* [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253]
@ 2023-01-04 9:13 Jakub Jelinek
2023-01-04 11:12 ` Aldy Hernandez
2023-01-04 18:45 ` Aldy Hernandez
0 siblings, 2 replies; 3+ messages in thread
From: Jakub Jelinek @ 2023-01-04 9:13 UTC (permalink / raw)
To: Aldy Hernandez, Andrew MacLeod; +Cc: gcc-patches
Hi!
maybe_set_nonzero_bits calls set_nonzero_bits which asserts that
var doesn't have pointer type. While we could punt for those
cases, I think we can handle at least some easy cases.
Earlier in maybe_set_nonzero_bits we've checked this is on
(var & cst) == 0
edge and the other edge is __builtin_unreachable, so if cst
is say 3 as in the testcase, we want to turn it into 4 byte alignment
of the pointer.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-01-04 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/108253
* tree-vrp.cc (maybe_set_nonzero_bits): Handle var with pointer
types.
* g++.dg/opt/pr108253.C: New test.
--- gcc/tree-vrp.cc.jj 2023-01-02 09:32:53.634833769 +0100
+++ gcc/tree-vrp.cc 2023-01-03 15:57:51.613239761 +0100
@@ -789,8 +789,22 @@ maybe_set_nonzero_bits (edge e, tree var
return;
}
cst = gimple_assign_rhs2 (stmt);
- set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
- wi::to_wide (cst)));
+ if (POINTER_TYPE_P (TREE_TYPE (var)))
+ {
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (var);
+ if (pi && pi->misalign)
+ return;
+ wide_int w = wi::bit_not (wi::to_wide (cst));
+ unsigned int bits = wi::ctz (w);
+ if (bits == 0 || bits >= HOST_BITS_PER_INT)
+ return;
+ unsigned int align = 1U << bits;
+ if (pi == NULL || pi->align < align)
+ set_ptr_info_alignment (get_ptr_info (var), align, 0);
+ }
+ else
+ set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
+ wi::to_wide (cst)));
}
/* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
--- gcc/testsuite/g++.dg/opt/pr108253.C.jj 2023-01-03 16:02:16.366438488 +0100
+++ gcc/testsuite/g++.dg/opt/pr108253.C 2023-01-03 16:02:33.549191780 +0100
@@ -0,0 +1,48 @@
+// PR tree-optimization/108253
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2" }
+
+struct S
+{
+ int *s;
+ S () : s (new int) {}
+ S (const S &r) noexcept : s (r.s) { __atomic_fetch_add (r.s, 1, 4); }
+};
+struct T
+{
+ explicit T (const S &x) : t (x) {}
+ const S t;
+};
+struct U
+{
+ operator int () const { new T (u); return 0; }
+ S u;
+};
+bool foo (int matcher);
+unsigned long bar (unsigned long pos, unsigned long end_pos);
+struct V
+{
+ alignas (4) char v[4];
+};
+struct W
+{
+ void baz ()
+ {
+ if (!w) __builtin_abort ();
+ if (reinterpret_cast <__UINTPTR_TYPE__> (w->v) % 4 != 0) __builtin_abort ();
+ __builtin_unreachable ();
+ }
+ [[gnu::noinline]] void qux (unsigned long) { if (!w) bar (0, x); }
+ V *w = nullptr;
+ unsigned x = 0;
+};
+
+void
+test ()
+{
+ W w;
+ U t;
+ if (!foo (t))
+ w.baz ();
+ w.qux (0);
+}
Jakub
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253]
2023-01-04 9:13 [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253] Jakub Jelinek
@ 2023-01-04 11:12 ` Aldy Hernandez
2023-01-04 18:45 ` Aldy Hernandez
1 sibling, 0 replies; 3+ messages in thread
From: Aldy Hernandez @ 2023-01-04 11:12 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Andrew MacLeod, gcc-patches
[-- Attachment #1: Type: text/plain, Size: 3102 bytes --]
OK.
