[RISCV] Use X0 for VLMax for slide1up/slide1down in lowerVectorIntrinsicScalars. (#101384)

topperc · web-flow · commit 36264435071e · 2024-07-31T13:01:31.000-07:00
Previously, we created a vsetvlimax intrinsic. Using X0 simplifies the
code and enables some optimizations to kick when the exact value of
vlmax is known.
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -8857,14 +8857,7 @@ static SDValue lowerVectorIntrinsicScalars(SDValue Op, SelectionDAG &DAG,
         I32VL = DAG.getConstant(2 * AVLInt, DL, XLenVT);
       } else if (AVLInt >= 2 * MaxVLMAX) {
         // Just set vl to VLMAX in this situation
-        RISCVII::VLMUL Lmul = RISCVTargetLowering::getLMUL(I32VT);
-        SDValue LMUL = DAG.getConstant(Lmul, DL, XLenVT);
-        unsigned Sew = RISCVVType::encodeSEW(I32VT.getScalarSizeInBits());
-        SDValue SEW = DAG.getConstant(Sew, DL, XLenVT);
-        SDValue SETVLMAX = DAG.getTargetConstant(
-            Intrinsic::riscv_vsetvlimax, DL, MVT::i32);
-        I32VL = DAG.getNode(ISD::INTRINSIC_WO_CHAIN, DL, XLenVT, SETVLMAX, SEW,
-                            LMUL);
+        I32VL = DAG.getRegister(RISCV::X0, XLenVT);
       } else {
         // For AVL between (MinVLMAX, 2 * MaxVLMAX), the actual working vl
         // is related to the hardware implementation.
diff --git a/llvm/test/CodeGen/RISCV/rvv/vslide1down-constant-vl-rv32.ll b/llvm/test/CodeGen/RISCV/rvv/vslide1down-constant-vl-rv32.ll
@@ -51,7 +51,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2(<vsc
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -84,7 +84,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl3(<vsc
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl3:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -117,7 +117,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl8(<vsc
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl8:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -152,7 +152,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl9(<vsc
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl9:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -187,7 +187,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl15(<vs
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl15:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -213,14 +213,14 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl16(<vs
 ;
 ; CHECK-512-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl16:
 ; CHECK-512:       # %bb.0: # %entry
-; CHECK-512-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
 ; CHECK-512-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-512-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-512-NEXT:    ret
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl16:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -247,14 +247,14 @@ define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2047(<
 ;
 ; CHECK-512-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2047:
 ; CHECK-512:       # %bb.0: # %entry
-; CHECK-512-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
 ; CHECK-512-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-512-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-512-NEXT:    ret
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2047:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
 ; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
 ; CHECK-64-NEXT:    ret
@@ -269,12 +269,26 @@ entry:
 }
 
 define <vscale x 1 x i64> @intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2048(<vscale x 1 x i64> %0, i64 %1) nounwind {
-; CHECK-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2048:
-; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
-; CHECK-NEXT:    vslide1down.vx v8, v8, a0
-; CHECK-NEXT:    vslide1down.vx v8, v8, a1
-; CHECK-NEXT:    ret
+; CHECK-128-65536-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-128-65536:       # %bb.0: # %entry
+; CHECK-128-65536-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-128-65536-NEXT:    vslide1down.vx v8, v8, a0
+; CHECK-128-65536-NEXT:    vslide1down.vx v8, v8, a1
+; CHECK-128-65536-NEXT:    ret
+;
+; CHECK-512-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-512:       # %bb.0: # %entry
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
+; CHECK-512-NEXT:    vslide1down.vx v8, v8, a0
+; CHECK-512-NEXT:    vslide1down.vx v8, v8, a1
+; CHECK-512-NEXT:    ret
+;
+; CHECK-64-LABEL: intrinsic_vslide1down_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-64:       # %bb.0: # %entry
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
+; CHECK-64-NEXT:    vslide1down.vx v8, v8, a0
+; CHECK-64-NEXT:    vslide1down.vx v8, v8, a1
+; CHECK-64-NEXT:    ret
 entry:
   %a = call <vscale x 1 x i64> @llvm.riscv.vslide1down.nxv1i64.i64(
     <vscale x 1 x i64> undef,
diff --git a/llvm/test/CodeGen/RISCV/rvv/vslide1up-constant-vl-rv32.ll b/llvm/test/CodeGen/RISCV/rvv/vslide1up-constant-vl-rv32.ll
@@ -51,7 +51,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2(<vscal
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -84,7 +84,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl3(<vscal
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl3:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -117,7 +117,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl8(<vscal
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl8:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -152,7 +152,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl9(<vscal
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl9:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -187,7 +187,7 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl15(<vsca
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl15:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -213,14 +213,14 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl16(<vsca
 ;
 ; CHECK-512-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl16:
 ; CHECK-512:       # %bb.0: # %entry
-; CHECK-512-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
 ; CHECK-512-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-512-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-512-NEXT:    ret
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl16:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -247,14 +247,14 @@ define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2047(<vs
 ;
 ; CHECK-512-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2047:
 ; CHECK-512:       # %bb.0: # %entry
-; CHECK-512-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
 ; CHECK-512-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-512-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-512-NEXT:    ret
 ;
 ; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2047:
 ; CHECK-64:       # %bb.0: # %entry
-; CHECK-64-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
 ; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
 ; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
 ; CHECK-64-NEXT:    ret
@@ -269,12 +269,26 @@ entry:
 }
 
 define <vscale x 1 x i64> @intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2048(<vscale x 1 x i64> %0, i64 %1) nounwind {
-; CHECK-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2048:
-; CHECK:       # %bb.0: # %entry
-; CHECK-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
-; CHECK-NEXT:    vslide1up.vx v9, v8, a1
-; CHECK-NEXT:    vslide1up.vx v8, v9, a0
-; CHECK-NEXT:    ret
+; CHECK-128-65536-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-128-65536:       # %bb.0: # %entry
+; CHECK-128-65536-NEXT:    vsetvli a2, zero, e32, m1, ta, ma
+; CHECK-128-65536-NEXT:    vslide1up.vx v9, v8, a1
+; CHECK-128-65536-NEXT:    vslide1up.vx v8, v9, a0
+; CHECK-128-65536-NEXT:    ret
+;
+; CHECK-512-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-512:       # %bb.0: # %entry
+; CHECK-512-NEXT:    vsetivli zero, 16, e32, m1, ta, ma
+; CHECK-512-NEXT:    vslide1up.vx v9, v8, a1
+; CHECK-512-NEXT:    vslide1up.vx v8, v9, a0
+; CHECK-512-NEXT:    ret
+;
+; CHECK-64-LABEL: intrinsic_vslide1up_vx_nxv1i64_nxv1i64_i64_vl2048:
+; CHECK-64:       # %bb.0: # %entry
+; CHECK-64-NEXT:    vsetivli zero, 2, e32, m1, ta, ma
+; CHECK-64-NEXT:    vslide1up.vx v9, v8, a1
+; CHECK-64-NEXT:    vslide1up.vx v8, v9, a0
+; CHECK-64-NEXT:    ret
 entry:
   %a = call <vscale x 1 x i64> @llvm.riscv.vslide1up.nxv1i64.i64(
     <vscale x 1 x i64> undef,
