* [PATCH] tree-optimization/105971 - less surprising refs_may_alias_p_2
@ 2022-06-15 11:13 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-06-15 11:13 UTC (permalink / raw)
To: gcc-patches
When DSE asks whether __real a is using __imag a it gets a surprising
result when a is a FUNCTION_DECL. The following makes sure this case
is less surprising to callers but keeping the bail-out for the
non-decl case where it is true that PTA doesn't track aliases to code
correctly.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2022-06-15 Richard Biener <rguenther@suse.de>
PR tree-optimization/105971
* tree-ssa-alias.cc (refs_may_alias_p_2): Put bail-out for
FUNCTION_DECL and LABEL_DECL refs after decl-decl disambiguation
to leak less surprising alias results.
* gcc.dg/torture/pr106971.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr106971.c | 12 ++++++++++++
gcc/tree-ssa-alias.cc | 18 +++++++++---------
2 files changed, 21 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr106971.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr106971.c b/gcc/testsuite/gcc.dg/torture/pr106971.c
new file mode 100644
index 00000000000..33f21056e62
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr106971.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+void a()
+{
+ int b;
+ int c;
+ int d = (__INTPTR_TYPE__)a;
+ _Complex float *e = (_Complex float *)a;
+ for (;;) {
+ (*e += d) / b ?: 0;
+ }
+}
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 063f1893851..b1e7a2d5afc 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -2397,15 +2397,6 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
|| CONSTANT_CLASS_P (base2))
return false;
- /* We can end up referring to code via function and label decls.
- As we likely do not properly track code aliases conservatively
- bail out. */
- if (TREE_CODE (base1) == FUNCTION_DECL
- || TREE_CODE (base1) == LABEL_DECL
- || TREE_CODE (base2) == FUNCTION_DECL
- || TREE_CODE (base2) == LABEL_DECL)
- return true;
-
/* Two volatile accesses always conflict. */
if (ref1->volatile_p
&& ref2->volatile_p)
@@ -2432,6 +2423,15 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
ref2ref, base2, offset2, max_size2,
ref2->size);
+ /* We can end up referring to code via function and label decls.
+ As we likely do not properly track code aliases conservatively
+ bail out. */
+ if (TREE_CODE (base1) == FUNCTION_DECL
+ || TREE_CODE (base1) == LABEL_DECL
+ || TREE_CODE (base2) == FUNCTION_DECL
+ || TREE_CODE (base2) == LABEL_DECL)
+ return true;
+
/* Handle restrict based accesses.
??? ao_ref_base strips inner MEM_REF [&decl], recover from that
here. */
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] tree-optimization/105971 - less surprising refs_may_alias_p_2
@ 2022-06-15 11:13 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-06-15 11:13 UTC (permalink / raw)
To: gcc-patches
When DSE asks whether __real a is using __imag a it gets a surprising
result when a is a FUNCTION_DECL. The following makes sure this case
is less surprising to callers but keeping the bail-out for the
non-decl case where it is true that PTA doesn't track aliases to code
correctly.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2022-06-15 Richard Biener <rguenther@suse.de>
PR tree-optimization/105971
* tree-ssa-alias.cc (refs_may_alias_p_2): Put bail-out for
FUNCTION_DECL and LABEL_DECL refs after decl-decl disambiguation
to leak less surprising alias results.
* gcc.dg/torture/pr106971.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr106971.c | 12 ++++++++++++
gcc/tree-ssa-alias.cc | 18 +++++++++---------
2 files changed, 21 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr106971.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr106971.c b/gcc/testsuite/gcc.dg/torture/pr106971.c
new file mode 100644
index 00000000000..33f21056e62
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr106971.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+void a()
+{
+ int b;
+ int c;
+ int d = (__INTPTR_TYPE__)a;
+ _Complex float *e = (_Complex float *)a;
+ for (;;) {
+ (*e += d) / b ?: 0;
+ }
+}
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 063f1893851..b1e7a2d5afc 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -2397,15 +2397,6 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
|| CONSTANT_CLASS_P (base2))
return false;
- /* We can end up referring to code via function and label decls.
