arm.md (arm_addsi3): New variant for Thumb2 16-bit ADD instruction.

	* arm.md (arm_addsi3): New variant for Thumb2 16-bit ADD instruction.
	* arm.c (thumb2_reorg): Don't convert an ADD instruction that's
	already 16 bits.

From-SVN: r190472

gcc/ChangeLog

+2012-08-17  Richard Earnshaw  <rearnsha@arm.com>
+
+	* arm.md (arm_addsi3): New variant for Thumb2 16-bit ADD instruction.
+	* arm.c (thumb2_reorg): Don't convert an ADD instruction that's
+	already 16 bits.
+
 2012-08-17  Richard Guenther  <rguenther@suse.de>
 
 	* hash-table.h (class hash_table): Use a descriptor template

gcc/config/arm/arm.c

@@ -13309,6 +13309,13 @@ thumb2_reorg (void)
 		  switch (GET_CODE (src))
 		    {
 		    case PLUS:
+		      /* Adding two registers and storing the result
+			 in the first source is already a 16-bit
+			 operation.  */
+		      if (rtx_equal_p (dst, op0)
+			  && register_operand (op1, SImode))
+			break;
+
 		      if (low_register_operand (op0, SImode))
 			{
 			  /* ADDS <Rd>,<Rn>,<Rm>  */

gcc/config/arm/arm.md

@@ -746,11 +746,12 @@
 ;;  (plus (reg rN) (reg sp)) into (reg rN).  In this case reload will
 ;; put the duplicated register first, and not try the commutative version.
 (define_insn_and_split "*arm_addsi3"
-  [(set (match_operand:SI          0 "s_register_operand" "=r, k,r,r, k, r, k,k,r, k, r")
-	(plus:SI (match_operand:SI 1 "s_register_operand" "%rk,k,r,rk,k, rk,k,r,rk,k, rk")
-		 (match_operand:SI 2 "reg_or_int_operand" "rI,rI,k,Pj,Pj,L, L,L,PJ,PJ,?n")))]
+  [(set (match_operand:SI          0 "s_register_operand" "=rk, r,k, r,r, k, r, k,k,r, k, r")
+	(plus:SI (match_operand:SI 1 "s_register_operand" "%0, rk,k, r,rk,k, rk,k,r,rk,k, rk")
+		 (match_operand:SI 2 "reg_or_int_operand" "rk, rI,rI,k,Pj,Pj,L, L,L,PJ,PJ,?n")))]
   "TARGET_32BIT"
   "@
+   add%?\\t%0, %0, %2
    add%?\\t%0, %1, %2
    add%?\\t%0, %1, %2
    add%?\\t%0, %2, %1
@@ -773,9 +774,9 @@
 		      operands[1], 0);
   DONE;
   "
-  [(set_attr "length" "4,4,4,4,4,4,4,4,4,4,16")
+  [(set_attr "length" "2,4,4,4,4,4,4,4,4,4,4,16")
    (set_attr "predicable" "yes")
-   (set_attr "arch" "*,*,*,t2,t2,*,*,a,t2,t2,*")]
+   (set_attr "arch" "t2,*,*,*,t2,t2,*,*,a,t2,t2,*")]
 )
 
 (define_insn_and_split "*thumb1_addsi3"