* [PATCH] Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part
@ 2023-07-12 16:08 Andrew Pinski
2023-07-13 7:38 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Pinski @ 2023-07-12 16:08 UTC (permalink / raw)
To: gcc-patches; +Cc: Andrew Pinski
This fixes part of PR 110293, for the outer comparison case
being `!=` or `==`. In turn PR 110539 is able to be optimized
again as the if statement for `(a&1) == ((a & 1) != 0)` gets optimized
to `false` early enough to allow FRE/DOM to do a CSE for memory store/load.
OK? Bootstrapped and tested on x86_64-linux with no regressions.
gcc/ChangeLog:
PR tree-optimization/110293
PR tree-optimization/110539
* match.pd: Expand the `x != (typeof x)(x == 0)`
pattern to handle where the inner and outer comparsions
are either `!=` or `==` and handle other constants
than 0.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/pr110293-1.c: New test.
* gcc.dg/tree-ssa/pr110539-1.c: New test.
* gcc.dg/tree-ssa/pr110539-2.c: New test.
* gcc.dg/tree-ssa/pr110539-3.c: New test.
* gcc.dg/tree-ssa/pr110539-4.c: New test.
---
gcc/match.pd | 39 ++++++++--
gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c | 58 +++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c | 12 ++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c | 12 ++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c | 75 ++++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c | 82 ++++++++++++++++++++++
6 files changed, 274 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 8543f777a28..351d9285e92 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6429,10 +6429,41 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (TYPE_UNSIGNED (TREE_TYPE (@0)))
{ constant_boolean_node (false, type); }))
-/* x != (typeof x)(x == 0) is always true. */
-(simplify
- (ne:c @0 (convert (eq @0 integer_zerop)))
- { constant_boolean_node (true, type); })
+/* x != (typeof x)(x == CST) -> CST == 0 ? 1 : (CST == 1 ? (x!=0&&x!=1) : x != 0) */
+/* x != (typeof x)(x != CST) -> CST == 1 ? 1 : (CST == 0 ? (x!=0&&x!=1) : x != 1) */
+/* x == (typeof x)(x == CST) -> CST == 0 ? 0 : (CST == 1 ? (x==0||x==1) : x != 0) */
+/* x == (typeof x)(x != CST) -> CST == 1 ? 0 : (CST == 0 ? (x==0||x==1) : x != 1) */
+(for outer (ne eq)
+ (for inner (ne eq)
+ (simplify
+ (outer:c @0 (convert (inner @0 INTEGER_CST@1)))
+ (with {
+ bool cst1 = integer_onep (@1);
+ bool cst0 = integer_zerop (@1);
+ bool innereq = inner == EQ_EXPR;
+ bool outereq = outer == EQ_EXPR;
+ }
+ (switch
+ (if (innereq ? cst0 : cst1)
+ { constant_boolean_node (!outereq, type); })
+ (if (innereq ? cst1 : cst0)
+ (with {
+ tree utype = unsigned_type_for (TREE_TYPE (@0));
+ tree ucst1 = build_one_cst (utype);
+ }
+ (if (!outereq)
+ (gt (convert:utype @0) { ucst1; })
+ (le (convert:utype @0) { ucst1; })
+ )
+ )
+ )
+ (if (innereq)
+ (ne @0 { build_zero_cst (TREE_TYPE (@0)); }))
+ (ne @0 { build_one_cst (TREE_TYPE (@0)); }))
+ )
+ )
+ )
+)
(for cmp (unordered ordered unlt unle ungt unge uneq ltgt)
/* If the second operand is NaN, the result is constant. */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
new file mode 100644
index 00000000000..24aea1a2d03
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
@@ -0,0 +1,58 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized-raw" } */
+
+_Bool eqeq0(unsigned x)
+{
+ return x == (x == 0);
+}
+_Bool eqeq1(unsigned x)
+{
+ return x == (x == 1);
+}
+_Bool eqeq2(unsigned x)
+{
+ return x == (x == 2);
+}
+
+_Bool neeq0(unsigned x)
+{
+ return x != (x == 0);
+}
+_Bool neeq1(unsigned x)
+{
+ return x != (x == 1);
+}
+_Bool neeq2(unsigned x)
+{
+ return x != (x == 2);
+}
+
+_Bool eqne0(unsigned x)
+{
+ return x == (x != 0);
+}
+_Bool eqne1(unsigned x)
+{
+ return x == (x != 1);
+}
+_Bool eqne2(unsigned x)
+{
+ return x == (x != 2);
+}
+
+_Bool nene0(unsigned x)
+{
+ return x != (x != 0);
+}
+_Bool nene1(unsigned x)
+{
