diff mbox series

tree-optimization/109331 - make sure to clean up the CFG after forwprop

Message ID 20230329115611.9E6213858C2B@sourceware.org
State New
Headers show
Series tree-optimization/109331 - make sure to clean up the CFG after forwprop | expand

Commit Message

Richard Biener March 29, 2023, 11:55 a.m. UTC 
When forwprop discovers unreachable code or makes decisions based
on unreachable edges make sure to cleanup the CFG since otherwise
SSA form can become invalid.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/109331
	* tree-ssa-forwprop.cc (pass_forwprop::execute): When we
	discover a taken edge make sure to cleanup the CFG.

	* gcc.dg/torture/pr109331.c: New testcase.
---
 gcc/testsuite/gcc.dg/torture/pr109331.c | 16 ++++++++++++++++
 gcc/tree-ssa-forwprop.cc                |  6 +++++-
 2 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/torture/pr109331.c
diff mbox series

Patch

diff --git a/gcc/testsuite/gcc.dg/torture/pr109331.c b/gcc/testsuite/gcc.dg/torture/pr109331.c
new file mode 100644
index 00000000000..72c57b9b74c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr109331.c
@@ -0,0 +1,16 @@ 
+/* { dg-do compile } */
+
+char *ustol_dpp;
+void ustol(int flags)
+{
+  char *s;
+  if (s)
+    flags |= 3;
+  switch (flags & 3)
+  case 3:
+    while (*s)
+    case '+':
+      ++s;
+  if (flags)
+    ustol_dpp = s;
+}
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index bb0fa306312..9b567440ba4 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -4046,7 +4046,11 @@  pass_forwprop::execute (function *fun)
 
       /* Mark outgoing exectuable edges.  */
       if (edge e = find_taken_edge (bb, NULL))
-	e->flags |= EDGE_EXECUTABLE;
+	{
+	  e->flags |= EDGE_EXECUTABLE;
+	  if (EDGE_COUNT (bb->succs) > 1)
+	    cfg_changed = true;
+	}
       else
 	{
 	  FOR_EACH_EDGE (e, ei, bb->succs)