[gcc r13-2664] tree-optimization/106938 - cleanup abnormal edges after inlining

[gcc r13-2664] tree-optimization/106938 - cleanup abnormal edges after inlining

[Richard Biener]

https://gcc.gnu.org/g:cd14c97cd92ca11c66ee3d8dc4dd543c5aa8e024

commit r13-2664-gcd14c97cd92ca11c66ee3d8dc4dd543c5aa8e024
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Sep 14 13:53:56 2022 +0200

    tree-optimization/106938 - cleanup abnormal edges after inlining
    
    After inlining and IPA transforms we run fixup_cfg to fixup CFG
    effects in other functions.  But that fails to clean abnormal
    edges from non-pure/const calls which might no longer be necessary
    when ->calls_setjmp is false.  The following ensures this happens
    and refactors things so we call EH/abnormal cleanup only on the
    last stmt in a block.
    
            PR tree-optimization/106938
            * tree-cfg.cc (execute_fixup_cfg): Purge dead abnormal
            edges for all last stmts in a block.  Do EH cleanup
            only on the last stmt in a block.
    
            * gcc.dg/pr106938.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/pr106938.c | 36 ++++++++++++++++++++++++++++++++++++
 gcc/tree-cfg.cc                 | 13 +++++++------
 2 files changed, 43 insertions(+), 6 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/pr106938.c b/gcc/testsuite/gcc.dg/pr106938.c
new file mode 100644
index 00000000000..7365a8c29fb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106938.c
@@ -0,0 +1,36 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fno-ipa-pure-const -fno-tree-ccp -Wuninitialized" } */
+
+int n;
+
+void
+undefined (void);
+
+__attribute__ ((returns_twice)) int
+zero (void)
+{
+  return 0;
+}
+
+void
+bar (int)
+{
+  int i;
+
+  for (i = 0; i < -1; ++i)
+    n = 0;
+}
+
+__attribute__ ((simd)) void
+foo (void)
+{
+  int uninitialized;
+
+  undefined ();
+
+  while (uninitialized < 1) /* { dg-warning "uninitialized" } */
+    {
+      bar (zero ());
+      ++uninitialized;
+    }
+}
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 41ce1b29d17..53be0c2ec5d 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -9836,16 +9836,12 @@ execute_fixup_cfg (void)
 	      int flags = gimple_call_flags (stmt);
 	      if (flags & (ECF_CONST | ECF_PURE | ECF_LOOPING_CONST_OR_PURE))
 		{
-		  if (gimple_purge_dead_abnormal_call_edges (bb))
-		    todo |= TODO_cleanup_cfg;
-
 		  if (gimple_in_ssa_p (cfun))
 		    {
 		      todo |= TODO_update_ssa | TODO_cleanup_cfg;
 		      update_stmt (stmt);
 		    }
 		}
-
 	      if (flags & ECF_NORETURN
 		  && fixup_noreturn_call (stmt))
 		todo |= TODO_cleanup_cfg;
@@ -9875,10 +9871,15 @@ execute_fixup_cfg (void)
 		}
 	    }
 
-	  if (maybe_clean_eh_stmt (stmt)
+	  gsi_next (&gsi);
+	}
+      if (gimple *last = last_stmt (bb))
+	{
+	  if (maybe_clean_eh_stmt (last)
 	      && gimple_purge_dead_eh_edges (bb))
 	    todo |= TODO_cleanup_cfg;
-	  gsi_next (&gsi);
+	  if (gimple_purge_dead_abnormal_call_edges (bb))
+	    todo |= TODO_cleanup_cfg;
 	}
 
       /* If we have a basic block with no successors that does not