+ return x != (x != 1);
+}
+_Bool nene2(unsigned x)
+{
+ return x != (x != 2);
+}
+
+/* All of these functions should have removed the inner most comparison which
+ means all of the conversions from bool to unsigned should have been removed too. */
+/* { dg-final { scan-tree-dump-not "nop_expr," "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
new file mode 100644
index 00000000000..6ba864cdd13
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+int f(int a)
+{
+ int b = a & 1;
+ int c = b != 0;
+ return c == b;
+}
+
+/* This should be optimized to just return 1; */
+/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
+/* { dg-final { scan-tree-dump "return 1;" "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
new file mode 100644
index 00000000000..17874d349ef
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+int f(int a)
+{
+ int b = a & 1;
+ int c = b == 0;
+ return c == b;
+}
+
+/* This should be optimized to just return 0; */
+/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
+/* { dg-final { scan-tree-dump "return 0;" "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
new file mode 100644
index 00000000000..e2bd4dfb45d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
@@ -0,0 +1,75 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void foo(void);
+static int a, c = 1;
+static short b;
+static int *d = &c, *e = &a;
+static int **f = &d;
+void __assert_fail() __attribute__((__noreturn__));
+static void g(short h) {
+ if (*d)
+ ;
+ else {
+ if (e) __assert_fail();
+ if (a) {
+ __builtin_unreachable();
+ } else
+ __assert_fail();
+ }
+ if ((((0, 0) || h) == h) + b) *f = 0;
+}
+int main() {
+ int i = 0 != 10 & a;
+ g(i);
+ *e = 9;
+ e = 0;
+ if (d == 0)
+ ;
+ else
+ foo();
+ ;
+}
+/* The call to foo should be optimized away. */
+/* The missed optimization at -O2 here was:
+ int b = a & 1;
+ int c = b != 0;
+ int d = c == b;
+ not being optimized to 1 early enough, it is done in vrp2 but
+ that is too late.
+ In phiopt2 we got:
+ _17 = i_7 != 0;
+ _12 = (int) _17;
+ if (i_7 == _12)
+ goto <bb 9>; [50.00%]
+ else
+ goto <bb 10>; [50.00%]
+
+ <bb 9> [local count: 268435456]:
+ d = 0B;
+
+ <bb 10> [local count: 536870913]:
+ e.1_3 = e;
+ *e.1_3 = 9;
+ e = 0B;
+ d.2_4 = d;
+ if (d.2_4 == 0B)
+
+ The first if is not optimized before, until vrp2 which is
+ too late as there are no passes which will then find the
+ load of d in `d.2_4 = d;` was `0B` after vrp2.
+
+ Now in forwprop3 (after phiopt2), we optimize:
+ _17 = i_7 != 0;
+ _12 = (int) _17;
+ if (i_7 == _12)
+ into just:
+ _t = (unsigned)i_7;
+ if (_t <= 1)
+
+ And then during ccp3, that is optimized away and that is optimized
+ early enough now that the load `d.2_4 = d;` is optimizd to just
+ `d.2_4 = 0B;`
+ */
+
+/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
new file mode 100644
index 00000000000..2c03dcc87fa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
@@ -0,0 +1,82 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fstrict-aliasing -fdump-tree-optimized" } */
+
+/* This is a small variant of pr110539-3.c using -O1 -fstrict-aliasing
+ rather than -O2. Just to show VRP and PRE is not needed to optimize
+ the call to foo away. */
+
+
+void foo(void);
+static int a, c = 1;
+static short b;
+static int *d = &c, *e = &a;
+static int **f = &d;
+void __assert_fail() __attribute__((__noreturn__));
+static void g(int h) {
+ if (*d)
+ ;
+ else {
+ if (e) __assert_fail();
+ if (a) {
+ __builtin_unreachable();
+ } else
+ __assert_fail();
+ }
+ if (((h!=0) == h) + b) *f = 0;
+}
+
+int main() {
+ int i = 0 != 10 & a;
+ g(i);
+ *e = 9;
+ e = 0;
+ if (d == 0)
+ ;
+ else
+ foo();
+ ;
+}
+
+/* The call to foo should be optimized away. */
+/* The missed optimization at -O1 here was:
+ int b = a & 1;
+ int c = b != 0;
+ int d = c == b;
+ not being optimized to 1 early enough, it is done in vrp2 but
+ that is too late.
