Hello,

It seems that splitting multi-word insns before reload results in
slightly better code on average (according to CSiBE).  The attached
patch implements that.
Tested on rev. 204263 with
make -k -j4 check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m2a-single/-mb,-m4/-ml,-m4/-mb,-m4-single/
-ml,-m4-single/-mb,-m4a-single/-ml,-m4a-single/-mb}"

and no new failures.  However, as far as I recall there have been some
issues with this in the past, I just can't find/remember what it was
exactly.  Kaz, could you please run it through your test setup, too and
let me know if it's OK for trunk?

Thanks,
Oleg

gcc/ChangeLog:

        * config/sh/sh.md (adddi3): Remove empty constraints.  Remove 
        can_create_pseudo_p and arith_reg_operand check.
        (adddi3_compact, subdi3_compact, *negdi2): Remove constraints, 
        split before reload.
Index: gcc/config/sh/sh.md
===================================================================
--- gcc/config/sh/sh.md	(revision 204263)
+++ gcc/config/sh/sh.md	(working copy)
@@ -1747,15 +1747,13 @@
 ;; -------------------------------------------------------------------------
 
 (define_expand "adddi3"
-  [(set (match_operand:DI 0 "arith_reg_operand" "")
-	(plus:DI (match_operand:DI 1 "arith_reg_operand" "")
-		 (match_operand:DI 2 "arith_operand" "")))]
+  [(set (match_operand:DI 0 "arith_reg_operand")
+	(plus:DI (match_operand:DI 1 "arith_reg_operand")
+		 (match_operand:DI 2 "arith_operand")))]
   ""
 {
   if (TARGET_SH1)
     {
-      if (!can_create_pseudo_p () && ! arith_reg_operand (operands[2], DImode))
-	FAIL;
       operands[2] = force_reg (DImode, operands[2]);
       emit_insn (gen_adddi3_compact (operands[0], operands[1], operands[2]));
       DONE;
@@ -1794,22 +1792,22 @@
    (set_attr "highpart" "ignore")])
 
 (define_insn_and_split "adddi3_compact"
-  [(set (match_operand:DI 0 "arith_reg_dest" "=&r")
-	(plus:DI (match_operand:DI 1 "arith_reg_operand" "%0")
-		 (match_operand:DI 2 "arith_reg_operand" "r")))
+  [(set (match_operand:DI 0 "arith_reg_dest")
+	(plus:DI (match_operand:DI 1 "arith_reg_operand")
+		 (match_operand:DI 2 "arith_reg_operand")))
    (clobber (reg:SI T_REG))]
   "TARGET_SH1"
   "#"
-  "&& reload_completed"
+  "&& can_create_pseudo_p ()"
   [(const_int 0)]
 {
-  rtx high0 = gen_highpart (SImode, operands[0]);
-  rtx high2 = gen_highpart (SImode, operands[2]);
-  rtx low0 = gen_lowpart (SImode, operands[0]);
-
   emit_insn (gen_clrt ());
-  emit_insn (gen_addc (low0, low0, gen_lowpart (SImode, operands[2])));
-  emit_insn (gen_addc (high0, high0, high2));
+  emit_insn (gen_addc (gen_lowpart (SImode, operands[0]),
+		       gen_lowpart (SImode, operands[1]),
+		       gen_lowpart (SImode, operands[2])));
+  emit_insn (gen_addc (gen_highpart (SImode, operands[0]),
+		       gen_highpart (SImode, operands[1]),
+		       gen_highpart (SImode, operands[2])));
   DONE;
 })
 
@@ -2108,22 +2106,22 @@
    (set_attr "highpart" "ignore")])
 
 (define_insn_and_split "subdi3_compact"
-  [(set (match_operand:DI 0 "arith_reg_dest" "=&r")
-	(minus:DI (match_operand:DI 1 "arith_reg_operand" "0")
-		 (match_operand:DI 2 "arith_reg_operand" "r")))
+  [(set (match_operand:DI 0 "arith_reg_dest")
+	(minus:DI (match_operand:DI 1 "arith_reg_operand")
+		 (match_operand:DI 2 "arith_reg_operand")))
    (clobber (reg:SI T_REG))]
   "TARGET_SH1"
   "#"
-  "&& reload_completed"
+  "&& can_create_pseudo_p ()"
   [(const_int 0)]
 {
-  rtx high0 = gen_highpart (SImode, operands[0]);
-  rtx high2 = gen_highpart (SImode, operands[2]);
-  rtx low0 = gen_lowpart (SImode, operands[0]);
-
   emit_insn (gen_clrt ());
-  emit_insn (gen_subc (low0, low0, gen_lowpart (SImode, operands[2])));
-  emit_insn (gen_subc (high0, high0, high2));
+  emit_insn (gen_subc (gen_lowpart (SImode, operands[0]),
+		       gen_lowpart (SImode, operands[1]),
+		       gen_lowpart (SImode, operands[2])));
+  emit_insn (gen_subc (gen_highpart (SImode, operands[0]),
+		       gen_highpart (SImode, operands[1]),
+		       gen_highpart (SImode, operands[2])));
   DONE;
 })
 
@@ -5567,8 +5565,8 @@
   "sub	r63, %1, %0"
   [(set_attr "type" "arith_media")])
 
-;; Don't expand immediately because otherwise neg:DI (abs:DI) will not be
-;; combined.
+;; Don't split into individual negc insns immediately so that neg:DI (abs:DI)
+;; can be combined.
 (define_expand "negdi2"
   [(parallel [(set (match_operand:DI 0 "arith_reg_dest")
 		   (neg:DI (match_operand:DI 1 "arith_reg_operand")))
@@ -5576,12 +5574,12 @@
   "TARGET_SH1")
 
 (define_insn_and_split "*negdi2"
-  [(set (match_operand:DI 0 "arith_reg_dest" "=&r")
-	(neg:DI (match_operand:DI 1 "arith_reg_operand" "r")))
+  [(set (match_operand:DI 0 "arith_reg_dest")
+	(neg:DI (match_operand:DI 1 "arith_reg_operand")))
    (clobber (reg:SI T_REG))]
   "TARGET_SH1"
   "#"
-  "&& reload_completed"
+  "&& can_create_pseudo_p ()"
   [(const_int 0)]
 {
   emit_insn (gen_clrt ());

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