> 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.
Honza
> +
> + /* Drop the const attribute from the call type (the pure
> + attribute is not available on types). */
> + tree fntype = gimple_call_fntype (call);
> + if (fntype && TYPE_READONLY (fntype))
> + gimple_call_set_fntype
> + (call, build_qualified_type (fntype, (TYPE_QUALS (fntype)
> + & ~TYPE_QUAL_CONST)));
> +
> + /* Update virtual operands of calls to no longer const/pure
> + functions. */
> + update_stmt (call);
> + }
> + }
>
> /* re-merge split blocks. */
> cleanup_tree_cfg ();
> --
> 2.35.3
>
