[PATCH 2/9] [doloop] Correct extracting loop exit condition

[zhroma]

This patch fixes the compiler segfault found while regtesting trunk with SMS on
IA64 platform.  Segfault happens on test gcc.dg/pr45259.c with -fmodulo-sched
enabled.  The following jump instruction is given as argument for
doloop_condition_get function:
(jump_insn 86 85 88 7 (set (pc)
        (reg/f:DI 403)) 339 {indirect_jump}
     (expr_list:REG_DEAD (reg/f:DI 403)
        (nil)))
The patch adds checking for the form of comparison instruction before
extracting loop exit condition.

2011-07-20  Roman Zhuykov  <zhr...@ispras.ru>
        * loop-doloop.c (doloop_condition_get): Correctly check
        the form of comparison instruction.
---
 gcc/loop-doloop.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/gcc/loop-doloop.c b/gcc/loop-doloop.c
index f8429c4..dfc4a16 100644
--- a/gcc/loop-doloop.c
+++ b/gcc/loop-doloop.c
@@ -153,6 +153,8 @@ doloop_condition_get (rtx doloop_pat)
       else
         inc = PATTERN (prev_insn);
       /* We expect the condition to be of the form (reg != 0)  */
+      if (GET_CODE (cmp) != SET || GET_CODE (SET_SRC (cmp)) != IF_THEN_ELSE)
+       return 0;
       cond = XEXP (SET_SRC (cmp), 0);
       if (GET_CODE (cond) != NE || XEXP (cond, 1) != const0_rtx)
         return 0;
-- 
Roman Zhuykov
zhr...@ispras.ru