This is the failure of the new assertion added in the REG_ARGS_SIZE case of
distribute_notes in the combiner on a degenerated case (complete folding of a
dynamic stack allocation). Fixed by dropping the note if the resulting insn
is a no-op move.
Tested on i586-suse-linux, applied on the mainline.
2011-10-16 Eric Botcazou <ebotca...@adacore.com>
PR rtl-optimization/50615
* combine.c (distribute_notes) <REG_ARGS_SIZE>: Skip if I3 is a no-op.
2011-10-16 Eric Botcazou <ebotca...@adacore.com>
* gcc.dg/vla-23.c: New test.
--
Eric Botcazou
Index: combine.c
===================================================================
--- combine.c (revision 179844)
+++ combine.c (working copy)
@@ -13274,13 +13274,14 @@ distribute_notes (rtx notes, rtx from_in
break;
case REG_ARGS_SIZE:
- {
- /* ??? How to distribute between i3-i1. Assume i3 contains the
- entire adjustment. Assert i3 contains at least some adjust. */
- int old_size, args_size = INTVAL (XEXP (note, 0));
- old_size = fixup_args_size_notes (PREV_INSN (i3), i3, args_size);
- gcc_assert (old_size != args_size);
- }
+ /* ??? How to distribute between i3-i1. Assume i3 contains the
+ entire adjustment. Assert i3 contains at least some adjust. */
+ if (!noop_move_p (i3))
+ {
+ int old_size, args_size = INTVAL (XEXP (note, 0));
+ old_size = fixup_args_size_notes (PREV_INSN (i3), i3, args_size);
+ gcc_assert (old_size != args_size);
+ }
break;
case REG_NORETURN:
/* PR rtl-optimization/50615 */
/* Testcase by Zdenek Sojka <zso...@seznam.cz> */
/* { dg-do compile } */
/* { dg-options "-O --param max-cse-insns=1" } */
int
foo (int a)
{
if (!a)
return 1;
{
int s[a];
return 0;
}
}
