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[X86] Fixes bug in build_vector v4x32 lowering

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r222375 made some improvements to build_vector lowering of v4x32 and v4xf32 into an insertps, but it missed a case where:

1. A single extracted element is used twice.
2. The lower of the two non-zero indexes should be preserved, and the higher should be used for the dest mask.

This caused a crash, since the source value for the insertps ends-up uninitialized.

Differential Revision: http://reviews.llvm.org/D6377

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222635 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Michael Kuperstein
2014-11-23 13:09:06 +00:00
parent 71777d18ad
commit d539147834
2 changed files with 23 additions and 3 deletions
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9
lib/Target/X86/X86ISelLowering.cpp
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@@ -5771,7 +5771,8 @@ static SDValue LowerBuildVectorv4x32(SDValue Op, SelectionDAG &DAG,
// We only know how to deal with build_vector nodes where elements are either
// zeroable or extract_vector_elt with constant index.
SDValue FirstNonZero;
for (int i=0; i < 4; ++i) {
unsigned FirstNonZeroIdx;
for (unsigned i=0; i < 4; ++i) {
if (Zeroable[i])
continue;
SDValue Elt = Op->getOperand(i);
@@ -5782,8 +5783,10 @@ static SDValue LowerBuildVectorv4x32(SDValue Op, SelectionDAG &DAG,
MVT VT = Elt.getOperand(0).getSimpleValueType();
if (!VT.is128BitVector())
return SDValue();
if (!FirstNonZero.getNode())
if (!FirstNonZero.getNode()) {
FirstNonZero = Elt;
FirstNonZeroIdx = i;
}
}
assert(FirstNonZero.getNode() && "Unexpected build vector of all zeros!");
@@ -5822,7 +5825,7 @@ static SDValue LowerBuildVectorv4x32(SDValue Op, SelectionDAG &DAG,
return SDValue();
SDValue V2 = Elt.getOperand(0);
if (Elt == FirstNonZero)
if (Elt == FirstNonZero && EltIdx == FirstNonZeroIdx)
V1 = SDValue();
bool CanFold = true;