On Wed, Jan 4, 2023, 10:13 Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> maybe_set_nonzero_bits calls set_nonzero_bits which asserts that
> var doesn't have pointer type. While we could punt for those
> cases, I think we can handle at least some easy cases.
> Earlier in maybe_set_nonzero_bits we've checked this is on
> (var & cst) == 0
> edge and the other edge is __builtin_unreachable, so if cst
> is say 3 as in the testcase, we want to turn it into 4 byte alignment
> of the pointer.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-01-04 Jakub Jelinek <jakub@redhat.com>
>
> PR tree-optimization/108253
> * tree-vrp.cc (maybe_set_nonzero_bits): Handle var with pointer
> types.
>
> * g++.dg/opt/pr108253.C: New test.
>
> --- gcc/tree-vrp.cc.jj 2023-01-02 09:32:53.634833769 +0100
> +++ gcc/tree-vrp.cc 2023-01-03 15:57:51.613239761 +0100
> @@ -789,8 +789,22 @@ maybe_set_nonzero_bits (edge e, tree var
> return;
> }
> cst = gimple_assign_rhs2 (stmt);
> - set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
> - wi::to_wide (cst)));
> + if (POINTER_TYPE_P (TREE_TYPE (var)))
> + {
> + struct ptr_info_def *pi = SSA_NAME_PTR_INFO (var);
> + if (pi && pi->misalign)
> + return;
> + wide_int w = wi::bit_not (wi::to_wide (cst));
> + unsigned int bits = wi::ctz (w);
> + if (bits == 0 || bits >= HOST_BITS_PER_INT)
> + return;
> + unsigned int align = 1U << bits;
> + if (pi == NULL || pi->align < align)
> + set_ptr_info_alignment (get_ptr_info (var), align, 0);
> + }
> + else
> + set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
> + wi::to_wide (cst)));
> }
>
> /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
> --- gcc/testsuite/g++.dg/opt/pr108253.C.jj 2023-01-03
> 16:02:16.366438488 +0100
> +++ gcc/testsuite/g++.dg/opt/pr108253.C 2023-01-03 16:02:33.549191780 +0100
> @@ -0,0 +1,48 @@
> +// PR tree-optimization/108253
> +// { dg-do compile { target c++11 } }
> +// { dg-options "-O2" }
> +
> +struct S
> +{
> + int *s;
> + S () : s (new int) {}
> + S (const S &r) noexcept : s (r.s) { __atomic_fetch_add (r.s, 1, 4); }
> +};
> +struct T
> +{
> + explicit T (const S &x) : t (x) {}
> + const S t;
> +};
> +struct U
> +{
> + operator int () const { new T (u); return 0; }
> + S u;
> +};
> +bool foo (int matcher);
> +unsigned long bar (unsigned long pos, unsigned long end_pos);
> +struct V
> +{
> + alignas (4) char v[4];
> +};
> +struct W
> +{
> + void baz ()
> + {
> + if (!w) __builtin_abort ();
> + if (reinterpret_cast <__UINTPTR_TYPE__> (w->v) % 4 != 0)
> __builtin_abort ();
> + __builtin_unreachable ();
> + }
> + [[gnu::noinline]] void qux (unsigned long) { if (!w) bar (0, x); }
> + V *w = nullptr;
> + unsigned x = 0;
> +};
> +
> +void
> +test ()
> +{
> + W w;
> + U t;
> + if (!foo (t))
> + w.baz ();
> + w.qux (0);
> +}
>
> Jakub
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253]
2023-01-04 9:13 [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253] Jakub Jelinek
2023-01-04 11:12 ` Aldy Hernandez
@ 2023-01-04 18:45 ` Aldy Hernandez
1 sibling, 0 replies; 3+ messages in thread
From: Aldy Hernandez @ 2023-01-04 18:45 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Andrew MacLeod, gcc-patches
[-- Attachment #1: Type: text/plain, Size: 3419 bytes --]
On PTO until Monday but thinking out loud here....
Shouldn't we put this code in set_nonzero_bits instead, and leave maybe*
alone? That way any possible setters may benefit from your change?
