[gcc r12-9480] PR rtl-optimization/106421: ICE in bypass_block from non-local goto.

[Richard Biener <rguenth@gcc.gnu.org>]

https://gcc.gnu.org/g:0a5fb0ee337b824224a2c13b76fd682b62e6d314

commit r12-9480-g0a5fb0ee337b824224a2c13b76fd682b62e6d314
Author: Roger Sayle <roger@nextmovesoftware.com>
Date:   Tue Jan 10 14:05:46 2023 +0000

    PR rtl-optimization/106421: ICE in bypass_block from non-local goto.
    
    This patch fixes PR rtl-optimization/106421, an ICE-on-valid (but
    undefined) regression.  The fix, as proposed by Richard Biener, is to
    defend against BLOCK_FOR_INSN returning NULL in cprop's bypass_block.
    
    2023-01-10  Roger Sayle  <roger@nextmovesoftware.com>
    
    gcc/ChangeLog
            PR rtl-optimization/106421
            * cprop.cc (bypass_block): Check that DEST is local to this
            function (non-NULL) before calling find_edge.
    
    gcc/testsuite/ChangeLog
            PR rtl-optimization/106421
            * gcc.dg/pr106421.c: New test case.
    
    (cherry picked from commit 851e1ba03f9de699a754dd8648fc151c3e26d697)

Diff:
---
 gcc/cprop.cc                    |  9 ++++++---
 gcc/testsuite/gcc.dg/pr106421.c | 13 +++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/gcc/cprop.cc b/gcc/cprop.cc
index cf01c2d79a9..2a99553a5a5 100644
--- a/gcc/cprop.cc
+++ b/gcc/cprop.cc
@@ -1622,9 +1622,12 @@ bypass_block (basic_block bb, rtx_insn *setcc, rtx_insn *jump)
 	    {
 	      dest = BLOCK_FOR_INSN (XEXP (new_rtx, 0));
 	      /* Don't bypass edges containing instructions.  */
-	      edest = find_edge (bb, dest);
-	      if (edest && edest->insns.r)
-		dest = NULL;
+	      if (dest)
+		{
+		  edest = find_edge (bb, dest);
+		  if (edest && edest->insns.r)
+		    dest = NULL;
+		}
 	    }
 	  else
 	    dest = NULL;
diff --git a/gcc/testsuite/gcc.dg/pr106421.c b/gcc/testsuite/gcc.dg/pr106421.c
new file mode 100644
index 00000000000..73e522afc10
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106421.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int main(int argc, char **argv)
+{
+	__label__ loop, end;
+	void jmp(int c) { goto *(c ? &&loop : &&end); }
+loop:
+	jmp(argc < 0);
+end:
+	return 0;
+}
+