RISC-V: Combine vec_duplicate + vnmsub.vv to vnmsub.vx on GR2VR cost

This patch would like to combine the vec_duplicate + vnmsub.vv to the
vnmsub.vx.  From example as below code.  The related pattern will depend
on the cost of vec_duplicate from GR2VR.  Then the late-combine will
take action if the cost of GR2VR is zero, and reject the combination
if the GR2VR cost is greater than zero.

Assume we have example code like below, GR2VR cost is 0.

Before this patch:
  11   │     beq a3,zero,.L8
  12   │     vsetvli a5,zero,e32,m1,ta,ma
  13   │     vmv.v.x v2,a2
  ...
  16   │ .L3:
  17   │     vsetvli a5,a3,e32,m1,ta,ma
  ...
  22   │     vnmsub.vv v1,v2,v3
  ...
  25   │     bne a3,zero,.L3

After this patch:
  11   │     beq a3,zero,.L8
  ...
  14   │ .L3:
  15   │     vsetvli a5,a3,e32,m1,ta,ma
  ...
  20   │     vnmsub.vx v1,a2,v3
  ...
  23   │     bne a3,zero,.L3

gcc/ChangeLog:

	* config/riscv/autovec-opt.md (*vnmsac_vx_<mode>): Rename from.
	(*mul_minus_vx_<mode>): Rename to and add nmsub support.
	* config/riscv/vector.md (@pred_vnmsac_vx_<mode>): Rename from.
	(@pred_mul_minus_vx_<mode>): Rename to and add nmsub support.
	(*pred_nmsac_<mode>_scalar_undef): Rename from.
	(*pred_mul_minus_vx<mode>_undef): Rename to and add nmsub support.

Signed-off-by: Pan Li <pan2.li@intel.com>

2 files changed, 31 insertions, 27 deletions

diff --git a/gcc/config/riscv/autovec-opt.md b/gcc/config/riscv/autovec-opt.md
index 331d08c..328ee0e 100644
--- a/gcc/config/riscv/autovec-opt.md
+++ b/gcc/config/riscv/autovec-opt.md
@@ -1846,10 +1846,10 @@
   }
   [(set_attr "type" "vimuladd")])
 
-(define_insn_and_split "*vnmsac_vx_<mode>"
+(define_insn_and_split "*mul_minus_vx_<mode>"
  [(set (match_operand:V_VLSI 0 "register_operand")
    (minus:V_VLSI
-    (match_operand:V_VLSI   3 "register_operand")
+    (match_operand:V_VLSI    3 "register_operand")
     (mult:V_VLSI
      (vec_duplicate:V_VLSI
       (match_operand:<VEL>   1 "register_operand"))
@@ -1859,9 +1859,9 @@
   "&& 1"
   [(const_int 0)]
   {
-    insn_code icode = code_for_pred_vnmsac_vx (<MODE>mode);
-    rtx ops[] = {operands[0], operands[1], operands[2], operands[3],
-		 RVV_VUNDEF(<MODE>mode)};
+    insn_code icode = code_for_pred_mul_minus_vx (<MODE>mode);
+    rtx v_undef = RVV_VUNDEF(<MODE>mode);
+    rtx ops[] = {operands[0], operands[1], operands[2], operands[3], v_undef};
     riscv_vector::emit_vlmax_insn (icode, riscv_vector::TERNARY_OP, ops);
 
     DONE;
diff --git a/gcc/config/riscv/vector.md b/gcc/config/riscv/vector.md
index 969510b..95d44ba 100644
--- a/gcc/config/riscv/vector.md
+++ b/gcc/config/riscv/vector.md
@@ -5493,7 +5493,7 @@
   "TARGET_VECTOR"
 {})
 
-(define_expand "@pred_vnmsac_vx_<mode>"
+(define_expand "@pred_mul_minus_vx_<mode>"
   [(set (match_operand:V_VLSI_QHS       0 "register_operand")
 	(if_then_else:V_VLSI_QHS
 	  (unspec:<VM>
@@ -5516,7 +5516,7 @@
   riscv_vector::prepare_ternary_operands (operands);
 })
 
-(define_expand "@pred_vnmsac_vx_<mode>"
+(define_expand "@pred_mul_minus_vx_<mode>"
   [(set (match_operand:V_VLSI_D       0 "register_operand")
 	(if_then_else:V_VLSI_D
 	  (unspec:<VM>
@@ -8888,52 +8888,56 @@
   [(set_attr "type" "vssegt<order>x")
    (set_attr "mode" "<V32T:MODE>")])
 
