tree-optimization/104263 - avoid retaining abnormal edges for non-call/goto stmts

This removes a premature optimization from
gimple_purge_dead_abnormal_call_edges which, after eliding the
last setjmp (or computed goto) statement from a function and
thus clearing cfun->calls_setjmp, leaves us with the abnormal
edges from other calls that are elided for example via inlining
or DCE.  That's a CFG / IL combination that should be impossible
(not addressing the fact that with cfun->calls_setjmp and
cfun->has_nonlocal_label cleared we should not have any abnormal
edge at all).

For the testcase in the PR this means that IPA inlining will
remove the abormal edges from the block after inlining the call
the edge was coming from.

2022-01-28  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/104263
	* tree-cfg.cc (gimple_purge_dead_abnormal_call_edges):
	Purge edges also when !cfun->has_nonlocal_label
	and !cfun->calls_setjmp.

	* gcc.dg/tree-ssa/inline-13.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/inline-13.c b/gcc/testsuite/gcc.dg/tree-ssa/inline-13.c
new file mode 100644 (file)
index 0000000..94d8a9c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/inline-13.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-early-inlining -fdump-tree-fixup_cfg3" } */
+
+int n;
+
+static int
+bar (void)
+{
+  int a;
+
+  n = 0;
+  a = 0;
+
+  return n;
+}
+
+__attribute__ ((pure, returns_twice)) int
+foo (void)
+{
+  n = bar () + 1;
+  foo ();
+
+  return 0;
+}
+
+/* Abnormal edges should be properly elided after IPA inlining of bar.  */
+/* { dg-final { scan-tree-dump-times "bb" 1 "fixup_cfg3" } } */

diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 77178a6..efd1033 100644 (file)
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -8915,10 +8915,6 @@ gimple_purge_dead_abnormal_call_edges (basic_block bb)
   edge_iterator ei;
   gimple *stmt = last_stmt (bb);
 
-  if (!cfun->has_nonlocal_label
-      && !cfun->calls_setjmp)
-    return false;
-
   if (stmt && stmt_can_make_abnormal_goto (stmt))
     return false;