i386.md: Add peephole to merge successive stack adjusts.

	* config/i386/i386.md: Add peephole to merge successive stack
	adjusts.

From-SVN: r31443

gcc/ChangeLog

+2000-01-16  Zack Weinberg  <zack@wolery.cumb.org>
+
+	* config/i386/i386.md: Add peephole to merge successive stack
+	adjusts. 
+
 Sat Jan 15 15:41:14 EST 2000  John Wehle  (john@feith.com)
 
 	* gcse.c (insert_insn_end_bb): Use emit_block_insn_before

gcc/config/i386/i386.md

@@ -8947,6 +8947,25 @@
   [(parallel [(set (match_dup 0) (ashift:SI (match_dup 0) (match_dup 2)))
 	      (clobber (reg:CC 17))])]
   "operands[2] = GEN_INT (exact_log2 (INTVAL (operands[1])));")
+
+;; Merge two successive stack adjusts.  The combiner doesn't know how
+;; to do this, and doesn't see all of them.
+;; (reg:SI 7) is %esp.
+(define_peephole2
+  [(parallel[
+    (set (reg:SI 7)
+	 (plus:SI (reg:SI 7) (match_operand:SI 0 "const_int_operand" "")))
+    (clobber (reg:CC 17))])
+   (parallel[
+    (set (reg:SI 7)
+	 (plus:SI (reg:SI 7) (match_operand:SI 1 "const_int_operand" "")))
+    (clobber (reg:CC 17))])]
+  ""
+  [(parallel[
+    (set (reg:SI 7)
+	 (plus:SI (reg:SI 7) (match_dup 2)))
+    (clobber (reg:CC 17))])]
+  "operands[2] = GEN_INT (INTVAL (operands[0]) + INTVAL (operands[1]));")
 
 ;; Call-value patterns last so that the wildcard operand does not
 ;; disrupt insn-recog's switch tables.