[PATCH] D102687: [RISCV] Ensure shuffle splat operands are type-legal

[Fraser Cormack via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG26bd2250c187: [RISCV] Ensure shuffle splat operands are type-legal (authored by frasercrmck).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102687/new/

https://reviews.llvm.org/D102687

Files:
  llvm/include/llvm/CodeGen/SelectionDAG.h
  llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll


Index: llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
===================================================================
--- llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
+++ llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-shuffles.ll
@@ -347,3 +347,29 @@
   %s = shufflevector <8 x i64> %x, <8 x i64> <i64 5, i64 5, i64 5, i64 5, i64 5, i64 5, i64 5, i64 5>, <8 x i32> <i32 0, i32 3, i32 10, i32 9, i32 4, i32 1, i32 7, i32 14>
   ret <8 x i64> %s
 }
+
+define <4 x i8> @interleave_shuffles(<4 x i8> %x) {
+; CHECK-LABEL: interleave_shuffles:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    vsetvli zero, zero, e8,mf4,ta,mu
+; CHECK-NEXT:    vmv.x.s a0, v8
+; CHECK-NEXT:    vsetivli a1, 4, e8,mf4,ta,mu
+; CHECK-NEXT:    vrgather.vi v25, v8, 1
+; CHECK-NEXT:    addi a1, zero, 1
+; CHECK-NEXT:    vmv.s.x v26, a1
+; CHECK-NEXT:    vmv.v.i v27, 0
+; CHECK-NEXT:    vsetivli a1, 4, e8,mf4,tu,mu
+; CHECK-NEXT:    vslideup.vi v27, v26, 3
+; CHECK-NEXT:    addi a1, zero, 10
+; CHECK-NEXT:    vsetivli a2, 1, e8,mf8,ta,mu
+; CHECK-NEXT:    vmv.s.x v0, a1
+; CHECK-NEXT:    vsetivli a1, 4, e8,mf4,ta,mu
+; CHECK-NEXT:    vmv.v.x v8, a0
+; CHECK-NEXT:    vsetivli a0, 4, e8,mf4,tu,mu
+; CHECK-NEXT:    vrgather.vv v8, v25, v27, v0.t
+; CHECK-NEXT:    ret
+  %y = shufflevector <4 x i8> %x, <4 x i8> undef, <4 x i32> <i32 0, i32 0, i32 0, i32 0>
+  %z = shufflevector <4 x i8> %x, <4 x i8> undef, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
+  %w = shufflevector <4 x i8> %y, <4 x i8> %z, <4 x i32> <i32 0, i32 4, i32 1, i32 5>
+  ret <4 x i8> %w
+}
Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1849,7 +1849,7 @@
   SDValue Gather;
   // TODO: This doesn't trigger for i64 vectors on RV32, since there we
   // encounter a bitcasted BUILD_VECTOR with low/high i32 values.
-  if (SDValue SplatValue = DAG.getSplatValue(V1)) {
+  if (SDValue SplatValue = DAG.getSplatValue(V1, /*LegalTypes*/ true)) {
     Gather = lowerScalarSplat(SplatValue, VL, ContainerVT, DL, DAG, Subtarget);
   } else {
     SDValue LHSIndices = DAG.getBuildVector(IndexVT, DL, GatherIndicesLHS);
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2636,12 +2636,21 @@
   return SDValue();
 }
 
-SDValue SelectionDAG::getSplatValue(SDValue V) {
+SDValue SelectionDAG::getSplatValue(SDValue V, bool LegalTypes) {
   int SplatIdx;
-  if (SDValue SrcVector = getSplatSourceVector(V, SplatIdx))
-    return getNode(ISD::EXTRACT_VECTOR_ELT, SDLoc(V),
-                   SrcVector.getValueType().getScalarType(), SrcVector,
+  if (SDValue SrcVector = getSplatSourceVector(V, SplatIdx)) {
+    EVT SVT = SrcVector.getValueType().getScalarType();
+    EVT LegalSVT = SVT;
+    if (LegalTypes && !TLI->isTypeLegal(SVT)) {
+      if (!SVT.isInteger())
+        return SDValue();
+      LegalSVT = TLI->getTypeToTransformTo(*getContext(), LegalSVT);
+      if (LegalSVT.bitsLT(SVT))
+        return SDValue();
+    }
+    return getNode(ISD::EXTRACT_VECTOR_ELT, SDLoc(V), LegalSVT, SrcVector,
                    getVectorIdxConstant(SplatIdx, SDLoc(V)));
+  }
   return SDValue();
 }
 
Index: llvm/include/llvm/CodeGen/SelectionDAG.h
===================================================================
--- llvm/include/llvm/CodeGen/SelectionDAG.h
+++ llvm/include/llvm/CodeGen/SelectionDAG.h
@@ -1817,8 +1817,10 @@
   SDValue getSplatSourceVector(SDValue V, int &SplatIndex);
 
   /// If V is a splat vector, return its scalar source operand by extracting
-  /// that element from the source vector.
-  SDValue getSplatValue(SDValue V);
+  /// that element from the source vector. If LegalTypes is true, this method
+  /// may only return a legally-typed splat value. If it cannot legalize the
+  /// splatted value it will return SDValue().
+  SDValue getSplatValue(SDValue V, bool LegalTypes = false);
 
   /// If a SHL/SRA/SRL node \p V has a constant or splat constant shift amount
   /// that is less than the element bit-width of the shift node, return it.


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