Also, havent looked (AFK) but does this change work with the global range
getter (get_global_range_query...)?
Thoughts?
Aldy
On Wed, Jan 4, 2023, 10:13 Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> maybe_set_nonzero_bits calls set_nonzero_bits which asserts that
> var doesn't have pointer type. While we could punt for those
> cases, I think we can handle at least some easy cases.
> Earlier in maybe_set_nonzero_bits we've checked this is on
> (var & cst) == 0
> edge and the other edge is __builtin_unreachable, so if cst
> is say 3 as in the testcase, we want to turn it into 4 byte alignment
> of the pointer.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2023-01-04 Jakub Jelinek <jakub@redhat.com>
>
> PR tree-optimization/108253
> * tree-vrp.cc (maybe_set_nonzero_bits): Handle var with pointer
> types.
>
> * g++.dg/opt/pr108253.C: New test.
>
> --- gcc/tree-vrp.cc.jj 2023-01-02 09:32:53.634833769 +0100
> +++ gcc/tree-vrp.cc 2023-01-03 15:57:51.613239761 +0100
> @@ -789,8 +789,22 @@ maybe_set_nonzero_bits (edge e, tree var
> return;
> }
> cst = gimple_assign_rhs2 (stmt);
> - set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
> - wi::to_wide (cst)));
> + if (POINTER_TYPE_P (TREE_TYPE (var)))
> + {
> + struct ptr_info_def *pi = SSA_NAME_PTR_INFO (var);
> + if (pi && pi->misalign)
> + return;
> + wide_int w = wi::bit_not (wi::to_wide (cst));
> + unsigned int bits = wi::ctz (w);
> + if (bits == 0 || bits >= HOST_BITS_PER_INT)
> + return;
> + unsigned int align = 1U << bits;
> + if (pi == NULL || pi->align < align)
> + set_ptr_info_alignment (get_ptr_info (var), align, 0);
> + }
> + else
> + set_nonzero_bits (var, wi::bit_and_not (get_nonzero_bits (var),
> + wi::to_wide (cst)));
> }
>
> /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
> --- gcc/testsuite/g++.dg/opt/pr108253.C.jj 2023-01-03
> 16:02:16.366438488 +0100
> +++ gcc/testsuite/g++.dg/opt/pr108253.C 2023-01-03 16:02:33.549191780 +0100
> @@ -0,0 +1,48 @@
> +// PR tree-optimization/108253
> +// { dg-do compile { target c++11 } }
> +// { dg-options "-O2" }
> +
> +struct S
> +{
> + int *s;
> + S () : s (new int) {}
> + S (const S &r) noexcept : s (r.s) { __atomic_fetch_add (r.s, 1, 4); }
> +};
> +struct T
> +{
> + explicit T (const S &x) : t (x) {}
> + const S t;
> +};
> +struct U
> +{
> + operator int () const { new T (u); return 0; }
> + S u;
> +};
> +bool foo (int matcher);
> +unsigned long bar (unsigned long pos, unsigned long end_pos);
> +struct V
> +{
> + alignas (4) char v[4];
> +};
> +struct W
> +{
> + void baz ()
> + {
> + if (!w) __builtin_abort ();
> + if (reinterpret_cast <__UINTPTR_TYPE__> (w->v) % 4 != 0)
> __builtin_abort ();
> + __builtin_unreachable ();
> + }
> + [[gnu::noinline]] void qux (unsigned long) { if (!w) bar (0, x); }
> + V *w = nullptr;
> + unsigned x = 0;
> +};
> +
> +void
> +test ()
> +{
> + W w;
> + U t;
> + if (!foo (t))
> + w.baz ();
> + w.qux (0);
> +}
>
> Jakub
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-01-04 9:13 [PATCH] vrp: Handle pointers in maybe_set_nonzero_bits [PR108253] Jakub Jelinek
2023-01-04 11:12 ` Aldy Hernandez
2023-01-04 18:45 ` Aldy Hernandez
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