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[X86] Pre-allocate SmallVector instead of using push_back in a loop. NFC 

llvm-svn: 273234
This commit is contained in:
Craig Topper 2016-06-21 03:05:40 +00:00
parent 69a00f06b0
commit e4cf09ad07
1 changed files with 13 additions and 17 deletions
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30
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -10326,21 +10326,22 @@ static SDValue lower128BitVectorShuffle(const SDLoc &DL, ArrayRef<int> Mask,
/// a zero-ed lane of a vector.
static bool canWidenShuffleElements(ArrayRef<int> Mask,
SmallVectorImpl<int> &WidenedMask) {
WidenedMask.assign(Mask.size() / 2, 0);
for (int i = 0, Size = Mask.size(); i < Size; i += 2) {
// If both elements are undef, its trivial.
if (Mask[i] == SM_SentinelUndef && Mask[i + 1] == SM_SentinelUndef) {
WidenedMask.push_back(SM_SentinelUndef);
WidenedMask[i/2] = SM_SentinelUndef;
continue;
}
// Check for an undef mask and a mask value properly aligned to fit with
// a pair of values. If we find such a case, use the non-undef mask's value.
if (Mask[i] == SM_SentinelUndef && Mask[i + 1] >= 0 && Mask[i + 1] % 2 == 1) {
WidenedMask.push_back(Mask[i + 1] / 2);
WidenedMask[i/2] = Mask[i + 1] / 2;
continue;
}
if (Mask[i + 1] == SM_SentinelUndef && Mask[i] >= 0 && Mask[i] % 2 == 0) {
WidenedMask.push_back(Mask[i] / 2);
WidenedMask[i/2] = Mask[i] / 2;
continue;
}
@ -10348,7 +10349,7 @@ static bool canWidenShuffleElements(ArrayRef<int> Mask,
if (Mask[i] == SM_SentinelZero || Mask[i + 1] == SM_SentinelZero) {
if ((Mask[i] == SM_SentinelZero || Mask[i] == SM_SentinelUndef) &&
(Mask[i + 1] == SM_SentinelZero || Mask[i + 1] == SM_SentinelUndef)) {
WidenedMask.push_back(SM_SentinelZero);
WidenedMask[i/2] = SM_SentinelZero;
continue;
}
return false;
@ -10357,7 +10358,7 @@ static bool canWidenShuffleElements(ArrayRef<int> Mask,
// Finally check if the two mask values are adjacent and aligned with
// a pair.
if (Mask[i] != SM_SentinelUndef && Mask[i] % 2 == 0 && Mask[i] + 1 == Mask[i + 1]) {
WidenedMask.push_back(Mask[i] / 2);
WidenedMask[i/2] = Mask[i] / 2;
continue;
}
@ -10431,7 +10432,9 @@ static SDValue splitAndLowerVectorShuffle(const SDLoc &DL, MVT VT, SDValue V1,
// Now create two 4-way blends of these half-width vectors.
auto HalfBlend = [&](ArrayRef<int> HalfMask) {
bool UseLoV1 = false, UseHiV1 = false, UseLoV2 = false, UseHiV2 = false;
SmallVector<int, 32> V1BlendMask, V2BlendMask, BlendMask;
SmallVector<int, 32> V1BlendMask((unsigned)SplitNumElements, -1);
SmallVector<int, 32> V2BlendMask((unsigned)SplitNumElements, -1);
SmallVector<int, 32> BlendMask((unsigned)SplitNumElements, -1);
for (int i = 0; i < SplitNumElements; ++i) {
int M = HalfMask[i];
if (M >= NumElements) {
@ -10439,21 +10442,15 @@ static SDValue splitAndLowerVectorShuffle(const SDLoc &DL, MVT VT, SDValue V1,
UseHiV2 = true;
else
UseLoV2 = true;
V2BlendMask.push_back(M - NumElements);
V1BlendMask.push_back(-1);
BlendMask.push_back(SplitNumElements + i);
V2BlendMask[i] = M - NumElements;
BlendMask[i] = SplitNumElements + i;
} else if (M >= 0) {
if (M >= SplitNumElements)
UseHiV1 = true;
else
UseLoV1 = true;
V2BlendMask.push_back(-1);
V1BlendMask.push_back(M);
BlendMask.push_back(i);
} else {
V2BlendMask.push_back(-1);
V1BlendMask.push_back(-1);
BlendMask.push_back(-1);
V1BlendMask[i] = M;
BlendMask[i] = i;
}
}
@ -24976,7 +24973,6 @@ static bool combineX86ShufflesRecursively(SDValue Op, SDValue Root,
SmallVector<int, 16> WidenedMask;
while (Mask.size() > 1 && canWidenShuffleElements(Mask, WidenedMask)) {
Mask = std::move(WidenedMask);
WidenedMask.clear();
}
return combineX86ShuffleChain(Input0, Root, Mask, Depth, HasPSHUFB, DAG, DCI,