[Bug tree-optimization/102178] [12 Regression] SPECFP 2006 470.lbm regressions on AMD Zen CPUs after r12-897-gde56f95afaaa22

jamborm at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Wed Sep 8 14:06:28 GMT 2021


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102178

--- Comment #3 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> Martin, maybe you can try moving late sink to before the last phiopt pass.

If you mean the following then unfortunately that has not helped.

diff --git a/gcc/passes.def b/gcc/passes.def
index d7a1f8c97a6..5eb70cd2cd8 100644
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -347,10 +347,10 @@ along with GCC; see the file COPYING3.  If not see
       /* After late CD DCE we rewrite no longer addressed locals into SSA
         form if possible.  */
       NEXT_PASS (pass_forwprop);
+      NEXT_PASS (pass_sink_code);
       NEXT_PASS (pass_phiopt, false /* early_p */);
       NEXT_PASS (pass_fold_builtins);
       NEXT_PASS (pass_optimize_widening_mul);
-      NEXT_PASS (pass_sink_code);
       NEXT_PASS (pass_store_merging);
       NEXT_PASS (pass_tail_calls);
       /* If DCE is not run before checking for uninitialized uses,


...I'll have a very brief look at what is actually happening just so that I
have more reasons to believe this is not a code placement issue again.


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