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[RISCV] Use legally typed splat during vmv_v_v splat(x) -> vmv_v_x #173154

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Merged
XChy merged 2 commits into from
Dec 21, 2025
+24 −1
Merged

[RISCV] Use legally typed splat during vmv_v_v splat(x) -> vmv_v_x #173154

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[RISCV] Use legally typed splat during vmv_v_v splat(x) -> vmv_v_x
XChy Dec 20, 2025
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XChy Dec 21, 2025
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2 changes: 1 addition & 1 deletion llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -21974,7 +21974,7 @@ SDValue RISCVTargetLowering::PerformDAGCombine(SDNode *N,
if (sd_match(Src, m_InsertSubvector(m_Undef(), m_Value(SubVec), m_Zero())))
Src = SubVec;

SDValue SplatVal = DAG.getSplatValue(Src);
SDValue SplatVal = DAG.getSplatValue(Src, /*LegalTypes=*/true);
if (!SplatVal)
break;
MVT VT = N->getSimpleValueType(0);
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23 changes: 23 additions & 0 deletions llvm/test/CodeGen/RISCV/rvv/rvv-vmerge-to-vmv.ll
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Expand Up @@ -99,3 +99,26 @@ define <vscale x 2 x i32> @preserve_false_avl_known_le(ptr %p, <vscale x 2 x i32
%res = call <vscale x 2 x i32> @llvm.riscv.vmerge(<vscale x 2 x i32> %pt, <vscale x 2 x i32> %false, <vscale x 2 x i32> %true, <vscale x 2 x i1> %mask, i64 1)
ret <vscale x 2 x i32> %res
}

define <4 x i16> @pr173141(i1 %0, <2 x i16> %conv33) {
; CHECK-LABEL: pr173141:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: vsetivli zero, 1, e16, mf4, ta, ma
; CHECK-NEXT: vslidedown.vi v8, v8, 1
; CHECK-NEXT: vmv.x.s a0, v8
; CHECK-NEXT: vsetivli zero, 4, e16, mf2, ta, ma
; CHECK-NEXT: vmv.v.x v8, a0
; CHECK-NEXT: ret
entry:
%1 = tail call i32 @llvm.riscv.orc.b.i32(i32 1)
%sub.i = add i32 %1, 1
%2 = and i32 %sub.i, 1
%and.i = zext i32 %2 to i64
%3 = select i1 %0, i64 0, i64 %and.i
%tobool.not128 = icmp sgt i64 %3, -1
%4 = insertelement <4 x i1> zeroinitializer, i1 %tobool.not128, i64 0
%5 = shufflevector <4 x i1> %4, <4 x i1> zeroinitializer, <4 x i32> zeroinitializer
%6 = shufflevector <2 x i16> %conv33, <2 x i16> zeroinitializer, <4 x i32> <i32 1, i32 1, i32 1, i32 1>
%7 = select <4 x i1> %5, <4 x i16> %6, <4 x i16> zeroinitializer
ret <4 x i16> %7
}