diff mbox

[PR66638] Fix assertion failure by skip the case.

Message ID 000c01d0afff$b937fd80$2ba7f880$@arm.com
State New
Headers show

Commit Message

Bin Cheng June 26, 2015, 11:03 a.m. UTC 
Hi,
This patch fixes GCC's profiled bootstrap failure.  As comment added by in
patch, it may still be possible to prove no overflow information for some
scev, unfortunately it's a rare case observed during GCC profiled bootstrap.
So for now I just skip it.

Is this OK?

Thanks,
bin

2015-06-26  Bin Cheng  <bin.cheng@arm.com>

	PR bootstrap/66638
	* tree-ssa-loop-niter.c (loop_exits_before_overflow): Skip if
	assertion failed.  Remove assertion itself.

Comments

Richard Biener June 26, 2015, 11:06 a.m. UTC | #1 
On Fri, Jun 26, 2015 at 1:03 PM, Bin Cheng <bin.cheng@arm.com> wrote:
> Hi,
> This patch fixes GCC's profiled bootstrap failure.  As comment added by in
> patch, it may still be possible to prove no overflow information for some
> scev, unfortunately it's a rare case observed during GCC profiled bootstrap.
> So for now I just skip it.
>
> Is this OK?

Ok.

Thanks,
Richard.

> Thanks,
> bin
>
> 2015-06-26  Bin Cheng  <bin.cheng@arm.com>
>
>         PR bootstrap/66638
>         * tree-ssa-loop-niter.c (loop_exits_before_overflow): Skip if
>         assertion failed.  Remove assertion itself.
>
diff mbox

Patch

Index: gcc/tree-ssa-loop-niter.c
===================================================================
--- gcc/tree-ssa-loop-niter.c	(revision 224827)
+++ gcc/tree-ssa-loop-niter.c	(working copy)
@@ -3955,7 +3955,21 @@  loop_exits_before_overflow (tree base, tree step,
 	if (!CONVERT_EXPR_P (e) || !operand_equal_p (e, unsigned_base, 0))
 	  continue;
 	e = TREE_OPERAND (e, 0);
-	gcc_assert (operand_equal_p (e, base, 0));
+	/* It may still be possible to prove no overflow even if condition
+	   "operand_equal_p (e, base, 0)" isn't satisfied here, like below
+	   example:
+
+	     e             : ssa_var                 ; unsigned long type
+	     base          : (int) ssa_var
+	     unsigned_base : (unsigned int) ssa_var
+
+	   Unfortunately this is a rare case observed during GCC profiled
+	   bootstrap.  See PR66638 for more information.
+
+	   For now, we just skip the possibility.  */
+	if (!operand_equal_p (e, base, 0))
+	  continue;
+
 	if (tree_int_cst_sign_bit (step))
 	  {
 	    code = LT_EXPR;