798
* c-c++-common/pr103798-1.c: New test.
* c-c++-common/pr103798-2.c: Likewise.
* c-c++-common/pr103798-3.c: Likewise.
* c-c++-common/pr103798-4.c: Likewise.
* c-c++-common/pr103798-5.c: Likewise.
* c-c++-common/pr103798-6.c: Likewise.
* c-c++-common/pr103798-7.c: Likewise.
* c-c++-common/pr103798-8.c: Likewise.
---
gcc/testsuite/c-c++-common/pr103798-1.c | 28 +++++++++++
gcc/testsuite/c-c++-common/pr103798-2.c | 30 ++++++++++++
gcc/testsuite/c-c++-common/pr103798-3.c | 28 +++++++++++
gcc/testsuite/c-c++-common/pr103798-4.c | 28 +++++++++++
gcc/testsuite/c-c++-common/pr103798-5.c | 26 ++++++++++
gcc/testsuite/c-c++-common/pr103798-6.c | 27 +++++++++++
gcc/testsuite/c-c++-common/pr103798-7.c | 27 +++++++++++
gcc/testsuite/c-c++-common/pr103798-8.c | 27 +++++++++++
gcc/tree-ssa-forwprop.cc | 64 +++++++++++++++++++++++++
gcc/tree-ssa-strlen.cc | 4 +-
gcc/tree-ssa-strlen.h | 2 +
11 files changed, 289 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/pr103798-1.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-2.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-3.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-4.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-5.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-6.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-7.c
create mode 100644 gcc/testsuite/c-c++-common/pr103798-8.c
diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
new file mode 100644
index 00000000000..cd3edf569fc
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-1.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+ return __builtin_memchr ("a", a, 1) == 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+ return a != 'a';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
new file mode 100644
index 00000000000..e7e99c3679e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-2.c
@@ -0,0 +1,30 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+#include <string.h>
+
+__attribute__ ((weak))
+int
+f (int a)
+{
+ return memchr ("aE", a, 2) != NULL;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+ return a == 'a' || a == 'E';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i + 256) != g (i + 256))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
new file mode 100644
index 00000000000..ddcedc7e238
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-3.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+ return __builtin_memchr ("aEgZ", a, 3) == 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+ return a != 'a' && a != 'E' && a != 'g';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
new file mode 100644
index 00000000000..00e8302a833
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-4.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int
+f (char a)
+{
+ return __builtin_memchr ("aEgi", a, 4) != 0;
+}
+
+__attribute__ ((weak))
+int
+g (char a)
+{
+ return a == 'a' || a == 'E' || a == 'g' || a == 'i';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
new file mode 100644
index 00000000000..0d6487a13df
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-5.c
@@ -0,0 +1,26 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+ return __builtin_memchr ("aEgiH", a, 5) == 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+ return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
new file mode 100644
index 00000000000..5ccb5ee66e0
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-6.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+ return __builtin_memchr ("aEgiHx", a, 6) != 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+ return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
+ || a == 'x');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
new file mode 100644
index 00000000000..40fd38257d1
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-7.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(char a)
+{
+ return __builtin_memchr ("aEgiHjZ", a, 7) == 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+ return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
+ && a != 'j' && a != 'Z');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i) != g (i))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
new file mode 100644
index 00000000000..0841b18cea4
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr103798-8.c
@@ -0,0 +1,27 @@
+/* { dg-do run { target int128 } } */
+/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
+
+__attribute__ ((weak))
+int f(int a)
+{
+ return __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
+}
+
+__attribute__ ((weak))
+int g(char a)
+{
+ return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
+ || a == 'x' || a == '1' || a == '9');
+}
+
+int
+main ()
+{
+ for (int i = 0; i < 255; i++)
+ if (f (i + 256) != g (i + 256))
+ __builtin_abort ();
+
+ return 0;
+}
+
+/* { dg-final { scan-assembler-not "memchr" } } */
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 69567ab3275..edd1277c23b 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-dfa.h"
#include "tree-ssa-propagate.h"
#include "tree-ssa-dom.h"
+#include "tree-ssa-strlen.h"
#include "builtins.h"
#include "tree-cfgcleanup.h"
#include "cfganal.h"
@@ -1177,6 +1178,15 @@ constant_pointer_difference (tree p1, tree p2)
memcpy (p, "abcd ", 7);
call if the latter can be stored by pieces during expansion.
+ Optimize
+ memchr ("abcd", a, 4) == 0;
+ or
+ memchr ("abcd", a, 4) != 0;
+ to
+ (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
+ or
+ (a == 'a' || a == 'b' || a == 'c' || a == 'd') != 0
+
Also canonicalize __atomic_fetch_op (p, x, y) op x
to __atomic_op_fetch (p, x, y) or
__atomic_op_fetch (p, x, y) iop x
@@ -1193,8 +1203,62 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
return false;
stmt1 = SSA_NAME_DEF_STMT (vuse);
+ tree res;
+
switch (DECL_FUNCTION_CODE (callee2))
{
+ case BUILT_IN_MEMCHR:
+ if (gimple_call_num_args (stmt2) == 3
+ && (res = gimple_call_lhs (stmt2)) != nullptr
+ && use_in_zero_equality (res) != nullptr
+ && CHAR_BIT == 8
+ && BITS_PER_UNIT == 8)
+ {
+ tree ptr = gimple_call_arg (stmt2, 0);
+ if (TREE_CODE (ptr) != ADDR_EXPR
+ || TREE_CODE (TREE_OPERAND (ptr, 0)) != STRING_CST)
+ break;
+ unsigned HOST_WIDE_INT slen
+ = TREE_STRING_LENGTH (TREE_OPERAND (ptr, 0));
+ /* It must be a non-empty string constant. */
+ if (slen < 2)
+ break;
+ tree size = gimple_call_arg (stmt2, 2);
+ /* Size must be a constant which is <= UNITS_PER_WORD and
+ <= the string length. */
+ if (TREE_CODE (size) != INTEGER_CST
+ || integer_zerop (size)
+ || wi::gtu_p (wi::to_wide (size), UNITS_PER_WORD)
+ || wi::geu_p (wi::to_wide (size), slen))
+ break;
+ tree ch = gimple_call_arg (stmt2, 1);
+ location_t loc = gimple_location (stmt2);
+ if (!useless_type_conversion_p (char_type_node,
+ TREE_TYPE (ch)))
+ ch = fold_convert_loc (loc, char_type_node, ch);
+ const char *p = TREE_STRING_POINTER (TREE_OPERAND (ptr, 0));
+ unsigned int isize = TREE_INT_CST_LOW (size);
+ tree *op = new tree[isize];
+ for (unsigned int i = 0; i < isize; i++)
+ {
+ op[i] = build_int_cst (char_type_node, p[i]);
+ op[i] = fold_build2_loc (loc, EQ_EXPR, boolean_type_node,
+ op[i], ch);
+ }
+ for (unsigned int i = isize - 1; i >= 1; i--)
+ op[i - 1] = fold_convert_loc (loc, boolean_type_node,
+ fold_build2_loc (loc,
+ BIT_IOR_EXPR,
+ boolean_type_node,
+ op[i - 1],
+ op[i]));
+ res = fold_convert_loc (loc, TREE_TYPE (res), op[0]);
+ gimplify_and_update_call_from_tree (gsi_p, res);
+ delete[] op;
+ return true;
+ }
+ break;
+
case BUILT_IN_MEMSET:
if (gimple_call_num_args (stmt2) != 3
|| gimple_call_lhs (stmt2)
diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc
index 7b3e3899ea2..5afbae1b72e 100644
--- a/gcc/tree-ssa-strlen.cc
+++ b/gcc/tree-ssa-strlen.cc
@@ -3913,8 +3913,8 @@ strlen_pass::handle_builtin_memset (bool *zero_write)
nonnull if and only RES is used in such expressions exclusively and
in none other. */
-static gimple *
-use_in_zero_equality (tree res, bool exclusive = true)
+gimple *
+use_in_zero_equality (tree res, bool exclusive)
{
gimple *first_use = NULL;
diff --git a/gcc/tree-ssa-strlen.h b/gcc/tree-ssa-strlen.h
index 8d155450db8..fdb4d9d7783 100644
--- a/gcc/tree-ssa-strlen.h
+++ b/gcc/tree-ssa-strlen.h
@@ -35,6 +35,8 @@ struct c_strlen_data;
extern void get_range_strlen_dynamic (tree, gimple *, c_strlen_data *,
pointer_query &);
+extern gimple *use_in_zero_equality (tree, bool = true);
+
/* APIs internal to strlen pass. Defined in gimple-ssa-sprintf.cc. */
extern bool handle_printf_call (gimple_stmt_iterator *, pointer_query &);
--
2.36.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] Simplify memchr with small constant strings
2022-07-07 16:45 [PATCH v2] Simplify memchr with small constant strings H.J. Lu
@ 2022-07-08 12:54 ` Richard Biener
2022-07-12 16:58 ` H.J. Lu
0 siblings, 1 reply; 5+ messages in thread
From: Richard Biener @ 2022-07-08 12:54 UTC (permalink / raw)
To: H.J. Lu; +Cc: GCC Patches
On Thu, Jul 7, 2022 at 6:45 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> When memchr is applied on a constant string of no more than the bytes of
> a word, simplify memchr by checking each byte in the constant string.
