> IPA profile instrumentation tries to clear the pure and const > flags of functions but that's quite hopeless in particular for > const since that attribute prevails on the type and thus on each > call to the function leading to inconsistencies in the IL and > eventual checking ICEs. There's no good reason to do this and > it wouldn't fixup any indirect calls so just don't. No other > instrumentation GCC does bothers about this.
This was mostly meant to deadl with situation where we auto-detect function to be const and then partially inline it to a loop. Then both caller and callee accesses same counters in the memory and if you move load/stores out of the loop in caller you lose counters and get inconsistencies at profile read-in time. Honza > > Bootstrap and regtest pending on x86_64-unknown-linux-gnu, OK? > > Thanks, > Richard. > > PR tree-optimization/106912 > * tree-profile.cc (tree_profiling): Do not clear pure/const > flags. > > * gcc.dg/pr106912.c: New testcase. > --- > gcc/testsuite/gcc.dg/pr106912.c | 16 ++++++++++++++++ > gcc/tree-profile.cc | 3 --- > 2 files changed, 16 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/pr106912.c > > diff --git a/gcc/testsuite/gcc.dg/pr106912.c b/gcc/testsuite/gcc.dg/pr106912.c > new file mode 100644 > index 00000000000..8faa877d8b3 > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/pr106912.c > @@ -0,0 +1,16 @@ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -fPIC -ftree-vectorize -fprofile-generate" } */ > + > +__attribute__ ((__simd__)) > +__attribute__ ((__nothrow__ , __leaf__ , __const__)) > +double foo (double x); > +void bar(double *f, int n) > +{ > + int i; > + for (i = 0; i < n; i++) > + f[i] = foo(f[i]); > +} > +double foo(double x) > +{ > + return x * x / 3.0; > +} > diff --git a/gcc/tree-profile.cc b/gcc/tree-profile.cc > index 2beb49241f2..5491b398870 100644 > --- a/gcc/tree-profile.cc > +++ b/gcc/tree-profile.cc > @@ -814,9 +814,6 @@ tree_profiling (void) > /* Don't profile functions produced for builtin stuff. */ > if (DECL_SOURCE_LOCATION (node->decl) == BUILTINS_LOCATION) > continue; > - > - node->set_const_flag (false, false); > - node->set_pure_flag (false, false); > } > > /* Update call statements and rebuild the cgraph. */ > -- > 2.35.3