+ In phiopt2 we got:
+ _17 = i_7 != 0;
+ _12 = (int) _17;
+ if (i_7 == _12)
+ goto <bb 9>; [50.00%]
+ else
+ goto <bb 10>; [50.00%]
+
+ <bb 9> [local count: 268435456]:
+ d = 0B;
+
+ <bb 10> [local count: 536870913]:
+ e.1_3 = e;
+ *e.1_3 = 9;
+ e = 0B;
+ d.2_4 = d;
+ if (d.2_4 == 0B)
+
+ The first if is not optimized before, until vrp2 which is
+ too late as there are no passes which will then find the
+ load of d in `d.2_4 = d;` was `0B` after vrp2.
+
+ Now in forwprop3 (after phiopt2), we optimize:
+ _17 = i_7 != 0;
+ _12 = (int) _17;
+ if (i_7 == _12)
+ into just:
+ _t = (unsigned)i_7;
+ if (_t <= 1)
+
+ And then during ccp3, that is optimized away and that is optimized
+ early enough now that the load `d.2_4 = d;` is optimizd to just
+ `d.2_4 = 0B;`
+ */
+
+/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
--
2.31.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part
2023-07-12 16:08 [PATCH] Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part Andrew Pinski
@ 2023-07-13 7:38 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2023-07-13 7:38 UTC (permalink / raw)
To: Andrew Pinski; +Cc: gcc-patches
On Wed, Jul 12, 2023 at 6:09 PM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This fixes part of PR 110293, for the outer comparison case
> being `!=` or `==`. In turn PR 110539 is able to be optimized
> again as the if statement for `(a&1) == ((a & 1) != 0)` gets optimized
> to `false` early enough to allow FRE/DOM to do a CSE for memory store/load.
>
> OK? Bootstrapped and tested on x86_64-linux with no regressions.
OK.
Thanks,
Richard.
> gcc/ChangeLog:
>
> PR tree-optimization/110293
> PR tree-optimization/110539
> * match.pd: Expand the `x != (typeof x)(x == 0)`
> pattern to handle where the inner and outer comparsions
> are either `!=` or `==` and handle other constants
> than 0.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/pr110293-1.c: New test.
> * gcc.dg/tree-ssa/pr110539-1.c: New test.
> * gcc.dg/tree-ssa/pr110539-2.c: New test.
> * gcc.dg/tree-ssa/pr110539-3.c: New test.
> * gcc.dg/tree-ssa/pr110539-4.c: New test.