>
> int f (int a)
> {
> return __builtin_memchr ("AE", a, 2) != 0;
> }
>
> is simplified to
>
> int f (int a)
> {
> return ((char) a == 'A' || (char) a == 'E') != 0;
> }
>
> gcc/
>
> PR tree-optimization/103798
> * tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
> (simplify_builtin_call): Inline memchr with constant strings of
> no more than the bytes of a word.
> * tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
> * tree-ssa-strlen.h (use_in_zero_equality): New.
>
> gcc/testsuite/
>
> PR tree-optimization/103798
> * c-c++-common/pr103798-1.c: New test.
> * c-c++-common/pr103798-2.c: Likewise.
> * c-c++-common/pr103798-3.c: Likewise.
> * c-c++-common/pr103798-4.c: Likewise.
> * c-c++-common/pr103798-5.c: Likewise.
> * c-c++-common/pr103798-6.c: Likewise.
> * c-c++-common/pr103798-7.c: Likewise.
> * c-c++-common/pr103798-8.c: Likewise.
> ---
> gcc/testsuite/c-c++-common/pr103798-1.c | 28 +++++++++++
> gcc/testsuite/c-c++-common/pr103798-2.c | 30 ++++++++++++
> gcc/testsuite/c-c++-common/pr103798-3.c | 28 +++++++++++
> gcc/testsuite/c-c++-common/pr103798-4.c | 28 +++++++++++
> gcc/testsuite/c-c++-common/pr103798-5.c | 26 ++++++++++
> gcc/testsuite/c-c++-common/pr103798-6.c | 27 +++++++++++
> gcc/testsuite/c-c++-common/pr103798-7.c | 27 +++++++++++
> gcc/testsuite/c-c++-common/pr103798-8.c | 27 +++++++++++
> gcc/tree-ssa-forwprop.cc | 64 +++++++++++++++++++++++++
> gcc/tree-ssa-strlen.cc | 4 +-
> gcc/tree-ssa-strlen.h | 2 +
> 11 files changed, 289 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-1.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-2.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-3.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-4.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-5.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-6.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-7.c
> create mode 100644 gcc/testsuite/c-c++-common/pr103798-8.c
>
> diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
> new file mode 100644
> index 00000000000..cd3edf569fc
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-1.c
> @@ -0,0 +1,28 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int
> +f (char a)
> +{
> + return __builtin_memchr ("a", a, 1) == 0;
> +}
> +
> +__attribute__ ((weak))
> +int
> +g (char a)
> +{
> + return a != 'a';
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
> new file mode 100644
> index 00000000000..e7e99c3679e
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-2.c
> @@ -0,0 +1,30 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +#include <string.h>
> +
> +__attribute__ ((weak))
> +int
> +f (int a)
> +{
> + return memchr ("aE", a, 2) != NULL;
> +}
> +
> +__attribute__ ((weak))
> +int
> +g (char a)
> +{
> + return a == 'a' || a == 'E';
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i + 256) != g (i + 256))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
> new file mode 100644
> index 00000000000..ddcedc7e238
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-3.c
> @@ -0,0 +1,28 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int
> +f (char a)
> +{
> + return __builtin_memchr ("aEgZ", a, 3) == 0;
> +}
> +
> +__attribute__ ((weak))
> +int
> +g (char a)
> +{
> + return a != 'a' && a != 'E' && a != 'g';
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
> new file mode 100644
> index 00000000000..00e8302a833
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-4.c
> @@ -0,0 +1,28 @@
> +/* { dg-do run } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int
> +f (char a)
> +{
> + return __builtin_memchr ("aEgi", a, 4) != 0;
> +}
> +
> +__attribute__ ((weak))
> +int
> +g (char a)
> +{
> + return a == 'a' || a == 'E' || a == 'g' || a == 'i';
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
> new file mode 100644
> index 00000000000..0d6487a13df
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-5.c
> @@ -0,0 +1,26 @@
> +/* { dg-do run { target int128 } } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int f(char a)
> +{
> + return __builtin_memchr ("aEgiH", a, 5) == 0;
> +}
> +
> +__attribute__ ((weak))
> +int g(char a)
> +{
> + return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
> new file mode 100644
> index 00000000000..5ccb5ee66e0
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-6.c
> @@ -0,0 +1,27 @@
> +/* { dg-do run { target int128 } } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int f(char a)
> +{
> + return __builtin_memchr ("aEgiHx", a, 6) != 0;
> +}
> +
> +__attribute__ ((weak))
> +int g(char a)
> +{
> + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> + || a == 'x');
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
> new file mode 100644
> index 00000000000..40fd38257d1
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-7.c
> @@ -0,0 +1,27 @@
> +/* { dg-do run { target int128 } } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int f(char a)
> +{
> + return __builtin_memchr ("aEgiHjZ", a, 7) == 0;
> +}
> +
> +__attribute__ ((weak))
> +int g(char a)
> +{
> + return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
> + && a != 'j' && a != 'Z');
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i) != g (i))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
> new file mode 100644
> index 00000000000..0841b18cea4
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr103798-8.c
> @@ -0,0 +1,27 @@
> +/* { dg-do run { target int128 } } */
> +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> +
> +__attribute__ ((weak))
> +int f(int a)
> +{
> + return __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
> +}
> +
> +__attribute__ ((weak))
> +int g(char a)
> +{
> + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> + || a == 'x' || a == '1' || a == '9');
> +}
> +
> +int
> +main ()
> +{
> + for (int i = 0; i < 255; i++)
> + if (f (i + 256) != g (i + 256))
> + __builtin_abort ();
> +
> + return 0;
> +}
> +
> +/* { dg-final { scan-assembler-not "memchr" } } */
> diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> index 69567ab3275..edd1277c23b 100644
> --- a/gcc/tree-ssa-forwprop.cc
> +++ b/gcc/tree-ssa-forwprop.cc
> @@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
> #include "tree-dfa.h"
> #include "tree-ssa-propagate.h"
> #include "tree-ssa-dom.h"
> +#include "tree-ssa-strlen.h"
> #include "builtins.h"
> #include "tree-cfgcleanup.h"
> #include "cfganal.h"
> @@ -1177,6 +1178,15 @@ constant_pointer_difference (tree p1, tree p2)
> memcpy (p, "abcd ", 7);
> call if the latter can be stored by pieces during expansion.
