diff mbox

Don't ICE trying to redirect abnormal edges during shrink-wrapping (PR rtl-optimization/51495)

Message ID 20111212172803.GU1957@tyan-ft48-01.lab.bos.redhat.com
State New
Headers show

Commit Message

Jakub Jelinek Dec. 12, 2011, 5:28 p.m. UTC 
Hi!

On this testcase we ICE starting from
http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=181188
because one of the basic blocks we add to bb_tail has EDGE_ABNORMAL
edge (computed goto) from a basic block that doesn't need prologue.
We try to duplicate the basic block and finally redirect that EDGE_ABNORMAL
edge, which ICEs.

Fixed by not putting basic blocks into bb_tail if they have complex edges
from basic blocks that don't need prologue.
In x8_64/i686 bootstraps/regtests this only affected compile/pr51495.c,
compile/pr28489.c, torture/pr42462.C and execute/980526-1.c testcases.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2011-12-12  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/51495
	* function.c (thread_prologue_and_epilogue_insns): Don't add
	to bb_tail basic blocks that have EDGE_COMPLEX predecessor edges
	from basic blocks not needing prologue.

	* gcc.c-torture/compile/pr51495.c: New test.


	Jakub

Comments

Richard Henderson Dec. 12, 2011, 8:48 p.m. UTC | #1 
On 12/12/2011 09:28 AM, Jakub Jelinek wrote:
> 	PR rtl-optimization/51495
> 	* function.c (thread_prologue_and_epilogue_insns): Don't add
> 	to bb_tail basic blocks that have EDGE_COMPLEX predecessor edges
> 	from basic blocks not needing prologue.
> 
> 	* gcc.c-torture/compile/pr51495.c: New test.

Ok.


r~
diff mbox

Patch

--- gcc/function.c.jj	2011-12-11 22:02:37.000000000 +0100
+++ gcc/function.c	2011-12-12 14:31:01.821624702 +0100
@@ -5956,9 +5956,22 @@  thread_prologue_and_epilogue_insns (void
 	  FOR_EACH_EDGE (e, ei, tmp_bb->preds)
 	    if (single_succ_p (e->src)
 		&& !bitmap_bit_p (&bb_on_list, e->src->index)
-		&& can_duplicate_block_p (e->src)
-		&& bitmap_set_bit (&bb_tail, e->src->index))
-	      VEC_quick_push (basic_block, vec, e->src);
+		&& can_duplicate_block_p (e->src))
+	      {
+		edge pe;
+		edge_iterator pei;
+
+		/* If there is predecessor of e->src which doesn't
+		   need prologue and the edge is complex,
+		   we might not be able to redirect the branch
+		   to a copy of e->src.  */
+		FOR_EACH_EDGE (pe, pei, e->src->preds)
+		  if ((pe->flags & EDGE_COMPLEX) != 0
+		      && !bitmap_bit_p (&bb_flags, pe->src->index))
+		    break;
+		if (pe == NULL && bitmap_set_bit (&bb_tail, e->src->index))
+		  VEC_quick_push (basic_block, vec, e->src);
+	      }
 	}
 
       /* Now walk backwards from every block that is marked as needing
--- gcc/testsuite/gcc.c-torture/compile/pr51495.c.jj	2011-12-12 14:32:45.047017210 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr51495.c	2011-12-12 14:32:15.000000000 +0100
@@ -0,0 +1,14 @@ 
+/* PR rtl-optimization/51495 */
+
+void bar (void);
+
+int
+foo (int i)
+{
+  static const void *const table[] = { &&begin, &&end };
+  goto *(table[i]);
+begin:
+  bar ();
+end:
+  return 0;
+}