https://gcc.gnu.org/g:d882e48d48bf300941c3610c5af157c64ccf0a84
commit r15-7056-gd882e48d48bf300941c3610c5af157c64ccf0a84
Author: Jakub Jelinek <ja...@redhat.com>
Date: Mon Jan 20 10:24:18 2025 +0100
tree-ssa-dce: Fix calloc handling [PR118224]
As reported by Dimitar, this should have been a multiplication, but wasn't
caught because in the test (~(__SIZE_TYPE__) 0) / 2 is the largest accepted
size and so adding 3 to it also resulted in "overflow".
The following patch adds one subtest to really verify it is a multiplication
and fixes the operation.
2025-01-20 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/118224
* tree-ssa-dce.cc (is_removable_allocation_p): Multiply a1 by a2
instead of adding it.
* gcc.dg/pr118224.c: New test.
Diff:
---
gcc/testsuite/gcc.dg/pr118224.c | 2 ++
gcc/tree-ssa-dce.cc | 2 +-
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/gcc/testsuite/gcc.dg/pr118224.c b/gcc/testsuite/gcc.dg/pr118224.c
index 683f4dc8f631..a254e2c2d31e 100644
--- a/gcc/testsuite/gcc.dg/pr118224.c
+++ b/gcc/testsuite/gcc.dg/pr118224.c
@@ -27,5 +27,7 @@ main ()
#endif
if (__builtin_calloc ((~(__SIZE_TYPE__) 0) / 2, 3))
__builtin_abort ();
+ if (__builtin_calloc ((~(__SIZE_TYPE__) 0) / 16, 64))
+ __builtin_abort ();
foo (1);
}
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index 5b3037ac625c..be21a2d0b507 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -331,7 +331,7 @@ is_removable_allocation_p (gcall *stmt, bool non_null_check)
return false;
if (TREE_CODE (a1) == INTEGER_CST
&& TREE_CODE (a2) == INTEGER_CST
- && (wi::to_widest (a1) + wi::to_widest (a2)
+ && (wi::to_widest (a1) * wi::to_widest (a2)
> tree_to_uhwi (TYPE_MAX_VALUE (ptrdiff_type_node))))
return false;
return true;