>
> + Optimize
> + memchr ("abcd", a, 4) == 0;
> + or
> + memchr ("abcd", a, 4) != 0;
> + to
> + (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
> + or
> + (a == 'a' || a == 'b' || a == 'c' || a == 'd') != 0
> +
> Also canonicalize __atomic_fetch_op (p, x, y) op x
> to __atomic_op_fetch (p, x, y) or
> __atomic_op_fetch (p, x, y) iop x
> @@ -1193,8 +1203,62 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
> return false;
> stmt1 = SSA_NAME_DEF_STMT (vuse);
>
> + tree res;
> +
> switch (DECL_FUNCTION_CODE (callee2))
> {
> + case BUILT_IN_MEMCHR:
> + if (gimple_call_num_args (stmt2) == 3
> + && (res = gimple_call_lhs (stmt2)) != nullptr
> + && use_in_zero_equality (res) != nullptr
> + && CHAR_BIT == 8
> + && BITS_PER_UNIT == 8)
> + {
> + tree ptr = gimple_call_arg (stmt2, 0);
> + if (TREE_CODE (ptr) != ADDR_EXPR
> + || TREE_CODE (TREE_OPERAND (ptr, 0)) != STRING_CST)
> + break;
> + unsigned HOST_WIDE_INT slen
> + = TREE_STRING_LENGTH (TREE_OPERAND (ptr, 0));
> + /* It must be a non-empty string constant. */
> + if (slen < 2)
> + break;
> + tree size = gimple_call_arg (stmt2, 2);
> + /* Size must be a constant which is <= UNITS_PER_WORD and
> + <= the string length. */
> + if (TREE_CODE (size) != INTEGER_CST
> + || integer_zerop (size)
> + || wi::gtu_p (wi::to_wide (size), UNITS_PER_WORD)
> + || wi::geu_p (wi::to_wide (size), slen))
it might be convenient to check tree_fits_uhwi_p (size) and
do unsigned HOST_WIDE_INT sz = tree_to_uhwi (size); instead
of playing with wide-int here.
> + break;
> + tree ch = gimple_call_arg (stmt2, 1);
> + location_t loc = gimple_location (stmt2);
> + if (!useless_type_conversion_p (char_type_node,
> + TREE_TYPE (ch)))
> + ch = fold_convert_loc (loc, char_type_node, ch);
> + const char *p = TREE_STRING_POINTER (TREE_OPERAND (ptr, 0));
> + unsigned int isize = TREE_INT_CST_LOW (size);
> + tree *op = new tree[isize];
> + for (unsigned int i = 0; i < isize; i++)
> + {
> + op[i] = build_int_cst (char_type_node, p[i]);
> + op[i] = fold_build2_loc (loc, EQ_EXPR, boolean_type_node,
> + op[i], ch);
> + }
> + for (unsigned int i = isize - 1; i >= 1; i--)
> + op[i - 1] = fold_convert_loc (loc, boolean_type_node,
> + fold_build2_loc (loc,
> + BIT_IOR_EXPR,
> + boolean_type_node,
> + op[i - 1],
> + op[i]));
> + res = fold_convert_loc (loc, TREE_TYPE (res), op[0]);
> + gimplify_and_update_call_from_tree (gsi_p, res);
my worry about -Os remains, can you please add a check
like optimize_bb_for_speed (gimple_bb (stmt2)) || sz <= 2
(so we allow inline expanding two comparisons when not optimizing
for speed)? For UNITS_PER_WORD == 8 this is possibly a
lot of compares, don't we have some _BY_PIECEs limit we
can use here? There's no COMPARE_RATIO it seems,
not sure what we use there.
Since we only inline expand memchr(..) != 0 we're leaving
'a' != x | 'b' != x | ... optimization to possibly
'ab...' != (x|x<<8|x<<12|...) for followup (I'm quite sure we don't
do anything like that). The x "splat" needs log2 (sz) operations
(but they might be slow?), but in the end it might pay off
for power-of-two (sz) (one could even do this in chunks)?
Anyway, this might be for a followup.
Otherwise it looks OK.
Thanks,
Richard.
> + delete[] op;
> + return true;
> + }
> + break;
> +
> case BUILT_IN_MEMSET:
> if (gimple_call_num_args (stmt2) != 3
> || gimple_call_lhs (stmt2)
> diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc
> index 7b3e3899ea2..5afbae1b72e 100644
> --- a/gcc/tree-ssa-strlen.cc
> +++ b/gcc/tree-ssa-strlen.cc
> @@ -3913,8 +3913,8 @@ strlen_pass::handle_builtin_memset (bool *zero_write)
> nonnull if and only RES is used in such expressions exclusively and
> in none other. */
>
> -static gimple *
> -use_in_zero_equality (tree res, bool exclusive = true)
> +gimple *
> +use_in_zero_equality (tree res, bool exclusive)
> {
> gimple *first_use = NULL;
>
> diff --git a/gcc/tree-ssa-strlen.h b/gcc/tree-ssa-strlen.h
> index 8d155450db8..fdb4d9d7783 100644
> --- a/gcc/tree-ssa-strlen.h
> +++ b/gcc/tree-ssa-strlen.h
> @@ -35,6 +35,8 @@ struct c_strlen_data;
> extern void get_range_strlen_dynamic (tree, gimple *, c_strlen_data *,
> pointer_query &);
>
> +extern gimple *use_in_zero_equality (tree, bool = true);
> +
> /* APIs internal to strlen pass. Defined in gimple-ssa-sprintf.cc. */
> extern bool handle_printf_call (gimple_stmt_iterator *, pointer_query &);
>
> --
> 2.36.1
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] Simplify memchr with small constant strings
2022-07-08 12:54 ` Richard Biener
@ 2022-07-12 16:58 ` H.J. Lu
2022-07-13 12:35 ` Richard Biener
0 siblings, 1 reply; 5+ messages in thread
From: H.J. Lu @ 2022-07-12 16:58 UTC (permalink / raw)
To: Richard Biener; +Cc: GCC Patches
On Fri, Jul 8, 2022 at 5:54 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Thu, Jul 7, 2022 at 6:45 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > When memchr is applied on a constant string of no more than the bytes of
> > a word, simplify memchr by checking each byte in the constant string.
> >
> > int f (int a)
> > {
> > return __builtin_memchr ("AE", a, 2) != 0;
> > }
> >
> > is simplified to
> >
> > int f (int a)
> > {
> > return ((char) a == 'A' || (char) a == 'E') != 0;
> > }
> >
> > gcc/
> >
> > PR tree-optimization/103798
> > * tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
> > (simplify_builtin_call): Inline memchr with constant strings of
> > no more than the bytes of a word.
> > * tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
> > * tree-ssa-strlen.h (use_in_zero_equality): New.
> >
> > gcc/testsuite/
> >
> > PR tree-optimization/103798
> > * c-c++-common/pr103798-1.c: New test.
> > * c-c++-common/pr103798-2.c: Likewise.
> > * c-c++-common/pr103798-3.c: Likewise.
> > * c-c++-common/pr103798-4.c: Likewise.
> > * c-c++-common/pr103798-5.c: Likewise.
> > * c-c++-common/pr103798-6.c: Likewise.
> > * c-c++-common/pr103798-7.c: Likewise.
> > * c-c++-common/pr103798-8.c: Likewise.
