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[X86][AVX] Don't let X86ISD::BROADCAST peek through bitcasts to illegal types. 

This was an existing bug exposed by the more aggressive X86ISD::BROADCAST generation by rG8817334ce3c7

Original test case thanks to @mstorsjo
This commit is contained in:
Simon Pilgrim 2020-05-08 12:30:33 +01:00
parent a0da4466d8
commit 5f9f37c42a
2 changed files with 28 additions and 1 deletions
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3
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -35565,7 +35565,8 @@ static SDValue combineTargetShuffle(SDValue N, SelectionDAG &DAG,
// broadcast(bitcast(src)) -> bitcast(broadcast(src))
// 32-bit targets have to bitcast i64 to f64, so better to bitcast upward.
if (Src.getOpcode() == ISD::BITCAST &&
SrcVT.getScalarSizeInBits() == BCVT.getScalarSizeInBits()) {
SrcVT.getScalarSizeInBits() == BCVT.getScalarSizeInBits() &&
DAG.getTargetLoweringInfo().isTypeLegal(BCVT)) {
EVT NewVT = EVT::getVectorVT(*DAG.getContext(), BCVT.getScalarType(),
VT.getVectorNumElements());
return DAG.getBitcast(VT, DAG.getNode(X86ISD::VBROADCAST, DL, NewVT, BC));

26
llvm/test/CodeGen/X86/vector-shuffle-combining-avx2.ll
View File

@ -778,6 +778,32 @@ define <32 x i8> @constant_fold_pshufb_256() {
ret <32 x i8> %1
}
define i32 @broadcast_v2i64_multiuse(i64* %p0) {
; X86-LABEL: broadcast_v2i64_multiuse:
; X86: # %bb.0: # %entry
; X86-NEXT: movl {{[0-9]+}}(%esp), %ecx
; X86-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
; X86-NEXT: vmovddup {{.*#+}} xmm0 = xmm0[0,0]
; X86-NEXT: vextractps $2, %xmm0, %eax
; X86-NEXT: addl (%ecx), %eax
; X86-NEXT: retl
;
; X64-LABEL: broadcast_v2i64_multiuse:
; X64: # %bb.0: # %entry
; X64-NEXT: movl (%rdi), %eax
; X64-NEXT: addl %eax, %eax
; X64-NEXT: retq
entry:
%tmp = load i64, i64* %p0, align 8
%tmp1 = trunc i64 %tmp to i32
%tmp2 = insertelement <2 x i64> undef, i64 %tmp, i32 0
%tmp3 = shufflevector <2 x i64> %tmp2, <2 x i64> undef, <2 x i32> zeroinitializer
%tmp4 = trunc <2 x i64> %tmp3 to <2 x i32>
%tmp5 = extractelement <2 x i32> %tmp4, i32 1
%tmp6 = add i32 %tmp1, %tmp5
ret i32 %tmp6
}
define <32 x i8> @PR27320(<8 x i32> %a0) {
; CHECK-LABEL: PR27320:
; CHECK: # %bb.0: