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* [gcc r12-3059] Clear EAF_NOCLOBBER for indirect calls
@ 2021-08-22 18:58 Jan Hubicka
0 siblings, 0 replies; only message in thread
From: Jan Hubicka @ 2021-08-22 18:58 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:9b08f7764cecd16cba84944f2a8b67a7f73a7ce7
commit r12-3059-g9b08f7764cecd16cba84944f2a8b67a7f73a7ce7
Author: Jan Hubicka <jh@suse.cz>
Date: Sun Aug 22 20:57:19 2021 +0200
Clear EAF_NOCLOBBER for indirect calls
gcc/ChangeLog:
2021-08-22 Jan Hubicka <hubicka@ucw.cz>
Martin Liska <mliska@suse.cz>
PR middle-end/101949
* ipa-modref.c (analyze_ssa_name_flags): Indirect call implies
~EAF_NOCLOBBER.
gcc/testsuite/ChangeLog:
2021-08-22 Jan Hubicka <hubicka@ucw.cz>
Martin Liska <mliska@suse.cz>
* gcc.dg/lto/pr101949_0.c: New test.
* gcc.dg/lto/pr101949_1.c: New test.
Diff:
---
gcc/ipa-modref.c | 9 +++++++++
gcc/testsuite/gcc.dg/lto/pr101949_0.c | 20 ++++++++++++++++++++
gcc/testsuite/gcc.dg/lto/pr101949_1.c | 4 ++++
3 files changed, 33 insertions(+)
diff --git a/gcc/ipa-modref.c b/gcc/ipa-modref.c
index fafd804d4ba..549153865b8 100644
--- a/gcc/ipa-modref.c
+++ b/gcc/ipa-modref.c
@@ -1700,6 +1700,15 @@ analyze_ssa_name_flags (tree name, vec<modref_lattice> &lattice, int depth,
else if (gcall *call = dyn_cast <gcall *> (use_stmt))
{
tree callee = gimple_call_fndecl (call);
+
+ /* IPA PTA internally it treats calling a function as "writing" to
+ the argument space of all functions the function pointer points to
+ (PR101949). We can not drop EAF_NOCLOBBER only when ipa-pta
+ is on since that would allow propagation of this from -fno-ipa-pta
+ to -fipa-pta functions. */
+ if (gimple_call_fn (use_stmt) == name)
+ lattice[index].merge (~EAF_NOCLOBBER);
+
/* Return slot optimization would require bit of propagation;
give up for now. */
if (gimple_call_return_slot_opt_p (call)
diff --git a/gcc/testsuite/gcc.dg/lto/pr101949_0.c b/gcc/testsuite/gcc.dg/lto/pr101949_0.c
new file mode 100644
index 00000000000..142dffe8780
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101949_0.c
@@ -0,0 +1,20 @@
+/* { dg-lto-do run } */
+/* { dg-lto-options { "-O2 -fipa-pta -flto -flto-partition=1to1" } } */
+
+extern int bar (int (*)(int *), int *);
+
+static int x;
+
+static int __attribute__ ((noinline)) foo (int *p)
+{
+ *p = 1;
+ x = 0;
+ return *p;
+}
+
+int main ()
+{
+ if (bar (foo, &x) != 0)
+ __builtin_abort ();
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/lto/pr101949_1.c b/gcc/testsuite/gcc.dg/lto/pr101949_1.c
new file mode 100644
index 00000000000..871d15c9bfb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lto/pr101949_1.c
@@ -0,0 +1,4 @@
+int __attribute__((noinline,noclone)) bar (int (*fn)(int *), int *p)
+{
+ return fn (p);
+}
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