> > ---
> > gcc/testsuite/c-c++-common/pr103798-1.c | 28 +++++++++++
> > gcc/testsuite/c-c++-common/pr103798-2.c | 30 ++++++++++++
> > gcc/testsuite/c-c++-common/pr103798-3.c | 28 +++++++++++
> > gcc/testsuite/c-c++-common/pr103798-4.c | 28 +++++++++++
> > gcc/testsuite/c-c++-common/pr103798-5.c | 26 ++++++++++
> > gcc/testsuite/c-c++-common/pr103798-6.c | 27 +++++++++++
> > gcc/testsuite/c-c++-common/pr103798-7.c | 27 +++++++++++
> > gcc/testsuite/c-c++-common/pr103798-8.c | 27 +++++++++++
> > gcc/tree-ssa-forwprop.cc | 64 +++++++++++++++++++++++++
> > gcc/tree-ssa-strlen.cc | 4 +-
> > gcc/tree-ssa-strlen.h | 2 +
> > 11 files changed, 289 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-1.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-2.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-3.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-4.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-5.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-6.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-7.c
> > create mode 100644 gcc/testsuite/c-c++-common/pr103798-8.c
> >
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
> > new file mode 100644
> > index 00000000000..cd3edf569fc
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-1.c
> > @@ -0,0 +1,28 @@
> > +/* { dg-do run } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int
> > +f (char a)
> > +{
> > + return __builtin_memchr ("a", a, 1) == 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int
> > +g (char a)
> > +{
> > + return a != 'a';
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
> > new file mode 100644
> > index 00000000000..e7e99c3679e
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-2.c
> > @@ -0,0 +1,30 @@
> > +/* { dg-do run } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +#include <string.h>
> > +
> > +__attribute__ ((weak))
> > +int
> > +f (int a)
> > +{
> > + return memchr ("aE", a, 2) != NULL;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int
> > +g (char a)
> > +{
> > + return a == 'a' || a == 'E';
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i + 256) != g (i + 256))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
> > new file mode 100644
> > index 00000000000..ddcedc7e238
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-3.c
> > @@ -0,0 +1,28 @@
> > +/* { dg-do run } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int
> > +f (char a)
> > +{
> > + return __builtin_memchr ("aEgZ", a, 3) == 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int
> > +g (char a)
> > +{
> > + return a != 'a' && a != 'E' && a != 'g';
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
> > new file mode 100644
> > index 00000000000..00e8302a833
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-4.c
> > @@ -0,0 +1,28 @@
> > +/* { dg-do run } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int
> > +f (char a)
> > +{
> > + return __builtin_memchr ("aEgi", a, 4) != 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int
> > +g (char a)
> > +{
> > + return a == 'a' || a == 'E' || a == 'g' || a == 'i';
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
> > new file mode 100644
> > index 00000000000..0d6487a13df
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-5.c
> > @@ -0,0 +1,26 @@
> > +/* { dg-do run { target int128 } } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int f(char a)
> > +{
> > + return __builtin_memchr ("aEgiH", a, 5) == 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int g(char a)
> > +{
> > + return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
> > new file mode 100644
> > index 00000000000..5ccb5ee66e0
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-6.c
> > @@ -0,0 +1,27 @@
> > +/* { dg-do run { target int128 } } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int f(char a)
> > +{
> > + return __builtin_memchr ("aEgiHx", a, 6) != 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int g(char a)
> > +{
> > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > + || a == 'x');
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
> > new file mode 100644
> > index 00000000000..40fd38257d1
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-7.c
> > @@ -0,0 +1,27 @@
> > +/* { dg-do run { target int128 } } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int f(char a)
> > +{
> > + return __builtin_memchr ("aEgiHjZ", a, 7) == 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int g(char a)
> > +{
> > + return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
> > + && a != 'j' && a != 'Z');
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i) != g (i))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
> > new file mode 100644
> > index 00000000000..0841b18cea4
> > --- /dev/null
> > +++ b/gcc/testsuite/c-c++-common/pr103798-8.c
> > @@ -0,0 +1,27 @@
> > +/* { dg-do run { target int128 } } */
> > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > +
> > +__attribute__ ((weak))
> > +int f(int a)
> > +{
> > + return __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
> > +}
> > +
> > +__attribute__ ((weak))
> > +int g(char a)
> > +{
> > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > + || a == 'x' || a == '1' || a == '9');
> > +}
> > +
> > +int
> > +main ()
> > +{
> > + for (int i = 0; i < 255; i++)
> > + if (f (i + 256) != g (i + 256))
> > + __builtin_abort ();
> > +
> > + return 0;
> > +}
> > +
> > +/* { dg-final { scan-assembler-not "memchr" } } */
> > diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> > index 69567ab3275..edd1277c23b 100644
> > --- a/gcc/tree-ssa-forwprop.cc
> > +++ b/gcc/tree-ssa-forwprop.cc
> > @@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
> > #include "tree-dfa.h"
> > #include "tree-ssa-propagate.h"
> > #include "tree-ssa-dom.h"
> > +#include "tree-ssa-strlen.h"
> > #include "builtins.h"
> > #include "tree-cfgcleanup.h"
> > #include "cfganal.h"
> > @@ -1177,6 +1178,15 @@ constant_pointer_difference (tree p1, tree p2)
> > memcpy (p, "abcd ", 7);
> > call if the latter can be stored by pieces during expansion.
> >
> > + Optimize
> > + memchr ("abcd", a, 4) == 0;
> > + or
> > + memchr ("abcd", a, 4) != 0;
> > + to
> > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
> > + or
> > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') != 0
> > +
> > Also canonicalize __atomic_fetch_op (p, x, y) op x
> > to __atomic_op_fetch (p, x, y) or
> > __atomic_op_fetch (p, x, y) iop x
> > @@ -1193,8 +1203,62 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
> > return false;
> > stmt1 = SSA_NAME_DEF_STMT (vuse);
> >
> > + tree res;
> > +
> > switch (DECL_FUNCTION_CODE (callee2))
> > {
> > + case BUILT_IN_MEMCHR:
> > + if (gimple_call_num_args (stmt2) == 3
> > + && (res = gimple_call_lhs (stmt2)) != nullptr
> > + && use_in_zero_equality (res) != nullptr
> > + && CHAR_BIT == 8
> > + && BITS_PER_UNIT == 8)
> > + {
> > + tree ptr = gimple_call_arg (stmt2, 0);
> > + if (TREE_CODE (ptr) != ADDR_EXPR
> > + || TREE_CODE (TREE_OPERAND (ptr, 0)) != STRING_CST)
> > + break;
> > + unsigned HOST_WIDE_INT slen
> > + = TREE_STRING_LENGTH (TREE_OPERAND (ptr, 0));
> > + /* It must be a non-empty string constant. */
> > + if (slen < 2)
> > + break;
> > + tree size = gimple_call_arg (stmt2, 2);
> > + /* Size must be a constant which is <= UNITS_PER_WORD and
> > + <= the string length. */
> > + if (TREE_CODE (size) != INTEGER_CST
> > + || integer_zerop (size)
> > + || wi::gtu_p (wi::to_wide (size), UNITS_PER_WORD)
> > + || wi::geu_p (wi::to_wide (size), slen))
>
> it might be convenient to check tree_fits_uhwi_p (size) and
> do unsigned HOST_WIDE_INT sz = tree_to_uhwi (size); instead
> of playing with wide-int here.
Fixed.
> > + break;
> > + tree ch = gimple_call_arg (stmt2, 1);
> > + location_t loc = gimple_location (stmt2);
> > + if (!useless_type_conversion_p (char_type_node,
> > + TREE_TYPE (ch)))
> > + ch = fold_convert_loc (loc, char_type_node, ch);
> > + const char *p = TREE_STRING_POINTER (TREE_OPERAND (ptr, 0));
> > + unsigned int isize = TREE_INT_CST_LOW (size);
> > + tree *op = new tree[isize];
> > + for (unsigned int i = 0; i < isize; i++)
> > + {
> > + op[i] = build_int_cst (char_type_node, p[i]);
> > + op[i] = fold_build2_loc (loc, EQ_EXPR, boolean_type_node,
> > + op[i], ch);
> > + }
> > + for (unsigned int i = isize - 1; i >= 1; i--)
> > + op[i - 1] = fold_convert_loc (loc, boolean_type_node,
> > + fold_build2_loc (loc,
> > + BIT_IOR_EXPR,
> > + boolean_type_node,
> > + op[i - 1],
> > + op[i]));
> > + res = fold_convert_loc (loc, TREE_TYPE (res), op[0]);
> > + gimplify_and_update_call_from_tree (gsi_p, res);
>
> my worry about -Os remains, can you please add a check
> like optimize_bb_for_speed (gimple_bb (stmt2)) || sz <= 2
Fixed.
> (so we allow inline expanding two comparisons when not optimizing
> for speed)? For UNITS_PER_WORD == 8 this is possibly a
> lot of compares, don't we have some _BY_PIECEs limit we
There are a few comparisons. Should I limit it to 4 bytes?
> can use here? There's no COMPARE_RATIO it seems,
> not sure what we use there.
>
> Since we only inline expand memchr(..) != 0 we're leaving
> 'a' != x | 'b' != x | ... optimization to possibly
memchr("abcd", a, 4) == 0 is optimized to
(a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
by this patch.
