* [PATCH] Improve ptr_derefs_may_alias_p for the case of &STRING_CST
@ 2022-07-26 10:08 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-07-26 10:08 UTC (permalink / raw)
To: gcc-patches
When the first pointer happens to be a pointer to a STRING_CST we
give up too early since the 2nd pointer handling could still end
up with a DECL for example which can disambiguate against a STRING_CST
just fine.
Boostrapped and tested on x86_64-unknown-linux-gnu, pushed.
* tree-ssa-alias.cc (ptr_derefs_may_alias_p): If ptr1
points to a constant continue checking ptr2.
---
gcc/tree-ssa-alias.cc | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 390cd875074..b4c65da5718 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -349,7 +349,9 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
else if (base
&& DECL_P (base))
return ptr_deref_may_alias_decl_p (ptr2, base);
- else
+ /* Try ptr2 when ptr1 points to a constant. */
+ else if (base
+ && !CONSTANT_CLASS_P (base))
return true;
}
if (TREE_CODE (ptr2) == ADDR_EXPR)
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] Improve ptr_derefs_may_alias_p for the case of &STRING_CST
@ 2022-07-26 10:08 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-07-26 10:08 UTC (permalink / raw)
To: gcc-patches
When the first pointer happens to be a pointer to a STRING_CST we
give up too early since the 2nd pointer handling could still end
up with a DECL for example which can disambiguate against a STRING_CST
just fine.
Boostrapped and tested on x86_64-unknown-linux-gnu, pushed.
* tree-ssa-alias.cc (ptr_derefs_may_alias_p): If ptr1
points to a constant continue checking ptr2.
---
gcc/tree-ssa-alias.cc | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 390cd875074..b4c65da5718 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -349,7 +349,9 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
else if (base
&& DECL_P (base))
return ptr_deref_may_alias_decl_p (ptr2, base);
- else
+ /* Try ptr2 when ptr1 points to a constant. */
+ else if (base
+ && !CONSTANT_CLASS_P (base))
return true;
}
if (TREE_CODE (ptr2) == ADDR_EXPR)
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] Improve ptr_derefs_may_alias_p for the case of &STRING_CST
@ 2022-07-26 10:08 Richard Biener
0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2022-07-26 10:08 UTC (permalink / raw)
To: gcc-patches
When the first pointer happens to be a pointer to a STRING_CST we
give up too early since the 2nd pointer handling could still end
up with a DECL for example which can disambiguate against a STRING_CST
just fine.
Boostrapped and tested on x86_64-unknown-linux-gnu, pushed.
* tree-ssa-alias.cc (ptr_derefs_may_alias_p): If ptr1
points to a constant continue checking ptr2.
---
gcc/tree-ssa-alias.cc | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-ssa-alias.cc b/gcc/tree-ssa-alias.cc
index 390cd875074..b4c65da5718 100644
--- a/gcc/tree-ssa-alias.cc
+++ b/gcc/tree-ssa-alias.cc
@@ -349,7 +349,9 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
else if (base
&& DECL_P (base))
return ptr_deref_may_alias_decl_p (ptr2, base);
- else
+ /* Try ptr2 when ptr1 points to a constant. */
+ else if (base
+ && !CONSTANT_CLASS_P (base))
return true;
}
if (TREE_CODE (ptr2) == ADDR_EXPR)
--
2.35.3
^ permalink raw reply [flat|nested] 3+ messages in thread
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