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

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

[Roger Sayle]

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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.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32},
with no new failures.  Ok for mainline?


2023-01-09  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.


Thanks in advance,
Roger
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diff --git a/gcc/cprop.cc b/gcc/cprop.cc
index 5b203ec..6ec0bda 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 0000000..73e522a
--- /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;
+}
+

Re: [PATCH] PR rtl-optimization/106421: ICE in bypass_block from non-local goto.

[Richard Biener]

On Mon, Jan 9, 2023 at 8:50 PM Roger Sayle <roger@nextmovesoftware.com> wrote:
>
>
> 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.
>
> This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> and make -k check, both with and without --target_board=unix{-m32},
> with no new failures.  Ok for mainline?

OK.

>
> 2023-01-09  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.
>
>
> Thanks in advance,
> Roger
> --
>