Avoid conservative behavior in REE by allowing removal of redundant extends when...

Avoid conservative behavior in REE by allowing removal of redundant extends
when the def feeds another extend with a different mode. This works because
in merge_def_and_ext only calls combine_set_extension if the candidate for
removal has a wider mode than the def extend's mode, otherwise the def extend
mode is preserved. In combine_set_extension the def is modified to use the
wider candidate's mode.

2012-10-26  Teresa Johnson  <tejohnson@google.com>

	* ree.c (add_removable_extension): Remove unnecessary
	mode check with other extension.
	* testsuite/gcc.c-torture/execute/20111227-2.c: New test.
	* testsuite/gcc.c-torture/execute/20111227-3.c: Ditto.

From-SVN: r192850

1 files changed, 1 insertions, 1 deletions

diff --git a/gcc/ree.c b/gcc/ree.c
index 167efa3..a2ede97 100644
--- a/gcc/ree.c
+++ b/gcc/ree.c
@@ -803,7 +803,7 @@ add_removable_extension (const_rtx expr, rtx insn,
       for (def = defs; def; def = def->next)
 	if ((idx = def_map[INSN_UID(DF_REF_INSN (def->ref))])
 	    && (cand = &VEC_index (ext_cand, *insn_list, idx - 1))
-	    && (cand->code != code || cand->mode != mode))
+	    && cand->code != code)
 	  {
 	    if (dump_file)
 	      {