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-rw-r--r--gcc/ChangeLog8
-rw-r--r--gcc/compare-elim.c22
2 files changed, 25 insertions, 5 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4daecb4..c7d8eac 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2012-04-25 Uros Bizjak <ubizjak@gmail.com>
+
+ * compare-elim.c (try_eliminate_compare): Also handle operands with
+ implicit extensions.
+
2012-04-25 Alan Modra <amodra@gmail.com>
* config/rs6000/rs6000 (SAVE_INLINE_VRS, REST_INLINE_VRS,
@@ -205,8 +210,7 @@
2012-04-24 Jakub Jelinek <jakub@redhat.com>
PR middle-end/53084
- * varasm.c (compute_reloc_for_constant): Handle ADDR_EXPR
- of MEM_REF.
+ * varasm.c (compute_reloc_for_constant): Handle ADDR_EXPR of MEM_REF.
(output_addressed_constants): Likewise.
PR middle-end/52999
diff --git a/gcc/compare-elim.c b/gcc/compare-elim.c
index 5157e76..f11a724 100644
--- a/gcc/compare-elim.c
+++ b/gcc/compare-elim.c
@@ -563,10 +563,26 @@ try_eliminate_compare (struct comparison *cmp)
Validate that PREV_CLOBBER itself does in fact refer to IN_A. Do
recall that we've already validated the shape of PREV_CLOBBER. */
x = XVECEXP (PATTERN (insn), 0, 0);
- if (!rtx_equal_p (SET_DEST (x), in_a))
+ if (rtx_equal_p (SET_DEST (x), in_a))
+ cmp_src = SET_SRC (x);
+
+ /* Also check operations with implicit extensions, e.g.:
+ [(set (reg:DI)
+ (zero_extend:DI (plus:SI (reg:SI)(reg:SI))))
+ (set (reg:CCZ flags)
+ (compare:CCZ
+ (plus:SI (reg:SI)(reg:SI))
+ (const_int 0)))] */
+ else if (REG_P (SET_DEST (x))
+ && REG_P (in_a)
+ && REGNO (SET_DEST (x)) == REGNO (in_a)
+ && (GET_CODE (SET_SRC (x)) == ZERO_EXTEND
+ || GET_CODE (SET_SRC (x)) == SIGN_EXTEND)
+ && GET_MODE (XEXP (SET_SRC (x), 0)) == GET_MODE (in_a))
+ cmp_src = XEXP (SET_SRC (x), 0);
+ else
return false;
- cmp_src = SET_SRC (x);
-
+
/* Determine if we ought to use a different CC_MODE here. */
flags = maybe_select_cc_mode (cmp, cmp_src, cmp->in_b);
if (flags == NULL)