https://gcc.gnu.org/g:b7fe719e449db56d665da17ca4f4ba7977da34ed

commit r16-1823-gb7fe719e449db56d665da17ca4f4ba7977da34ed
Author: Pan Li <pan2...@intel.com>
Date:   Fri Jun 27 09:02:03 2025 +0800

    RISC-V: Combine vec_duplicate + vssubu.vv to vssubu.vx on GR2VR cost
    
    This patch would like to combine the vec_duplicate + vssubu.vv to the
    vssubu.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.
    
      #define DEF_VX_BINARY(T, FUNC)                                      \
      void                                                                \
      test_vx_binary (T * restrict out, T * restrict in, T x, unsigned n) \
      {                                                                   \
        for (unsigned i = 0; i < n; i++)                                  \
          out[i] = FUNC (in[i], x);                                       \
      }
    
      T sat_sub(T a, T b)
      {
        return (a - b) & (-(T)(a >= b));
      }
    
      DEF_VX_BINARY(uint32_t, sat_sub)
    
    Before this patch:
      10   │ test_vx_binary_or_int32_t_case_0:
      11   │     beq a3,zero,.L8
      12   │     vsetvli a5,zero,e32,m1,ta,ma
      13   │     vmv.v.x v2,a2
      14   │     slli    a3,a3,32
      15   │     srli    a3,a3,32
      16   │ .L3:
      17   │     vsetvli a5,a3,e32,m1,ta,ma
      18   │     vle32.v v1,0(a1)
      19   │     slli    a4,a5,2
      20   │     sub a3,a3,a5
      21   │     add a1,a1,a4
      22   │     vssubu.vv v1,v1,v2
      23   │     vse32.v v1,0(a0)
      24   │     add a0,a0,a4
      25   │     bne a3,zero,.L3
    
    After this patch:
      10   │ test_vx_binary_or_int32_t_case_0:
      11   │     beq a3,zero,.L8
      12   │     slli    a3,a3,32
      13   │     srli    a3,a3,32
      14   │ .L3:
      15   │     vsetvli a5,a3,e32,m1,ta,ma
      16   │     vle32.v v1,0(a1)
      17   │     slli    a4,a5,2
      18   │     sub a3,a3,a5
      19   │     add a1,a1,a4
      20   │     vssubu.vx v1,v1,a2
      21   │     vse32.v v1,0(a0)
      22   │     add a0,a0,a4
      23   │     bne a3,zero,.L3
    
    gcc/ChangeLog:
    
            * config/riscv/riscv-v.cc (expand_vx_binary_vec_vec_dup): Add
            new case US_MINUS.
            * config/riscv/riscv.cc (riscv_rtx_costs): Ditto.
            * config/riscv/vector-iterators.md: Add new op us_minus.
    
    Signed-off-by: Pan Li <pan2...@intel.com>

Diff:
---
 gcc/config/riscv/riscv-v.cc          | 1 +
 gcc/config/riscv/riscv.cc            | 1 +
 gcc/config/riscv/vector-iterators.md | 2 +-
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index a3d704e81cc4..69f2a1ece534 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -5583,6 +5583,7 @@ expand_vx_binary_vec_vec_dup (rtx op_0, rtx op_1, rtx 
op_2,
     case SMIN:
     case UMIN:
     case US_PLUS:
+    case US_MINUS:
       icode = code_for_pred_scalar (code, mode);
       break;
     default:
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index bbc7547d385f..f5d2b2e74aed 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -3996,6 +3996,7 @@ riscv_rtx_costs (rtx x, machine_mode mode, int 
outer_code, int opno ATTRIBUTE_UN
                    case MOD:
                    case UMOD:
                    case US_PLUS:
+                   case US_MINUS:
                      *total = get_vector_binary_rtx_cost (op, scalar2vr_cost);
                      break;
                    default:
diff --git a/gcc/config/riscv/vector-iterators.md 
b/gcc/config/riscv/vector-iterators.md
index 0e1318d1447c..782544423c41 100644
--- a/gcc/config/riscv/vector-iterators.md
+++ b/gcc/config/riscv/vector-iterators.md
@@ -4042,7 +4042,7 @@
 ])
 
 (define_code_iterator any_int_binop_no_shift_v_vdup [
-  plus minus and ior xor mult div udiv mod umod smax umax smin umin us_plus
+  plus minus and ior xor mult div udiv mod umod smax umax smin umin us_plus 
us_minus
 ])
 
 (define_code_iterator any_int_binop_no_shift_vdup_v [

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