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[RISCV] Check the legality of source vector types in matchSplatAsGather (#133028)

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When we're trying to lower `extractelement + splat` with
vrgather.vi/.vx, we should also check the legality of source vector type
from `extractelement`, as the entire transformation assumes legal types.

Fixes #133020
This commit is contained in:
Min-Yih Hsu 2025-03-26 12:07:02 -07:00 committed by GitHub
parent 1876a89b25
commit 25c5bad2f2
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2 changed files with 17 additions and 1 deletions
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3
llvm/lib/Target/RISCV/RISCVISelLowering.cpp
View File

@ -3566,7 +3566,8 @@ static SDValue matchSplatAsGather(SDValue SplatVal, MVT VT, const SDLoc &DL,
// FIXME: Support i1 vectors, maybe by promoting to i8?
MVT EltTy = VT.getVectorElementType();
MVT SrcVT = Src.getSimpleValueType();
if (EltTy == MVT::i1 || EltTy != SrcVT.getVectorElementType())
if (EltTy == MVT::i1 || EltTy != SrcVT.getVectorElementType() ||
!DAG.getTargetLoweringInfo().isTypeLegal(SrcVT))
return SDValue();
SDValue Idx = SplatVal.getOperand(1);
// The index must be a legal type.

15
llvm/test/CodeGen/RISCV/rvv/splat-vectors.ll
View File

@ -230,6 +230,21 @@ define <8 x float> @splat_idx_nxv4f32_v8f32_constant_7(<vscale x 4 x float> %v)
ret <8 x float> %splat
}
; This test shouldn't crash.
define <vscale x 2 x float> @splat_idx_illegal_type(<3 x float> %v) {
; CHECK-LABEL: splat_idx_illegal_type:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: vsetvli a0, zero, e32, m1, ta, ma
; CHECK-NEXT: vrgather.vi v9, v8, 0
; CHECK-NEXT: vmv.v.v v8, v9
; CHECK-NEXT: ret
entry:
%x = extractelement <3 x float> %v, i64 0
%ins = insertelement <vscale x 2 x float> poison, float %x, i64 0
%splat = shufflevector <vscale x 2 x float> %ins, <vscale x 2 x float> poison, <vscale x 2 x i32> zeroinitializer
ret <vscale x 2 x float> %splat
}
; Negative test, vscale might be 4
define <8 x float> @splat_idx_nxv4f32_v8f32_constant_8(<vscale x 4 x float> %v) {
; CHECK-LABEL: splat_idx_nxv4f32_v8f32_constant_8: