ifcvt: Fall through to NCE if getting the CE condition failed

If getting the condition for conditional execution has failed then fall
through and try the non-conditional execution approach instead rather
than giving up with dead code elimination altogether, for a better code
structure if nothing else.

The case may well now be that whenever `cond_exec_get_condition' fails
`noce_get_condition' will as well, however in that case no change in
semantics will result.  If they ever diverge, then someone will have to
chase this place.

	gcc/
	* ifcvt.c (dead_or_predicable) [!IFCVT_MODIFY_TESTS]: Fall
	through to the non-conditional execution case if getting the
	condition for conditional execution has failed.

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index b467eb5..4de7bb9 100644 (file)
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -5193,7 +5193,7 @@ dead_or_predicable (basic_block test_bb, basic_block merge_bb,
 
       cond = cond_exec_get_condition (jump);
       if (! cond)
-       return FALSE;
+       goto nce;
 
       rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
       profile_probability prob_val