> ---
> gcc/match.pd | 39 ++++++++--
> gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c | 58 +++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c | 12 ++++
> gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c | 12 ++++
> gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c | 75 ++++++++++++++++++++
> gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c | 82 ++++++++++++++++++++++
> 6 files changed, 274 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 8543f777a28..351d9285e92 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -6429,10 +6429,41 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (if (TYPE_UNSIGNED (TREE_TYPE (@0)))
> { constant_boolean_node (false, type); }))
>
> -/* x != (typeof x)(x == 0) is always true. */
> -(simplify
> - (ne:c @0 (convert (eq @0 integer_zerop)))
> - { constant_boolean_node (true, type); })
> +/* x != (typeof x)(x == CST) -> CST == 0 ? 1 : (CST == 1 ? (x!=0&&x!=1) : x != 0) */
> +/* x != (typeof x)(x != CST) -> CST == 1 ? 1 : (CST == 0 ? (x!=0&&x!=1) : x != 1) */
> +/* x == (typeof x)(x == CST) -> CST == 0 ? 0 : (CST == 1 ? (x==0||x==1) : x != 0) */
> +/* x == (typeof x)(x != CST) -> CST == 1 ? 0 : (CST == 0 ? (x==0||x==1) : x != 1) */
> +(for outer (ne eq)
> + (for inner (ne eq)
> + (simplify
> + (outer:c @0 (convert (inner @0 INTEGER_CST@1)))
> + (with {
> + bool cst1 = integer_onep (@1);
> + bool cst0 = integer_zerop (@1);
> + bool innereq = inner == EQ_EXPR;
> + bool outereq = outer == EQ_EXPR;
> + }
> + (switch
> + (if (innereq ? cst0 : cst1)
> + { constant_boolean_node (!outereq, type); })
> + (if (innereq ? cst1 : cst0)
> + (with {
> + tree utype = unsigned_type_for (TREE_TYPE (@0));
> + tree ucst1 = build_one_cst (utype);
> + }
> + (if (!outereq)
> + (gt (convert:utype @0) { ucst1; })
> + (le (convert:utype @0) { ucst1; })
> + )
> + )
> + )
> + (if (innereq)
> + (ne @0 { build_zero_cst (TREE_TYPE (@0)); }))
> + (ne @0 { build_one_cst (TREE_TYPE (@0)); }))
> + )
> + )
> + )
> +)
>
> (for cmp (unordered ordered unlt unle ungt unge uneq ltgt)
> /* If the second operand is NaN, the result is constant. */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
> new file mode 100644
> index 00000000000..24aea1a2d03
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110293-1.c
> @@ -0,0 +1,58 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized-raw" } */
> +
> +_Bool eqeq0(unsigned x)
> +{
> + return x == (x == 0);
> +}
> +_Bool eqeq1(unsigned x)
> +{
> + return x == (x == 1);
> +}
> +_Bool eqeq2(unsigned x)
> +{
> + return x == (x == 2);
> +}
> +
> +_Bool neeq0(unsigned x)
> +{
> + return x != (x == 0);
> +}
> +_Bool neeq1(unsigned x)
> +{
> + return x != (x == 1);
> +}
> +_Bool neeq2(unsigned x)
> +{
> + return x != (x == 2);
> +}
> +
> +_Bool eqne0(unsigned x)
> +{
> + return x == (x != 0);
> +}
> +_Bool eqne1(unsigned x)
> +{
> + return x == (x != 1);
> +}
> +_Bool eqne2(unsigned x)
> +{
> + return x == (x != 2);
> +}
> +
> +_Bool nene0(unsigned x)
> +{
> + return x != (x != 0);
> +}
> +_Bool nene1(unsigned x)
> +{
> + return x != (x != 1);
> +}
> +_Bool nene2(unsigned x)
> +{
> + return x != (x != 2);
> +}
> +
> +/* All of these functions should have removed the inner most comparison which
> + means all of the conversions from bool to unsigned should have been removed too. */
> +/* { dg-final { scan-tree-dump-not "nop_expr," "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
> new file mode 100644
> index 00000000000..6ba864cdd13
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-1.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +int f(int a)
> +{
> + int b = a & 1;
> + int c = b != 0;
> + return c == b;
> +}
> +
> +/* This should be optimized to just return 1; */
> +/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
> +/* { dg-final { scan-tree-dump "return 1;" "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
> new file mode 100644
> index 00000000000..17874d349ef
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-2.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-optimized" } */
> +int f(int a)
> +{
> + int b = a & 1;
> + int c = b == 0;
> + return c == b;
> +}
> +
> +/* This should be optimized to just return 0; */
> +/* { dg-final { scan-tree-dump-not " == " "optimized"} } */
> +/* { dg-final { scan-tree-dump "return 0;" "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
> new file mode 100644
> index 00000000000..e2bd4dfb45d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-3.c
> @@ -0,0 +1,75 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +void foo(void);
> +static int a, c = 1;
> +static short b;
> +static int *d = &c, *e = &a;
> +static int **f = &d;
> +void __assert_fail() __attribute__((__noreturn__));
> +static void g(short h) {
> + if (*d)
> + ;
> + else {
> + if (e) __assert_fail();
> + if (a) {
> + __builtin_unreachable();
> + } else
> + __assert_fail();
> + }
> + if ((((0, 0) || h) == h) + b) *f = 0;
> +}
> +int main() {
> + int i = 0 != 10 & a;
> + g(i);
> + *e = 9;
> + e = 0;
> + if (d == 0)
> + ;
> + else
> + foo();
> + ;
> +}
> +/* The call to foo should be optimized away. */
> +/* The missed optimization at -O2 here was:
> + int b = a & 1;
> + int c = b != 0;
> + int d = c == b;
> + not being optimized to 1 early enough, it is done in vrp2 but
> + that is too late.