-(define_insn "*pred_nmsac_<mode>_scalar_undef"
-  [(set (match_operand:V_VLSI_QHS       0 "register_operand"      "=vd,  vr")
+(define_insn "*pred_mul_minus_vx<mode>_undef"
+  [(set (match_operand:V_VLSI_QHS       0 "register_operand"      "=vd,  vd,  vr,  vr")
 	(if_then_else:V_VLSI_QHS
 	  (unspec:<VM>
-	    [(match_operand:<VM>        1 "vector_mask_operand"   " vm, Wc1")
-	     (match_operand             6 "vector_length_operand" "rvl, rvl")
-	     (match_operand             7 "const_int_operand"     "  i,   i")
-	     (match_operand             8 "const_int_operand"     "  i,   i")
-	     (match_operand             9 "const_int_operand"     "  i,   i")
+	    [(match_operand:<VM>        1 "vector_mask_operand"   " vm,  vm, Wc1, Wc1")
+	     (match_operand             6 "vector_length_operand" "rvl, rvl, rvl, rvl")
+	     (match_operand             7 "const_int_operand"     "  i,   i,   i,   i")
+	     (match_operand             8 "const_int_operand"     "  i,   i,   i,   i")
+	     (match_operand             9 "const_int_operand"     "  i,   i,   i,   i")
 	     (reg:SI VL_REGNUM)
 	     (reg:SI VTYPE_REGNUM)] UNSPEC_VPREDICATE)
 	  (minus:V_VLSI_QHS
-	    (match_operand:V_VLSI_QHS   5 "register_operand"     "   0,   0")
+	    (match_operand:V_VLSI_QHS   5 "register_operand"     "  vr,   0,  vr,   0")
 	    (mult:V_VLSI_QHS
 	      (vec_duplicate:V_VLSI_QHS
-		(match_operand:<VEL>    3 "reg_or_0_operand"     "  rJ,  rJ"))
-	      (match_operand:V_VLSI_QHS 4 "register_operand"     "  vr,  vr")))
+		(match_operand:<VEL>    3 "reg_or_0_operand"     "  rJ,  rJ,  rJ,  rJ"))
+	      (match_operand:V_VLSI_QHS 4 "register_operand"     "   0,  vr,   0,  vr")))
 	  (match_operand:V_VLSI_QHS     2 "vector_undef_operand")))]
   "TARGET_VECTOR"
   "@
+   vnmsub.vx\t%0,%z3,%5%p1
    vnmsac.vx\t%0,%z3,%4%p1
+   vnmsub.vx\t%0,%z3,%5%p1
    vnmsac.vx\t%0,%z3,%4%p1"
   [(set_attr "type" "vimuladd")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "*pred_nmsac_<mode>_scalar_undef"
-  [(set (match_operand:V_VLSI_D       0 "register_operand"      "=vd,  vr")
+(define_insn "*pred_mul_minus_vx<mode>_undef"
+  [(set (match_operand:V_VLSI_D       0 "register_operand"      "=vd,  vd,  vr,  vr")
 	(if_then_else:V_VLSI_D
 	  (unspec:<VM>
-	    [(match_operand:<VM>      1 "vector_mask_operand"   " vm, Wc1")
-	     (match_operand           6 "vector_length_operand" "rvl, rvl")
-	     (match_operand           7 "const_int_operand"     "  i,   i")
-	     (match_operand           8 "const_int_operand"     "  i,   i")
-	     (match_operand           9 "const_int_operand"     "  i,   i")
+	    [(match_operand:<VM>      1 "vector_mask_operand"   " vm,  vm, Wc1, Wc1")
+	     (match_operand           6 "vector_length_operand" "rvl, rvl, rvl, rvl")
+	     (match_operand           7 "const_int_operand"     "  i,   i,   i,   i")
+	     (match_operand           8 "const_int_operand"     "  i,   i,   i,   i")
+	     (match_operand           9 "const_int_operand"     "  i,   i,   i,   i")
 	     (reg:SI VL_REGNUM)
 	     (reg:SI VTYPE_REGNUM)] UNSPEC_VPREDICATE)
 	  (minus:V_VLSI_D
-	    (match_operand:V_VLSI_D   5 "register_operand"     "   0,   0")
+	    (match_operand:V_VLSI_D   5 "register_operand"     "  vr,   0,  vr,   0")
 	    (mult:V_VLSI_D
 	      (vec_duplicate:V_VLSI_D
-		(match_operand:<VEL>  3 "reg_or_0_operand"     "  rJ,  rJ"))
-	      (match_operand:V_VLSI_D 4 "register_operand"     "  vr,  vr")))
+		(match_operand:<VEL>  3 "reg_or_0_operand"     "  rJ,  rJ,  rJ,  rJ"))
+	      (match_operand:V_VLSI_D 4 "register_operand"     "   0,  vr,   0,  vr")))
 	  (match_operand:V_VLSI_D     2 "vector_undef_operand")))]
   "TARGET_VECTOR && TARGET_64BIT"
   "@
+   vnmsub.vx\t%0,%z3,%5%p1
    vnmsac.vx\t%0,%z3,%4%p1
+   vnmsub.vx\t%0,%z3,%5%p1
    vnmsac.vx\t%0,%z3,%4%p1"
   [(set_attr "type" "vimuladd")
    (set_attr "mode" "<MODE>")])