[PATCH] Fix ICE in redirect_jump_1 (PR inline-asm/63282)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

On the following testcase, dead_or_predicable decides to call
redirect_jump_1 on asm goto which has more than one label, but the
bb still has just two successors (one of the labels points to
code label at the start of the fallthru bb) and redirect_jump_1
ICEs on that.

Usually dead_or_predicable fails if !any_condjump_p, but there
is a shortcut (goto no_body) that bypasses that.

I think it doesn't really make sense to allow anything but normal
conditional jumps here, so the first patch just gives up in that
case.  Have done instrumented bootstrap on
{i?86,x86_64,aarch64,armv7hl,ppc64,ppc64le,s390,s390x}-linux
with this and the added goto cancel didn't trigger in any of the
bootstraps, and triggered only on 1-3 testcases in the testsuite
which all had asm goto in them (one of them this newly added
testcase).

Alternately, the second patch turns an assert in redirect_jump_1
into return 0, so it will fail (that also fixes the testcase).
With that patch alone, I'm worried about dead_or_predicable calling
invert_jump_1 on asm goto, which I can't understand how it would work
(there is no way how the "condition" can be inverted).  So, if
the second patch is preferable, I think dead_or_predicable should
still goto cancel if (reversep && !any_condjump_p (jump)).  Or
invert_jump_1 should fail early if !any_condjump_p.  Or both
of the patches could be applied together as is (of course, testcase
just from one of those).

2014-09-29  Jakub Jelinek  <jakub@redhat.com>

	PR inline-asm/63282
	* ifcvt.c (dead_or_predicable): Don't call redirect_jump_1
	or invert_jump_1 if jump isn't any_condjump_p.

	* gcc.c-torture/compile/pr63282.c: New test.

--- gcc/ifcvt.c.jj	2014-09-12 09:29:21.000000000 +0200
+++ gcc/ifcvt.c	2014-09-26 20:50:08.610965141 +0200
@@ -4357,6 +4357,9 @@ dead_or_predicable (basic_block test_bb,
   old_dest = JUMP_LABEL (jump);
   if (other_bb != new_dest)
     {
+      if (!any_condjump_p (jump))
+	goto cancel;
+
       if (JUMP_P (BB_END (dest_edge->src)))
 	new_dest_label = JUMP_LABEL (BB_END (dest_edge->src));
       else if (new_dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
--- gcc/testsuite/gcc.c-torture/compile/pr63282.c.jj	2014-09-26 20:51:40.999482179 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr63282.c	2014-09-26 20:51:43.882467325 +0200
@@ -0,0 +1,13 @@
+/* PR inline-asm/63282 */
+
+void bar (void);
+
+void
+foo (void)
+{
+  asm volatile goto ("" : : : : a, b);
+a:
+  bar ();
+b:
+  return;
+}

	Jakub

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