Re: [PATCH][ARM] Add support for ADDW and SUBW instructions

[Andrew Stubbs <ams@codesourcery.com>]

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On 16/06/11 10:13, Stubbs, Andrew wrote:
> On 02/06/11 11:36, Ramana Radhakrishnan wrote:
>> OK.
>
> I've not yet committed this patch because my final testing revealed an
> unexpected bootstrap failure. I'm still investigating.
>
> I'll commit or post a replacement soon ... ish.

Ok, it wasn't very soon, but I've now committed this patch.

In fact the bug was in my thumb2 replicated constants patch, so this one 
is committed unchanged.

Actual patch updated for current baseline attached.

Andrew

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2011-08-26  Andrew Stubbs  <ams@codesourcery.com>

	gcc/
	* config/arm/arm-protos.h (const_ok_for_op): Add prototype.
	* config/arm/arm.c (const_ok_for_op): Add support for addw/subw.
	Remove prototype. Remove static function type.
	* config/arm/arm.md (*arm_addsi3): Add addw/subw support.
	Add arch attribute.
	* config/arm/constraints.md (Pj, PJ): New constraints.

--- a/gcc/config/arm/arm-protos.h
+++ b/gcc/config/arm/arm-protos.h
@@ -47,6 +47,7 @@ extern bool arm_vector_mode_supported_p (enum machine_mode);
 extern bool arm_small_register_classes_for_mode_p (enum machine_mode);
 extern int arm_hard_regno_mode_ok (unsigned int, enum machine_mode);
 extern int const_ok_for_arm (HOST_WIDE_INT);
+extern int const_ok_for_op (HOST_WIDE_INT, enum rtx_code);
 extern int arm_split_constant (RTX_CODE, enum machine_mode, rtx,
 			       HOST_WIDE_INT, rtx, rtx, int);
 extern RTX_CODE arm_canonicalize_comparison (RTX_CODE, rtx *, rtx *);
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -82,7 +82,6 @@ inline static int thumb1_index_register_rtx_p (rtx, int);
 static bool arm_legitimate_address_p (enum machine_mode, rtx, bool);
 static int thumb_far_jump_used_p (void);
 static bool thumb_force_lr_save (void);
-static int const_ok_for_op (HOST_WIDE_INT, enum rtx_code);
 static rtx emit_sfm (int, int);
 static unsigned arm_size_return_regs (void);
 static bool arm_assemble_integer (rtx, unsigned int, int);
@@ -2375,7 +2374,7 @@ const_ok_for_arm (HOST_WIDE_INT i)
 }
 
 /* Return true if I is a valid constant for the operation CODE.  */
-static int
+int
 const_ok_for_op (HOST_WIDE_INT i, enum rtx_code code)
 {
   if (const_ok_for_arm (i))
@@ -2392,6 +2391,13 @@ const_ok_for_op (HOST_WIDE_INT i, enum rtx_code code)
 	return const_ok_for_arm (ARM_SIGN_EXTEND (~i));
 
     case PLUS:
+      /* See if we can use addw or subw.  */
+      if (TARGET_THUMB2
+	  && ((i & 0xfffff000) == 0
+	      || ((-i) & 0xfffff000) == 0))
+	return 1;
+      /* else fall through.  */
+
     case COMPARE:
     case EQ:
     case NE:
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -708,21 +708,24 @@
 ;;  (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")
-	(plus:SI (match_operand:SI 1 "s_register_operand" "%rk,k,r,rk,k,rk")
-		 (match_operand:SI 2 "reg_or_int_operand" "rI,rI,k,L, L,?n")))]
+  [(set (match_operand:SI          0 "s_register_operand" "=r, k,r,r, k, r, k,r, k, r")
+	(plus:SI (match_operand:SI 1 "s_register_operand" "%rk,k,r,rk,k, rk,k,rk,k, rk")
+		 (match_operand:SI 2 "reg_or_int_operand" "rI,rI,k,Pj,Pj,L, L,PJ,PJ,?n")))]
   "TARGET_32BIT"
   "@
    add%?\\t%0, %1, %2
    add%?\\t%0, %1, %2
    add%?\\t%0, %2, %1
+   addw%?\\t%0, %1, %2
+   addw%?\\t%0, %1, %2
    sub%?\\t%0, %1, #%n2
    sub%?\\t%0, %1, #%n2
+   subw%?\\t%0, %1, #%n2
+   subw%?\\t%0, %1, #%n2
    #"
   "TARGET_32BIT
    && GET_CODE (operands[2]) == CONST_INT
-   && !(const_ok_for_arm (INTVAL (operands[2]))
-        || const_ok_for_arm (-INTVAL (operands[2])))
+   && !const_ok_for_op (INTVAL (operands[2]), PLUS)
    && (reload_completed || !arm_eliminable_register (operands[1]))"
   [(clobber (const_int 0))]
   "
@@ -731,8 +734,9 @@
 		      operands[1], 0);
   DONE;
   "
-  [(set_attr "length" "4,4,4,4,4,16")
-   (set_attr "predicable" "yes")]
+  [(set_attr "length" "4,4,4,4,4,4,4,4,4,16")
+   (set_attr "predicable" "yes")
+   (set_attr "arch" "*,*,*,t2,t2,*,*,t2,t2,*")]
 )
 
 (define_insn_and_split "*thumb1_addsi3"
--- a/gcc/config/arm/constraints.md
+++ b/gcc/config/arm/constraints.md
@@ -31,7 +31,7 @@
 ;; The following multi-letter normal constraints have been used:
 ;; in ARM/Thumb-2 state: Da, Db, Dc, Dn, Dl, DL, Dv, Dy, Di, Dz
 ;; in Thumb-1 state: Pa, Pb, Pc, Pd
-;; in Thumb-2 state: Ps, Pt, Pu, Pv, Pw, Px, Py
+;; in Thumb-2 state: Pj, PJ, Ps, Pt, Pu, Pv, Pw, Px, Py
 
 ;; The following memory constraints have been used:
 ;; in ARM/Thumb-2 state: Q, Ut, Uv, Uy, Un, Um, Us
@@ -75,6 +75,18 @@
 	   (and (match_code "const_int")
                 (match_test "(ival & 0xffff0000) == 0")))))
 
+(define_constraint "Pj"
+ "@internal A 12-bit constant suitable for an ADDW or SUBW instruction. (Thumb-2)"
+ (and (match_code "const_int")
+      (and (match_test "TARGET_THUMB2")
+	   (match_test "(ival & 0xfffff000) == 0"))))
+
+(define_constraint "PJ"
+ "@internal A constant that satisfies the Pj constrant if negated."
+ (and (match_code "const_int")
+      (and (match_test "TARGET_THUMB2")
+	   (match_test "((-ival) & 0xfffff000) == 0"))))
+
 (define_register_constraint "k" "STACK_REG"
  "@internal The stack register.")