> 'ab...' != (x|x<<8|x<<12|...) for followup (I'm quite sure we don't
It works only for memchr("aaaa", a, 4) == 0. It is optimized to
x != 'a' by this patch.
Thanks.
> do anything like that). The x "splat" needs log2 (sz) operations
> (but they might be slow?), but in the end it might pay off
> for power-of-two (sz) (one could even do this in chunks)?
> Anyway, this might be for a followup.
>
> Otherwise it looks OK.
>
> Thanks,
> Richard.
>
> > + delete[] op;
> > + return true;
> > + }
> > + break;
> > +
> > case BUILT_IN_MEMSET:
> > if (gimple_call_num_args (stmt2) != 3
> > || gimple_call_lhs (stmt2)
> > diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc
> > index 7b3e3899ea2..5afbae1b72e 100644
> > --- a/gcc/tree-ssa-strlen.cc
> > +++ b/gcc/tree-ssa-strlen.cc
> > @@ -3913,8 +3913,8 @@ strlen_pass::handle_builtin_memset (bool *zero_write)
> > nonnull if and only RES is used in such expressions exclusively and
> > in none other. */
> >
> > -static gimple *
> > -use_in_zero_equality (tree res, bool exclusive = true)
> > +gimple *
> > +use_in_zero_equality (tree res, bool exclusive)
> > {
> > gimple *first_use = NULL;
> >
> > diff --git a/gcc/tree-ssa-strlen.h b/gcc/tree-ssa-strlen.h
> > index 8d155450db8..fdb4d9d7783 100644
> > --- a/gcc/tree-ssa-strlen.h
> > +++ b/gcc/tree-ssa-strlen.h
> > @@ -35,6 +35,8 @@ struct c_strlen_data;
> > extern void get_range_strlen_dynamic (tree, gimple *, c_strlen_data *,
> > pointer_query &);
> >
> > +extern gimple *use_in_zero_equality (tree, bool = true);
> > +
> > /* APIs internal to strlen pass. Defined in gimple-ssa-sprintf.cc. */
> > extern bool handle_printf_call (gimple_stmt_iterator *, pointer_query &);
> >
> > --
> > 2.36.1
> >
--
H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] Simplify memchr with small constant strings
2022-07-12 16:58 ` H.J. Lu
@ 2022-07-13 12:35 ` Richard Biener
2022-07-13 16:51 ` H.J. Lu
0 siblings, 1 reply; 5+ messages in thread
From: Richard Biener @ 2022-07-13 12:35 UTC (permalink / raw)
To: H.J. Lu; +Cc: GCC Patches
On Tue, Jul 12, 2022 at 6:59 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On Fri, Jul 8, 2022 at 5:54 AM Richard Biener
> <richard.guenther@gmail.com> wrote:
> >
> > On Thu, Jul 7, 2022 at 6:45 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > >
> > > When memchr is applied on a constant string of no more than the bytes of
> > > a word, simplify memchr by checking each byte in the constant string.
> > >
> > > int f (int a)
> > > {
> > > return __builtin_memchr ("AE", a, 2) != 0;
> > > }
> > >
> > > is simplified to
> > >
> > > int f (int a)
> > > {
> > > return ((char) a == 'A' || (char) a == 'E') != 0;
> > > }
> > >
> > > gcc/
> > >
> > > PR tree-optimization/103798
> > > * tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
> > > (simplify_builtin_call): Inline memchr with constant strings of
> > > no more than the bytes of a word.
> > > * tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
> > > * tree-ssa-strlen.h (use_in_zero_equality): New.
> > >
> > > gcc/testsuite/
> > >
> > > PR tree-optimization/103798
> > > * c-c++-common/pr103798-1.c: New test.
> > > * c-c++-common/pr103798-2.c: Likewise.
> > > * c-c++-common/pr103798-3.c: Likewise.
> > > * c-c++-common/pr103798-4.c: Likewise.
> > > * c-c++-common/pr103798-5.c: Likewise.
> > > * c-c++-common/pr103798-6.c: Likewise.
> > > * c-c++-common/pr103798-7.c: Likewise.
> > > * c-c++-common/pr103798-8.c: Likewise.
> > > ---
> > > gcc/testsuite/c-c++-common/pr103798-1.c | 28 +++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-2.c | 30 ++++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-3.c | 28 +++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-4.c | 28 +++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-5.c | 26 ++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-6.c | 27 +++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-7.c | 27 +++++++++++
> > > gcc/testsuite/c-c++-common/pr103798-8.c | 27 +++++++++++
> > > gcc/tree-ssa-forwprop.cc | 64 +++++++++++++++++++++++++
> > > gcc/tree-ssa-strlen.cc | 4 +-
> > > gcc/tree-ssa-strlen.h | 2 +
> > > 11 files changed, 289 insertions(+), 2 deletions(-)
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-1.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-2.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-3.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-4.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-5.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-6.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-7.c
> > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-8.c
> > >
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
> > > new file mode 100644
> > > index 00000000000..cd3edf569fc
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-1.c
> > > @@ -0,0 +1,28 @@
> > > +/* { dg-do run } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +f (char a)
> > > +{
> > > + return __builtin_memchr ("a", a, 1) == 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +g (char a)
> > > +{
> > > + return a != 'a';
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
> > > new file mode 100644
> > > index 00000000000..e7e99c3679e
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-2.c
> > > @@ -0,0 +1,30 @@
> > > +/* { dg-do run } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +#include <string.h>
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +f (int a)
> > > +{
> > > + return memchr ("aE", a, 2) != NULL;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +g (char a)
> > > +{
> > > + return a == 'a' || a == 'E';
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i + 256) != g (i + 256))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
> > > new file mode 100644
> > > index 00000000000..ddcedc7e238
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-3.c
> > > @@ -0,0 +1,28 @@
> > > +/* { dg-do run } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +f (char a)
> > > +{
> > > + return __builtin_memchr ("aEgZ", a, 3) == 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +g (char a)
> > > +{
> > > + return a != 'a' && a != 'E' && a != 'g';
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
> > > new file mode 100644
> > > index 00000000000..00e8302a833
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-4.c
> > > @@ -0,0 +1,28 @@
> > > +/* { dg-do run } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +f (char a)
> > > +{
> > > + return __builtin_memchr ("aEgi", a, 4) != 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int
> > > +g (char a)
> > > +{
> > > + return a == 'a' || a == 'E' || a == 'g' || a == 'i';
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
> > > new file mode 100644
> > > index 00000000000..0d6487a13df
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-5.c
> > > @@ -0,0 +1,26 @@
> > > +/* { dg-do run { target int128 } } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int f(char a)
> > > +{
> > > + return __builtin_memchr ("aEgiH", a, 5) == 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int g(char a)
> > > +{
> > > + return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
> > > new file mode 100644
> > > index 00000000000..5ccb5ee66e0
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-6.c
> > > @@ -0,0 +1,27 @@
> > > +/* { dg-do run { target int128 } } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int f(char a)
> > > +{
> > > + return __builtin_memchr ("aEgiHx", a, 6) != 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int g(char a)
> > > +{
> > > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > > + || a == 'x');
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
> > > new file mode 100644
> > > index 00000000000..40fd38257d1
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-7.c
> > > @@ -0,0 +1,27 @@
> > > +/* { dg-do run { target int128 } } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int f(char a)
> > > +{
> > > + return __builtin_memchr ("aEgiHjZ", a, 7) == 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int g(char a)
> > > +{
> > > + return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
> > > + && a != 'j' && a != 'Z');
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i) != g (i))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
> > > new file mode 100644
> > > index 00000000000..0841b18cea4
> > > --- /dev/null
> > > +++ b/gcc/testsuite/c-c++-common/pr103798-8.c
> > > @@ -0,0 +1,27 @@
> > > +/* { dg-do run { target int128 } } */
> > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > +
> > > +__attribute__ ((weak))
> > > +int f(int a)
> > > +{
> > > + return __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
> > > +}
> > > +
> > > +__attribute__ ((weak))
> > > +int g(char a)
> > > +{
> > > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > > + || a == 'x' || a == '1' || a == '9');
> > > +}
> > > +
> > > +int
> > > +main ()
> > > +{
> > > + for (int i = 0; i < 255; i++)
> > > + if (f (i + 256) != g (i + 256))
> > > + __builtin_abort ();
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> > > index 69567ab3275..edd1277c23b 100644
> > > --- a/gcc/tree-ssa-forwprop.cc
> > > +++ b/gcc/tree-ssa-forwprop.cc
> > > @@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
> > > #include "tree-dfa.h"
> > > #include "tree-ssa-propagate.h"
> > > #include "tree-ssa-dom.h"
> > > +#include "tree-ssa-strlen.h"
> > > #include "builtins.h"
> > > #include "tree-cfgcleanup.h"
> > > #include "cfganal.h"
> > > @@ -1177,6 +1178,15 @@ constant_pointer_difference (tree p1, tree p2)
> > > memcpy (p, "abcd ", 7);
> > > call if the latter can be stored by pieces during expansion.
