On Fri, 24 Mar 2023, Jan Hubicka wrote:
> > From d438a0d84cafced85c90204cba81de0f60ad0073 Mon Sep 17 00:00:00 2001
> > From: Richard Biener <rguent...@suse.de>
> > Date: Thu, 16 Mar 2023 13:51:19 +0100
> > Subject: [PATCH] tree-optimization/106912 - clear const attribute from
> > fntype
> > To: gcc-patches@gcc.gnu.org
> >
> > The following makes sure that after clearing pure/const from
> > instrumented function declarations we are adjusting call statements
> > fntype as well to handle indirect calls and because gimple_call_flags
> > looks at both decl and fntype.
> >
> > Like the pure/const flag clearing on decls we refrain from touching
> > calls to known functions that do not have a body in the current TU.
> >
> > PR tree-optimization/106912
> > * tree-profile.cc (tree_profiling): Update stmts only when
> > profiling or testing coverage. Make sure to update calls
> > fntype, stripping 'const' there.
> >
> > * gcc.dg/profile-generate-4.c: New testcase.
> > ---
> > gcc/testsuite/gcc.dg/profile-generate-4.c | 19 ++++++++++++
> > gcc/tree-profile.cc | 38 +++++++++++++++++------
> > 2 files changed, 47 insertions(+), 10 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.dg/profile-generate-4.c
> >
> > diff --git a/gcc/testsuite/gcc.dg/profile-generate-4.c
> > b/gcc/testsuite/gcc.dg/profile-generate-4.c
> > new file mode 100644
> > index 00000000000..c2b999fe4cb
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/profile-generate-4.c
> > @@ -0,0 +1,19 @@
> > +/* PR106912 */
> > +/* { dg-require-profiling "-fprofile-generate" } */
> > +/* { dg-options "-O2 -fprofile-generate -ftree-vectorize" } */
> > +
> > +__attribute__ ((__simd__))
> > +__attribute__ ((__nothrow__ , __leaf__ , __const__, __noinline__))
> > +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 ea9d7a23443..7854cd4bc31 100644
> > --- a/gcc/tree-profile.cc
> > +++ b/gcc/tree-profile.cc
> > @@ -835,16 +835,34 @@ tree_profiling (void)
> >
> > push_cfun (DECL_STRUCT_FUNCTION (node->decl));
> >
> > - FOR_EACH_BB_FN (bb, cfun)
> > - {
> > - gimple_stmt_iterator gsi;
> > - for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> > - {
> > - gimple *stmt = gsi_stmt (gsi);
> > - if (is_gimple_call (stmt))
> > - update_stmt (stmt);
> > - }
> > - }
> > + if (profile_arc_flag || flag_test_coverage)
> > + FOR_EACH_BB_FN (bb, cfun)
> > + {
> > + gimple_stmt_iterator gsi;
> > + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> > + {
> > + gcall *call = dyn_cast <gcall *> (gsi_stmt (gsi));
> > + if (!call)
> > + continue;
> > +
> > + /* We do not clear pure/const on decls without body. */
> > + tree fndecl = gimple_call_fndecl (call);
> > + if (fndecl && !gimple_has_body_p (fndecl))
> > + continue;
>
> Actually on second thought, I think I can break this either by making
> the wraping function to be thunk or alias or by moving it to different
> compilation unit.
> Also with LTO we will get body later.
>
> So I think we need to drop this optimization.
It's the same condition guarding the set_{const,pure}_flag call earlier
(but yes, I agree). So it isn't covered by the regression so we
should address this for next stage1.
Richard.
