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 &lattice, int depth, else if (gcall *call = dyn_cast (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); +}