> > >
> > > + Optimize
> > > + memchr ("abcd", a, 4) == 0;
> > > + or
> > > + memchr ("abcd", a, 4) != 0;
> > > + to
> > > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
> > > + or
> > > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') != 0
> > > +
> > > Also canonicalize __atomic_fetch_op (p, x, y) op x
> > > to __atomic_op_fetch (p, x, y) or
> > > __atomic_op_fetch (p, x, y) iop x
> > > @@ -1193,8 +1203,62 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
> > > return false;
> > > stmt1 = SSA_NAME_DEF_STMT (vuse);
> > >
> > > + tree res;
> > > +
> > > switch (DECL_FUNCTION_CODE (callee2))
> > > {
> > > + case BUILT_IN_MEMCHR:
> > > + if (gimple_call_num_args (stmt2) == 3
> > > + && (res = gimple_call_lhs (stmt2)) != nullptr
> > > + && use_in_zero_equality (res) != nullptr
> > > + && CHAR_BIT == 8
> > > + && BITS_PER_UNIT == 8)
> > > + {
> > > + tree ptr = gimple_call_arg (stmt2, 0);
> > > + if (TREE_CODE (ptr) != ADDR_EXPR
> > > + || TREE_CODE (TREE_OPERAND (ptr, 0)) != STRING_CST)
> > > + break;
> > > + unsigned HOST_WIDE_INT slen
> > > + = TREE_STRING_LENGTH (TREE_OPERAND (ptr, 0));
> > > + /* It must be a non-empty string constant. */
> > > + if (slen < 2)
> > > + break;
> > > + tree size = gimple_call_arg (stmt2, 2);
> > > + /* Size must be a constant which is <= UNITS_PER_WORD and
> > > + <= the string length. */
> > > + if (TREE_CODE (size) != INTEGER_CST
> > > + || integer_zerop (size)
> > > + || wi::gtu_p (wi::to_wide (size), UNITS_PER_WORD)
> > > + || wi::geu_p (wi::to_wide (size), slen))
> >
> > it might be convenient to check tree_fits_uhwi_p (size) and
> > do unsigned HOST_WIDE_INT sz = tree_to_uhwi (size); instead
> > of playing with wide-int here.
>
> Fixed.
>
> > > + break;
> > > + tree ch = gimple_call_arg (stmt2, 1);
> > > + location_t loc = gimple_location (stmt2);
> > > + if (!useless_type_conversion_p (char_type_node,
> > > + TREE_TYPE (ch)))
> > > + ch = fold_convert_loc (loc, char_type_node, ch);
> > > + const char *p = TREE_STRING_POINTER (TREE_OPERAND (ptr, 0));
> > > + unsigned int isize = TREE_INT_CST_LOW (size);
> > > + tree *op = new tree[isize];
> > > + for (unsigned int i = 0; i < isize; i++)
> > > + {
> > > + op[i] = build_int_cst (char_type_node, p[i]);
> > > + op[i] = fold_build2_loc (loc, EQ_EXPR, boolean_type_node,
> > > + op[i], ch);
> > > + }
> > > + for (unsigned int i = isize - 1; i >= 1; i--)
> > > + op[i - 1] = fold_convert_loc (loc, boolean_type_node,
> > > + fold_build2_loc (loc,
> > > + BIT_IOR_EXPR,
> > > + boolean_type_node,
> > > + op[i - 1],
> > > + op[i]));
> > > + res = fold_convert_loc (loc, TREE_TYPE (res), op[0]);
> > > + gimplify_and_update_call_from_tree (gsi_p, res);
> >
> > my worry about -Os remains, can you please add a check
> > like optimize_bb_for_speed (gimple_bb (stmt2)) || sz <= 2
>
> Fixed.
>
> > (so we allow inline expanding two comparisons when not optimizing
> > for speed)? For UNITS_PER_WORD == 8 this is possibly a
> > lot of compares, don't we have some _BY_PIECEs limit we
>
> There are a few comparisons. Should I limit it to 4 bytes?
Not sure, if we don't have any existing target configurable limit
then using UNITS_PER_WORD is fine for now I guess.
> > can use here? There's no COMPARE_RATIO it seems,
> > not sure what we use there.
> >
> > Since we only inline expand memchr(..) != 0 we're leaving
> > 'a' != x | 'b' != x | ... optimization to possibly
>
> memchr("abcd", a, 4) == 0 is optimized to
>
> (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
>
> by this patch.
>
> > 'ab...' != (x|x<<8|x<<12|...) for followup (I'm quite sure we don't
>
> It works only for memchr("aaaa", a, 4) == 0. It is optimized to
> x != 'a' by this patch.
Hmm, true ;)
Btw, no updated patch in your mail?
Thanks,
Richard.
>
> Thanks.
>
> > do anything like that). The x "splat" needs log2 (sz) operations
> > (but they might be slow?), but in the end it might pay off
> > for power-of-two (sz) (one could even do this in chunks)?
> > Anyway, this might be for a followup.
> >
> > Otherwise it looks OK.
> >
> > Thanks,
> > Richard.
> >
> > > + delete[] op;
> > > + return true;
> > > + }
> > > + break;
> > > +
> > > case BUILT_IN_MEMSET:
> > > if (gimple_call_num_args (stmt2) != 3
> > > || gimple_call_lhs (stmt2)
> > > diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc
> > > index 7b3e3899ea2..5afbae1b72e 100644
> > > --- a/gcc/tree-ssa-strlen.cc
> > > +++ b/gcc/tree-ssa-strlen.cc
> > > @@ -3913,8 +3913,8 @@ strlen_pass::handle_builtin_memset (bool *zero_write)
> > > nonnull if and only RES is used in such expressions exclusively and
> > > in none other. */
> > >
> > > -static gimple *
> > > -use_in_zero_equality (tree res, bool exclusive = true)
> > > +gimple *
> > > +use_in_zero_equality (tree res, bool exclusive)
> > > {
> > > gimple *first_use = NULL;
> > >
> > > diff --git a/gcc/tree-ssa-strlen.h b/gcc/tree-ssa-strlen.h
> > > index 8d155450db8..fdb4d9d7783 100644
> > > --- a/gcc/tree-ssa-strlen.h
> > > +++ b/gcc/tree-ssa-strlen.h
> > > @@ -35,6 +35,8 @@ struct c_strlen_data;
> > > extern void get_range_strlen_dynamic (tree, gimple *, c_strlen_data *,
> > > pointer_query &);
> > >
> > > +extern gimple *use_in_zero_equality (tree, bool = true);
> > > +
> > > /* APIs internal to strlen pass. Defined in gimple-ssa-sprintf.cc. */
> > > extern bool handle_printf_call (gimple_stmt_iterator *, pointer_query &);
> > >
> > > --
> > > 2.36.1
> > >
>
>
>
> --
> H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] Simplify memchr with small constant strings
2022-07-13 12:35 ` Richard Biener
@ 2022-07-13 16:51 ` H.J. Lu
0 siblings, 0 replies; 5+ messages in thread
From: H.J. Lu @ 2022-07-13 16:51 UTC (permalink / raw)
To: Richard Biener; +Cc: GCC Patches
On Wed, Jul 13, 2022 at 5:35 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Tue, Jul 12, 2022 at 6:59 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> >
> > On Fri, Jul 8, 2022 at 5:54 AM Richard Biener
> > <richard.guenther@gmail.com> wrote:
> > >
> > > On Thu, Jul 7, 2022 at 6:45 PM H.J. Lu <hjl.tools@gmail.com> wrote:
> > > >
> > > > When memchr is applied on a constant string of no more than the bytes of
> > > > a word, simplify memchr by checking each byte in the constant string.