- As we likely do not properly track code aliases conservatively
- bail out. */
- if (TREE_CODE (base1) == FUNCTION_DECL
- || TREE_CODE (base1) == LABEL_DECL
- || TREE_CODE (base2) == FUNCTION_DECL
- || TREE_CODE (base2) == LABEL_DECL)
- return true;
-
/* Two volatile accesses always conflict. */
if (ref1->volatile_p
&& ref2->volatile_p)
@@ -2432,6 +2423,15 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
ref2ref, base2, offset2, max_size2,
ref2->size);
+ /* We can end up referring to code via function and label decls.
+ As we likely do not properly track code aliases conservatively
+ bail out. */
+ if (TREE_CODE (base1) == FUNCTION_DECL
+ || TREE_CODE (base1) == LABEL_DECL
+ || TREE_CODE (base2) == FUNCTION_DECL
+ || TREE_CODE (base2) == LABEL_DECL)
+ return true;
+
/* Handle restrict based accesses.
??? ao_ref_base strips inner MEM_REF [&decl], recover from that
here. */
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] tree-optimization/105971 - less surprising refs_may_alias_p_2
@ 2022-06-15 11:13 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-06-15 11:13 UTC (permalink / raw)
To: gcc-patches
When DSE asks whether __real a is using __imag a it gets a surprising
result when a is a FUNCTION_DECL. The following makes sure this case
is less surprising to callers but keeping the bail-out for the
non-decl case where it is true that PTA doesn't track aliases to code
correctly.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2022-06-15 Richard Biener <rguenther@suse.de>
PR tree-optimization/105971
* tree-ssa-alias.cc (refs_may_alias_p_2): Put bail-out for
FUNCTION_DECL and LABEL_DECL refs after decl-decl disambiguation
to leak less surprising alias results.
* gcc.dg/torture/pr106971.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr106971.c | 12 ++++++++++++
gcc/tree-ssa-alias.cc | 18 +++++++++---------
2 files changed, 21 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr106971.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr106971.c b/gcc/testsuite/gcc.dg/torture/pr106971.c
new file mode 100644
index 00000000000..33f21056e62
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr106971.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+
+void a()
+{
+ int b;
+ int c;
+ int d = (__INTPTR_TYPE__)a;
+ _Complex float *e = (_Complex float *)a;
+ for (;;) {
+ (*e += d) / b ?: 0;
+ }
+}
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 063f1893851..b1e7a2d5afc 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -2397,15 +2397,6 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
|| CONSTANT_CLASS_P (base2))
return false;
- /* We can end up referring to code via function and label decls.
- As we likely do not properly track code aliases conservatively
- bail out. */
- if (TREE_CODE (base1) == FUNCTION_DECL
- || TREE_CODE (base1) == LABEL_DECL
- || TREE_CODE (base2) == FUNCTION_DECL
- || TREE_CODE (base2) == LABEL_DECL)
- return true;
-
/* Two volatile accesses always conflict. */
if (ref1->volatile_p
&& ref2->volatile_p)
@@ -2432,6 +2423,15 @@ refs_may_alias_p_2 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p)
ref2ref, base2, offset2, max_size2,
ref2->size);
+ /* We can end up referring to code via function and label decls.
+ As we likely do not properly track code aliases conservatively
+ bail out. */
+ if (TREE_CODE (base1) == FUNCTION_DECL
+ || TREE_CODE (base1) == LABEL_DECL
+ || TREE_CODE (base2) == FUNCTION_DECL
+ || TREE_CODE (base2) == LABEL_DECL)
+ return true;
+
/* Handle restrict based accesses.
??? ao_ref_base strips inner MEM_REF [&decl], recover from that
here. */
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
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