[gcc r14-4936] set hardcmp eh probs

[gcc r14-4936] set hardcmp eh probs

[Alexandre Oliva]

https://gcc.gnu.org/g:33d38b431cced81e575b1d17d36cb9e43d64b02b

commit r14-4936-g33d38b431cced81e575b1d17d36cb9e43d64b02b
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Thu Oct 26 03:06:09 2023 -0300

    set hardcmp eh probs
    
    Set execution count of EH blocks, and probability of EH edges.
    
    
    for  gcc/ChangeLog
    
            PR tree-optimization/111520
            * gimple-harden-conditionals.cc
            (pass_harden_compares::execute): Set EH edge probability and
            EH block execution count.
    
    for  gcc/testsuite/ChangeLog
    
            PR tree-optimization/111520
            * g++.dg/torture/harden-comp-pr111520.cc: New.

Diff:
---
 gcc/gimple-harden-conditionals.cc                    | 12 +++++++++++-
 gcc/testsuite/g++.dg/torture/harden-comp-pr111520.cc | 17 +++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index 1999e827a04c..bded28898506 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -580,11 +580,21 @@ pass_harden_compares::execute (function *fun)
 	  if (throwing_compare_p)
 	    {
 	      add_stmt_to_eh_lp (asgnck, lookup_stmt_eh_lp (asgn));
-	      make_eh_edge (asgnck);
+	      edge eh = make_eh_edge (asgnck);
+	      /* This compare looks like it could raise an exception,
+		 but it's dominated by the original compare, that
+		 would raise an exception first, so the EH edge from
+		 this one is never really taken.  */
+	      eh->probability = profile_probability::never ();
+	      if (eh->dest->count.initialized_p ())
+		eh->dest->count += eh->count ();
+	      else
+		eh->dest->count = eh->count ();
 
 	      edge ckeh;
 	      basic_block nbb = split_edge (non_eh_succ_edge
 					    (gimple_bb (asgnck), &ckeh));
+	      gcc_checking_assert (eh == ckeh);
 	      gsi_split = gsi_start_bb (nbb);
 
 	      if (dump_file)
diff --git a/gcc/testsuite/g++.dg/torture/harden-comp-pr111520.cc b/gcc/testsuite/g++.dg/torture/harden-comp-pr111520.cc
new file mode 100644
index 000000000000..b4381b4d84ec
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/harden-comp-pr111520.cc
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-fharden-compares -fsignaling-nans -fnon-call-exceptions" } */
+
+struct S
+{
+  S (bool);
+  ~S ();
+};
+
+float f;
+
+void
+foo ()
+{
+  S a = 0;
+  S b = f;
+}