https://gcc.gnu.org/g:adab597af288d6e1e0b7c3414517147995b03cc9
commit r14-10693-gadab597af288d6e1e0b7c3414517147995b03cc9
Author: Eric Botcazou <ebotca...@adacore.com>
Date: Fri Sep 20 12:32:13 2024 +0200
Fix small thinko in IPA mod/ref pass
When a memory copy operation is analyzed by analyze_ssa_name, if both the
load and store are made through the same SSA name, the store is overlooked.
gcc/
* ipa-modref.cc (modref_eaf_analysis::analyze_ssa_name): Always
process both the load and the store of a memory copy operation.
gcc/testsuite/
* gcc.dg/ipa/modref-4.c: New test.
Diff:
---
gcc/ipa-modref.cc | 3 ++-
gcc/testsuite/gcc.dg/ipa/modref-4.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/gcc/ipa-modref.cc b/gcc/ipa-modref.cc
index 10344fbb4b58..ccf788e6398c 100644
--- a/gcc/ipa-modref.cc
+++ b/gcc/ipa-modref.cc
@@ -2604,8 +2604,9 @@ modref_eaf_analysis::analyze_ssa_name (tree name, bool
deferred)
is used arbitrarily. */
if (memory_access_to (gimple_assign_rhs1 (assign), name))
m_lattice[index].merge (deref_flags (0, false));
+
/* Handle *name = *exp. */
- else if (memory_access_to (gimple_assign_lhs (assign), name))
+ if (memory_access_to (gimple_assign_lhs (assign), name))
m_lattice[index].merge_direct_store ();
}
/* Handle lhs = *name. */
diff --git a/gcc/testsuite/gcc.dg/ipa/modref-4.c
b/gcc/testsuite/gcc.dg/ipa/modref-4.c
new file mode 100644
index 000000000000..71ed1ca5f5b6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/modref-4.c
@@ -0,0 +1,34 @@
+/* { dg-options "-O" } */
+/* { dg-do run } */
+
+static __attribute__((noipa)) int foo (void)
+{
+ return 1;
+}
+
+int main (void)
+{
+ struct S { int a; int b; };
+ struct T { struct S s; };
+
+ struct T t = { { 0, 0 } };
+ struct T u;
+
+ __attribute__((noinline)) void bar (void)
+ {
+ if (foo ())
+ {
+ u = t;
+ /* OK with u.s.a = 0; */
+ }
+ }
+
+ u.s.a = 1;
+
+ bar ();
+
+ if (u.s.a != 0)
+ __builtin_abort ();
+
+ return 0;
+}
