re PR target/51244 ([SH] Inefficient conditional branch and code around T bit)

gcc/
	PR target/51244
	* config/sh/sh.c (sh_eval_treg_value): Handle t_reg_operand and
	negt_reg_operand cases.
	* config/sh/sh.md (*cset_zero): Likewise by using cbranch_treg_value
	predicate.
	* config/sh/predicates.md (cbranch_treg_value): Simplify.

From-SVN: r210535

gcc/ChangeLog

 2014-05-16  Oleg Endo  <olegendo@gcc.gnu.org>
 
+	PR target/51244
+	* config/sh/sh.c (sh_eval_treg_value): Handle t_reg_operand and
+	negt_reg_operand cases.
+	* config/sh/sh.md (*cset_zero): Likewise by using cbranch_treg_value
+	predicate.
+	* config/sh/predicates.md (cbranch_treg_value): Simplify.
+
+2014-05-16  Oleg Endo  <olegendo@gcc.gnu.org>
+
 	* config/sh/sh.c (sh_option_override): Set branch cost to 2 for all
 	target variants.
 

gcc/config/sh/predicates.md

@@ -1119,10 +1119,8 @@
 ;; A predicate that returns true if OP is a valid construct around the T bit
 ;; that can be used as an operand for conditional branches.
 (define_predicate "cbranch_treg_value"
-  (match_code "eq,ne,reg,subreg,xor,sign_extend,zero_extend")
-{
-  return sh_eval_treg_value (op) >= 0;
-})
+  (and (match_code "eq,ne,reg,subreg,xor,sign_extend,zero_extend")
+       (match_test "sh_eval_treg_value (op) >= 0")))
 
 ;; Returns true if OP is arith_reg_operand or t_reg_operand.
 (define_predicate "arith_reg_or_t_reg_operand"

gcc/config/sh/sh.c

@@ -2250,7 +2250,12 @@ expand_cbranchdi4 (rtx *operands, enum rtx_code comparison)
 int
 sh_eval_treg_value (rtx op)
 {
-  enum rtx_code code = GET_CODE (op);
+  if (t_reg_operand (op, GET_MODE (op)))
+    return 1;
+  if (negt_reg_operand (op, GET_MODE (op)))
+    return 0;
+
+  rtx_code code = GET_CODE (op);
   if ((code != EQ && code != NE) || !CONST_INT_P (XEXP (op, 1)))
     return -1;
 

gcc/config/sh/sh.md

@@ -11624,14 +11624,22 @@ label:
 
 (define_insn "*cset_zero"
   [(set (match_operand:SI 0 "arith_reg_dest" "=r")
-	(if_then_else:SI (match_operand:SI 1 "t_reg_operand")
+	(if_then_else:SI (match_operand:SI 1 "cbranch_treg_value")
 			 (match_operand:SI 2 "arith_reg_operand" "0")
 			 (const_int 0)))]
   "TARGET_SH1 && TARGET_ZDCBRANCH"
 {
-  return       "bt	0f"	"\n"
-	 "	mov	#0,%0"	"\n"
-	 "0:";
+  int tval = sh_eval_treg_value (operands[1]);
+  if (tval == true)
+    return     "bt	0f"	"\n"
+	   "	mov	#0,%0"	"\n"
+	   "0:";
+  else if (tval == false)
+    return     "bf	0f"	"\n"
+	   "	mov	#0,%0"	"\n"
+	   "0:";
+  else
+    gcc_unreachable ();
 }
   [(set_attr "type" "arith") ;; poor approximation
    (set_attr "length" "4")])