> > > >
> > > > int f (int a)
> > > > {
> > > > return __builtin_memchr ("AE", a, 2) != 0;
> > > > }
> > > >
> > > > is simplified to
> > > >
> > > > int f (int a)
> > > > {
> > > > return ((char) a == 'A' || (char) a == 'E') != 0;
> > > > }
> > > >
> > > > gcc/
> > > >
> > > > PR tree-optimization/103798
> > > > * tree-ssa-forwprop.cc: Include "tree-ssa-strlen.h".
> > > > (simplify_builtin_call): Inline memchr with constant strings of
> > > > no more than the bytes of a word.
> > > > * tree-ssa-strlen.cc (use_in_zero_equality): Make it global.
> > > > * tree-ssa-strlen.h (use_in_zero_equality): New.
> > > >
> > > > gcc/testsuite/
> > > >
> > > > PR tree-optimization/103798
> > > > * c-c++-common/pr103798-1.c: New test.
> > > > * c-c++-common/pr103798-2.c: Likewise.
> > > > * c-c++-common/pr103798-3.c: Likewise.
> > > > * c-c++-common/pr103798-4.c: Likewise.
> > > > * c-c++-common/pr103798-5.c: Likewise.
> > > > * c-c++-common/pr103798-6.c: Likewise.
> > > > * c-c++-common/pr103798-7.c: Likewise.
> > > > * c-c++-common/pr103798-8.c: Likewise.
> > > > ---
> > > > gcc/testsuite/c-c++-common/pr103798-1.c | 28 +++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-2.c | 30 ++++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-3.c | 28 +++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-4.c | 28 +++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-5.c | 26 ++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-6.c | 27 +++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-7.c | 27 +++++++++++
> > > > gcc/testsuite/c-c++-common/pr103798-8.c | 27 +++++++++++
> > > > gcc/tree-ssa-forwprop.cc | 64 +++++++++++++++++++++++++
> > > > gcc/tree-ssa-strlen.cc | 4 +-
> > > > gcc/tree-ssa-strlen.h | 2 +
> > > > 11 files changed, 289 insertions(+), 2 deletions(-)
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-1.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-2.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-3.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-4.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-5.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-6.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-7.c
> > > > create mode 100644 gcc/testsuite/c-c++-common/pr103798-8.c
> > > >
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-1.c b/gcc/testsuite/c-c++-common/pr103798-1.c
> > > > new file mode 100644
> > > > index 00000000000..cd3edf569fc
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-1.c
> > > > @@ -0,0 +1,28 @@
> > > > +/* { dg-do run } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +f (char a)
> > > > +{
> > > > + return __builtin_memchr ("a", a, 1) == 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +g (char a)
> > > > +{
> > > > + return a != 'a';
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-2.c b/gcc/testsuite/c-c++-common/pr103798-2.c
> > > > new file mode 100644
> > > > index 00000000000..e7e99c3679e
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-2.c
> > > > @@ -0,0 +1,30 @@
> > > > +/* { dg-do run } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +#include <string.h>
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +f (int a)
> > > > +{
> > > > + return memchr ("aE", a, 2) != NULL;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +g (char a)
> > > > +{
> > > > + return a == 'a' || a == 'E';
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i + 256) != g (i + 256))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-3.c b/gcc/testsuite/c-c++-common/pr103798-3.c
> > > > new file mode 100644
> > > > index 00000000000..ddcedc7e238
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-3.c
> > > > @@ -0,0 +1,28 @@
> > > > +/* { dg-do run } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +f (char a)
> > > > +{
> > > > + return __builtin_memchr ("aEgZ", a, 3) == 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +g (char a)
> > > > +{
> > > > + return a != 'a' && a != 'E' && a != 'g';
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-4.c b/gcc/testsuite/c-c++-common/pr103798-4.c
> > > > new file mode 100644
> > > > index 00000000000..00e8302a833
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-4.c
> > > > @@ -0,0 +1,28 @@
> > > > +/* { dg-do run } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +f (char a)
> > > > +{
> > > > + return __builtin_memchr ("aEgi", a, 4) != 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int
> > > > +g (char a)
> > > > +{
> > > > + return a == 'a' || a == 'E' || a == 'g' || a == 'i';
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-5.c b/gcc/testsuite/c-c++-common/pr103798-5.c
> > > > new file mode 100644
> > > > index 00000000000..0d6487a13df
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-5.c
> > > > @@ -0,0 +1,26 @@
> > > > +/* { dg-do run { target int128 } } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int f(char a)
> > > > +{
> > > > + return __builtin_memchr ("aEgiH", a, 5) == 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int g(char a)
> > > > +{
> > > > + return a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H';
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-6.c b/gcc/testsuite/c-c++-common/pr103798-6.c
> > > > new file mode 100644
> > > > index 00000000000..5ccb5ee66e0
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-6.c
> > > > @@ -0,0 +1,27 @@
> > > > +/* { dg-do run { target int128 } } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int f(char a)
> > > > +{
> > > > + return __builtin_memchr ("aEgiHx", a, 6) != 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int g(char a)
> > > > +{
> > > > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > > > + || a == 'x');
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-7.c b/gcc/testsuite/c-c++-common/pr103798-7.c
> > > > new file mode 100644
> > > > index 00000000000..40fd38257d1
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-7.c
> > > > @@ -0,0 +1,27 @@
> > > > +/* { dg-do run { target int128 } } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int f(char a)
> > > > +{
> > > > + return __builtin_memchr ("aEgiHjZ", a, 7) == 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int g(char a)
> > > > +{
> > > > + return (a != 'a' && a != 'E' && a != 'g' && a != 'i' && a != 'H'
> > > > + && a != 'j' && a != 'Z');
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i) != g (i))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/testsuite/c-c++-common/pr103798-8.c b/gcc/testsuite/c-c++-common/pr103798-8.c
> > > > new file mode 100644
> > > > index 00000000000..0841b18cea4
> > > > --- /dev/null
> > > > +++ b/gcc/testsuite/c-c++-common/pr103798-8.c
> > > > @@ -0,0 +1,27 @@
> > > > +/* { dg-do run { target int128 } } */
> > > > +/* { dg-options "-O2 -fdump-tree-optimized -save-temps" } */
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int f(int a)
> > > > +{
> > > > + return __builtin_memchr ("aEgiHx19ABC", a, 8) != 0;
> > > > +}
> > > > +
> > > > +__attribute__ ((weak))
> > > > +int g(char a)
> > > > +{
> > > > + return (a == 'a' || a == 'E' || a == 'g' || a == 'i' || a == 'H'
> > > > + || a == 'x' || a == '1' || a == '9');
> > > > +}
> > > > +
> > > > +int
> > > > +main ()
> > > > +{
> > > > + for (int i = 0; i < 255; i++)
> > > > + if (f (i + 256) != g (i + 256))
> > > > + __builtin_abort ();
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +/* { dg-final { scan-assembler-not "memchr" } } */
> > > > diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> > > > index 69567ab3275..edd1277c23b 100644
> > > > --- a/gcc/tree-ssa-forwprop.cc
> > > > +++ b/gcc/tree-ssa-forwprop.cc
> > > > @@ -42,6 +42,7 @@ along with GCC; see the file COPYING3. If not see
> > > > #include "tree-dfa.h"
> > > > #include "tree-ssa-propagate.h"
> > > > #include "tree-ssa-dom.h"
> > > > +#include "tree-ssa-strlen.h"
> > > > #include "builtins.h"
> > > > #include "tree-cfgcleanup.h"
> > > > #include "cfganal.h"
> > > > @@ -1177,6 +1178,15 @@ constant_pointer_difference (tree p1, tree p2)
> > > > memcpy (p, "abcd ", 7);
> > > > call if the latter can be stored by pieces during expansion.
