optabs.c (widen_operand): Only call convert_modes for promoted SUBREG if signedness matches.

	* optabs.c (widen_operand): Only call convert_modes for
	promoted SUBREG if signedness matches.
	* config/alpha/alpha.md (*addsi_se2, *subsi_se2): New patterns.

From-SVN: r50004

gcc/ChangeLog

+Sun Feb 24 07:41:31 2002  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
+
+	* optabs.c (widen_operand): Only call convert_modes for
+	promoted SUBREG if signedness matches.
+	* config/alpha/alpha.md (*addsi_se2, *subsi_se2): New patterns.
+
 2002-02-23  Neil Booth  <neil@daikokuya.demon.co.uk>
 
 	* cpplib.c (glue_header_name): Use local buffer to build up

gcc/config/alpha/alpha.md

@@ -564,6 +564,17 @@ fadd,fmul,fcpys,fdiv,fsqrt,misc,mvi,ftoi,itof,multi"
    addl %r1,%2,%0
    subl %r1,%n2,%0")
 
+(define_insn "*addsi_se2"
+  [(set (match_operand:DI 0 "register_operand" "=r,r")
+	(sign_extend:DI
+	 (subreg:SI (plus:DI (match_operand:DI 1 "reg_or_0_operand" "%rJ,rJ")
+			     (match_operand:DI 2 "sext_add_operand" "rI,O"))
+		    0)))]
+  ""
+  "@
+   addl %r1,%2,%0
+   subl %r1,%n2,%0")
+
 (define_split
   [(set (match_operand:DI 0 "register_operand" "")
 	(sign_extend:DI
@@ -844,6 +855,15 @@ fadd,fmul,fcpys,fdiv,fsqrt,misc,mvi,ftoi,itof,multi"
   ""
   "subl %r1,%2,%0")
 
+(define_insn "*subsi_se2"
+  [(set (match_operand:DI 0 "register_operand" "=r")
+	(sign_extend:DI
+	 (subreg:SI (minus:DI (match_operand:DI 1 "reg_or_0_operand" "rJ")
+			      (match_operand:DI 2 "reg_or_8bit_operand" "rI"))
+		    0)))]
+  ""
+  "subl %r1,%2,%0")
+
 (define_insn "subvsi3"
   [(set (match_operand:SI 0 "register_operand" "=r")
 	(minus:SI (match_operand:SI 1 "reg_or_0_operand" "rJ")

gcc/optabs.c

@@ -191,7 +191,8 @@ widen_operand (op, mode, oldmode, unsignedp, no_extend)
      do so.  */
   if (! no_extend
       || GET_MODE (op) == VOIDmode
-      || (GET_CODE (op) == SUBREG && SUBREG_PROMOTED_VAR_P (op)))
+      || (GET_CODE (op) == SUBREG && SUBREG_PROMOTED_VAR_P (op)
+	  && SUBREG_PROMOTED_UNSIGNED_P (op) == unsignedp))
     return convert_modes (mode, oldmode, op, unsignedp);
 
   /* If MODE is no wider than a single word, we return a paradoxical