forked from OSchip/llvm-project
[X86] Remove zext from vXi32 to vXi64 on indices of gather/scatter instructions if we can prove the pre-extended value is positive.
Gather/scatter can implicitly sign extend from i32->i64 on indices. So if we know the sign bit of the input to a zext is 0 we can use the implicit extension. llvm-svn: 321209
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@ -36273,6 +36273,23 @@ static SDValue combineGatherScatter(SDNode *N, SelectionDAG &DAG,
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DCI.AddToWorklist(N);
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return SDValue(N, 0);
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}
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// Try to remove zero extends from 32->64 if we know the sign bit of
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// the input is zero.
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if (Index.getOpcode() == ISD::ZERO_EXTEND &&
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Index.getScalarValueSizeInBits() == 64 &&
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Index.getOperand(0).getScalarValueSizeInBits() == 32) {
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if (DAG.SignBitIsZero(Index.getOperand(0))) {
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SmallVector<SDValue, 5> NewOps(N->op_begin(), N->op_end());
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NewOps[4] = Index.getOperand(0);
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DAG.UpdateNodeOperands(N, NewOps);
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// The original zero extend has less users, add back to worklist in case
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// it needs to be removed
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DCI.AddToWorklist(Index.getNode());
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DCI.AddToWorklist(N);
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return SDValue(N, 0);
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}
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}
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}
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// Gather and Scatter instructions use k-registers for masks. The type of
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@ -2742,3 +2742,48 @@ define void @test_scatter_2i32_index(<2 x double> %a1, double* %base, <2 x i32>
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}
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declare void @llvm.masked.scatter.v2f64.v2p0f64(<2 x double>, <2 x double*>, i32, <2 x i1>)
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define <16 x float> @zext_index(float* %base, <16 x i32> %ind) {
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; KNL_64-LABEL: zext_index:
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; KNL_64: # %bb.0:
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; KNL_64-NEXT: vpandd {{.*}}(%rip){1to16}, %zmm0, %zmm1
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; KNL_64-NEXT: kxnorw %k0, %k0, %k1
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; KNL_64-NEXT: vgatherdps (%rdi,%zmm1,4), %zmm0 {%k1}
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; KNL_64-NEXT: retq
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;
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; KNL_32-LABEL: zext_index:
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; KNL_32: # %bb.0:
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; KNL_32-NEXT: movl {{[0-9]+}}(%esp), %eax
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; KNL_32-NEXT: vpandd {{\.LCPI.*}}{1to16}, %zmm0, %zmm1
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; KNL_32-NEXT: kxnorw %k0, %k0, %k1
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; KNL_32-NEXT: vgatherdps (%eax,%zmm1,4), %zmm0 {%k1}
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; KNL_32-NEXT: retl
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;
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; SKX_SMALL-LABEL: zext_index:
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; SKX_SMALL: # %bb.0:
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; SKX_SMALL-NEXT: vandps {{.*}}(%rip){1to16}, %zmm0, %zmm1
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; SKX_SMALL-NEXT: kxnorw %k0, %k0, %k1
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; SKX_SMALL-NEXT: vgatherdps (%rdi,%zmm1,4), %zmm0 {%k1}
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; SKX_SMALL-NEXT: retq
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;
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; SKX_LARGE-LABEL: zext_index:
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; SKX_LARGE: # %bb.0:
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; SKX_LARGE-NEXT: movabsq ${{\.LCPI.*}}, %rax
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; SKX_LARGE-NEXT: vandps (%rax){1to16}, %zmm0, %zmm1
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; SKX_LARGE-NEXT: kxnorw %k0, %k0, %k1
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; SKX_LARGE-NEXT: vgatherdps (%rdi,%zmm1,4), %zmm0 {%k1}
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; SKX_LARGE-NEXT: retq
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;
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; SKX_32-LABEL: zext_index:
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; SKX_32: # %bb.0:
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; SKX_32-NEXT: movl {{[0-9]+}}(%esp), %eax
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; SKX_32-NEXT: vandps {{\.LCPI.*}}{1to16}, %zmm0, %zmm1
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; SKX_32-NEXT: kxnorw %k0, %k0, %k1
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; SKX_32-NEXT: vgatherdps (%eax,%zmm1,4), %zmm0 {%k1}
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; SKX_32-NEXT: retl
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%ind_masked = and <16 x i32> %ind, <i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15, i32 15>
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%sext_ind = zext <16 x i32> %ind_masked to <16 x i64>
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%gep.random = getelementptr float, float *%base, <16 x i64> %sext_ind
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%res = call <16 x float> @llvm.masked.gather.v16f32.v16p0f32(<16 x float*> %gep.random, i32 4, <16 x i1> <i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true, i1 true>, <16 x float> undef)
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ret <16 x float>%res
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}
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