> > > >
> > > > + Optimize
> > > > + memchr ("abcd", a, 4) == 0;
> > > > + or
> > > > + memchr ("abcd", a, 4) != 0;
> > > > + to
> > > > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
> > > > + or
> > > > + (a == 'a' || a == 'b' || a == 'c' || a == 'd') != 0
> > > > +
> > > > Also canonicalize __atomic_fetch_op (p, x, y) op x
> > > > to __atomic_op_fetch (p, x, y) or
> > > > __atomic_op_fetch (p, x, y) iop x
> > > > @@ -1193,8 +1203,62 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
> > > > return false;
> > > > stmt1 = SSA_NAME_DEF_STMT (vuse);
> > > >
> > > > + tree res;
> > > > +
> > > > switch (DECL_FUNCTION_CODE (callee2))
> > > > {
> > > > + case BUILT_IN_MEMCHR:
> > > > + if (gimple_call_num_args (stmt2) == 3
> > > > + && (res = gimple_call_lhs (stmt2)) != nullptr
> > > > + && use_in_zero_equality (res) != nullptr
> > > > + && CHAR_BIT == 8
> > > > + && BITS_PER_UNIT == 8)
> > > > + {
> > > > + tree ptr = gimple_call_arg (stmt2, 0);
> > > > + if (TREE_CODE (ptr) != ADDR_EXPR
> > > > + || TREE_CODE (TREE_OPERAND (ptr, 0)) != STRING_CST)
> > > > + break;
> > > > + unsigned HOST_WIDE_INT slen
> > > > + = TREE_STRING_LENGTH (TREE_OPERAND (ptr, 0));
> > > > + /* It must be a non-empty string constant. */
> > > > + if (slen < 2)
> > > > + break;
> > > > + tree size = gimple_call_arg (stmt2, 2);
> > > > + /* Size must be a constant which is <= UNITS_PER_WORD and
> > > > + <= the string length. */
> > > > + if (TREE_CODE (size) != INTEGER_CST
> > > > + || integer_zerop (size)
> > > > + || wi::gtu_p (wi::to_wide (size), UNITS_PER_WORD)
> > > > + || wi::geu_p (wi::to_wide (size), slen))
> > >
> > > it might be convenient to check tree_fits_uhwi_p (size) and
> > > do unsigned HOST_WIDE_INT sz = tree_to_uhwi (size); instead
> > > of playing with wide-int here.
> >
> > Fixed.
> >
> > > > + break;
> > > > + tree ch = gimple_call_arg (stmt2, 1);
> > > > + location_t loc = gimple_location (stmt2);
> > > > + if (!useless_type_conversion_p (char_type_node,
> > > > + TREE_TYPE (ch)))
> > > > + ch = fold_convert_loc (loc, char_type_node, ch);
> > > > + const char *p = TREE_STRING_POINTER (TREE_OPERAND (ptr, 0));
> > > > + unsigned int isize = TREE_INT_CST_LOW (size);
> > > > + tree *op = new tree[isize];
> > > > + for (unsigned int i = 0; i < isize; i++)
> > > > + {
> > > > + op[i] = build_int_cst (char_type_node, p[i]);
> > > > + op[i] = fold_build2_loc (loc, EQ_EXPR, boolean_type_node,
> > > > + op[i], ch);
> > > > + }
> > > > + for (unsigned int i = isize - 1; i >= 1; i--)
> > > > + op[i - 1] = fold_convert_loc (loc, boolean_type_node,
> > > > + fold_build2_loc (loc,
> > > > + BIT_IOR_EXPR,
> > > > + boolean_type_node,
> > > > + op[i - 1],
> > > > + op[i]));
> > > > + res = fold_convert_loc (loc, TREE_TYPE (res), op[0]);
> > > > + gimplify_and_update_call_from_tree (gsi_p, res);
> > >
> > > my worry about -Os remains, can you please add a check
> > > like optimize_bb_for_speed (gimple_bb (stmt2)) || sz <= 2
> >
> > Fixed.
> >
> > > (so we allow inline expanding two comparisons when not optimizing
> > > for speed)? For UNITS_PER_WORD == 8 this is possibly a
> > > lot of compares, don't we have some _BY_PIECEs limit we
> >
> > There are a few comparisons. Should I limit it to 4 bytes?
>
> Not sure, if we don't have any existing target configurable limit
> then using UNITS_PER_WORD is fine for now I guess.
>
> > > can use here? There's no COMPARE_RATIO it seems,
> > > not sure what we use there.
> > >
> > > Since we only inline expand memchr(..) != 0 we're leaving
> > > 'a' != x | 'b' != x | ... optimization to possibly
> >
> > memchr("abcd", a, 4) == 0 is optimized to
> >
> > (a == 'a' || a == 'b' || a == 'c' || a == 'd') == 0
> >
> > by this patch.
> >
> > > 'ab...' != (x|x<<8|x<<12|...) for followup (I'm quite sure we don't
> >
> > It works only for memchr("aaaa", a, 4) == 0. It is optimized to
> > x != 'a' by this patch.
>
> Hmm, true ;)
>
> Btw, no updated patch in your mail?
Here is the v3 patch:
https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598362.html
Thanks.
> Thanks
> Richard.
>
> >
> > Thanks.
> >
> > > do anything like that). The x "splat" needs log2 (sz) operations
> > > (but they might be slow?), but in the end it might pay off
> > > for power-of-two (sz) (one could even do this in chunks)?
> > > Anyway, this might be for a followup.
> > >
> > > Otherwise it looks OK.
> > >
> > > Thanks,
> > > Richard.
> > >
> > > > + delete[] op;
> > > > + return true;
> > > > + }
> > > > + break;
> > > > +
> > > > case BUILT_IN_MEMSET:
> > > > if (gimple_call_num_args (stmt2) != 3
> > > > || gimple_call_lhs (stmt2)
> > > > diff --git a/gcc/tree-ssa-strlen.cc b/gcc/tree-ssa-strlen.cc
> > > > index 7b3e3899ea2..5afbae1b72e 100644
> > > > --- a/gcc/tree-ssa-strlen.cc
> > > > +++ b/gcc/tree-ssa-strlen.cc
> > > > @@ -3913,8 +3913,8 @@ strlen_pass::handle_builtin_memset (bool *zero_write)
> > > > nonnull if and only RES is used in such expressions exclusively and
> > > > in none other. */
> > > >
> > > > -static gimple *
> > > > -use_in_zero_equality (tree res, bool exclusive = true)
> > > > +gimple *
> > > > +use_in_zero_equality (tree res, bool exclusive)
> > > > {
> > > > gimple *first_use = NULL;
> > > >
> > > > diff --git a/gcc/tree-ssa-strlen.h b/gcc/tree-ssa-strlen.h
> > > > index 8d155450db8..fdb4d9d7783 100644
> > > > --- a/gcc/tree-ssa-strlen.h
> > > > +++ b/gcc/tree-ssa-strlen.h
> > > > @@ -35,6 +35,8 @@ struct c_strlen_data;
> > > > extern void get_range_strlen_dynamic (tree, gimple *, c_strlen_data *,
> > > > pointer_query &);
> > > >
> > > > +extern gimple *use_in_zero_equality (tree, bool = true);
> > > > +
> > > > /* APIs internal to strlen pass. Defined in gimple-ssa-sprintf.cc. */
> > > > extern bool handle_printf_call (gimple_stmt_iterator *, pointer_query &);
> > > >
> > > > --
> > > > 2.36.1
> > > >
> >
> >
> >
> > --
> > H.J.
--
H.J.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-07-13 16:52 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-07-07 16:45 [PATCH v2] Simplify memchr with small constant strings H.J. Lu
2022-07-08 12:54 ` Richard Biener
2022-07-12 16:58 ` H.J. Lu
2022-07-13 12:35 ` Richard Biener
2022-07-13 16:51 ` H.J. Lu
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