> + In phiopt2 we got:
> + _17 = i_7 != 0;
> + _12 = (int) _17;
> + if (i_7 == _12)
> + goto <bb 9>; [50.00%]
> + else
> + goto <bb 10>; [50.00%]
> +
> + <bb 9> [local count: 268435456]:
> + d = 0B;
> +
> + <bb 10> [local count: 536870913]:
> + e.1_3 = e;
> + *e.1_3 = 9;
> + e = 0B;
> + d.2_4 = d;
> + if (d.2_4 == 0B)
> +
> + The first if is not optimized before, until vrp2 which is
> + too late as there are no passes which will then find the
> + load of d in `d.2_4 = d;` was `0B` after vrp2.
> +
> + Now in forwprop3 (after phiopt2), we optimize:
> + _17 = i_7 != 0;
> + _12 = (int) _17;
> + if (i_7 == _12)
> + into just:
> + _t = (unsigned)i_7;
> + if (_t <= 1)
> +
> + And then during ccp3, that is optimized away and that is optimized
> + early enough now that the load `d.2_4 = d;` is optimizd to just
> + `d.2_4 = 0B;`
> + */
> +
> +/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
> new file mode 100644
> index 00000000000..2c03dcc87fa
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr110539-4.c
> @@ -0,0 +1,82 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fstrict-aliasing -fdump-tree-optimized" } */
> +
> +/* This is a small variant of pr110539-3.c using -O1 -fstrict-aliasing
> + rather than -O2. Just to show VRP and PRE is not needed to optimize
> + the call to foo away. */
> +
> +
> +void foo(void);
> +static int a, c = 1;
> +static short b;
> +static int *d = &c, *e = &a;
> +static int **f = &d;
> +void __assert_fail() __attribute__((__noreturn__));
> +static void g(int h) {
> + if (*d)
> + ;
> + else {
> + if (e) __assert_fail();
> + if (a) {
> + __builtin_unreachable();
> + } else
> + __assert_fail();
> + }
> + if (((h!=0) == h) + b) *f = 0;
> +}
> +
> +int main() {
> + int i = 0 != 10 & a;
> + g(i);
> + *e = 9;
> + e = 0;
> + if (d == 0)
> + ;
> + else
> + foo();
> + ;
> +}
> +
> +/* The call to foo should be optimized away. */
> +/* The missed optimization at -O1 here was:
> + int b = a & 1;
> + int c = b != 0;
> + int d = c == b;
> + not being optimized to 1 early enough, it is done in vrp2 but
> + that is too late.
> + In phiopt2 we got:
> + _17 = i_7 != 0;
> + _12 = (int) _17;
> + if (i_7 == _12)
> + goto <bb 9>; [50.00%]
> + else
> + goto <bb 10>; [50.00%]
> +
> + <bb 9> [local count: 268435456]:
> + d = 0B;
> +
> + <bb 10> [local count: 536870913]:
> + e.1_3 = e;
> + *e.1_3 = 9;
> + e = 0B;
> + d.2_4 = d;
> + if (d.2_4 == 0B)
> +
> + The first if is not optimized before, until vrp2 which is
> + too late as there are no passes which will then find the
> + load of d in `d.2_4 = d;` was `0B` after vrp2.
> +
> + Now in forwprop3 (after phiopt2), we optimize:
> + _17 = i_7 != 0;
> + _12 = (int) _17;
> + if (i_7 == _12)
> + into just:
> + _t = (unsigned)i_7;
> + if (_t <= 1)
> +
> + And then during ccp3, that is optimized away and that is optimized
> + early enough now that the load `d.2_4 = d;` is optimizd to just
> + `d.2_4 = 0B;`
> + */
> +
> +/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
> --
> 2.31.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-07-12 16:08 [PATCH] Fix part of PR 110293: `A NEEQ (A NEEQ CST)` part Andrew Pinski
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