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APInt'fy SimplifyDemandedVectorElts so it can analyze vectors with more than 64 elements.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63631 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-02-03 10:05:09 +00:00
parent 6038840210
commit 388df627cc
2 changed files with 73 additions and 49 deletions
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103
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -352,8 +352,8 @@ namespace {
/// properties that allow us to simplify its operands.
bool SimplifyDemandedInstructionBits(Instruction &Inst);
Value *SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
uint64_t &UndefElts, unsigned Depth = 0);
Value *SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
APInt& UndefElts, unsigned Depth = 0);
// FoldOpIntoPhi - Given a binary operator or cast instruction which has a
// PHI node as operand #0, see if we can fold the instruction into the PHI
@ -1396,19 +1396,18 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
/// SimplifyDemandedVectorElts - The specified value produces a vector with
/// 64 or fewer elements. DemandedElts contains the set of elements that are
/// any number of elements. DemandedElts contains the set of elements that are
/// actually used by the caller. This method analyzes which elements of the
/// operand are undef and returns that information in UndefElts.
///
/// If the information about demanded elements can be used to simplify the
/// operation, the operation is simplified, then the resultant value is
/// returned. This returns null if no change was made.
Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
uint64_t &UndefElts,
Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, APInt DemandedElts,
APInt& UndefElts,
unsigned Depth) {
unsigned VWidth = cast<VectorType>(V->getType())->getNumElements();
assert(VWidth <= 64 && "Vector too wide to analyze!");
uint64_t EltMask = ~0ULL >> (64-VWidth);
APInt EltMask(APInt::getAllOnesValue(VWidth));
assert((DemandedElts & ~EltMask) == 0 && "Invalid DemandedElts!");
if (isa<UndefValue>(V)) {
@ -1427,12 +1426,12 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
std::vector<Constant*> Elts;
for (unsigned i = 0; i != VWidth; ++i)
if (!(DemandedElts & (1ULL << i))) { // If not demanded, set to undef.
if (!DemandedElts[i]) { // If not demanded, set to undef.
Elts.push_back(Undef);
UndefElts |= (1ULL << i);
UndefElts.set(i);
} else if (isa<UndefValue>(CP->getOperand(i))) { // Already undef.
Elts.push_back(Undef);
UndefElts |= (1ULL << i);
UndefElts.set(i);
} else { // Otherwise, defined.
Elts.push_back(CP->getOperand(i));
}
@ -1453,8 +1452,10 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
Constant *Zero = Constant::getNullValue(EltTy);
Constant *Undef = UndefValue::get(EltTy);
std::vector<Constant*> Elts;
for (unsigned i = 0; i != VWidth; ++i)
Elts.push_back((DemandedElts & (1ULL << i)) ? Zero : Undef);
for (unsigned i = 0; i != VWidth; ++i) {
Constant *Elt = DemandedElts[i] ? Zero : Undef;
Elts.push_back(Elt);
}
UndefElts = DemandedElts ^ EltMask;
return ConstantVector::get(Elts);
}
@ -1482,7 +1483,7 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
if (!I) return false; // Only analyze instructions.
bool MadeChange = false;
uint64_t UndefElts2;
APInt UndefElts2(VWidth, 0);
Value *TmpV;
switch (I->getOpcode()) {
default: break;
@ -1503,35 +1504,36 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// If this is inserting an element that isn't demanded, remove this
// insertelement.
unsigned IdxNo = Idx->getZExtValue();
if (IdxNo >= VWidth || (DemandedElts & (1ULL << IdxNo)) == 0)
if (IdxNo >= VWidth || !DemandedElts[IdxNo])
return AddSoonDeadInstToWorklist(*I, 0);
// Otherwise, the element inserted overwrites whatever was there, so the
// input demanded set is simpler than the output set.
TmpV = SimplifyDemandedVectorElts(I->getOperand(0),
DemandedElts & ~(1ULL << IdxNo),
APInt DemandedElts2 = DemandedElts;
DemandedElts2.clear(IdxNo);
TmpV = SimplifyDemandedVectorElts(I->getOperand(0), DemandedElts2,
UndefElts, Depth+1);
if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
// The inserted element is defined.
UndefElts &= ~(1ULL << IdxNo);
UndefElts.clear(IdxNo);
break;
}
case Instruction::ShuffleVector: {
ShuffleVectorInst *Shuffle = cast<ShuffleVectorInst>(I);
uint64_t LHSVWidth =
cast<VectorType>(Shuffle->getOperand(0)->getType())->getNumElements();
uint64_t LeftDemanded = 0, RightDemanded = 0;
APInt LeftDemanded(LHSVWidth, 0), RightDemanded(LHSVWidth, 0);
for (unsigned i = 0; i < VWidth; i++) {
if (DemandedElts & (1ULL << i)) {
if (DemandedElts[i]) {
unsigned MaskVal = Shuffle->getMaskValue(i);
if (MaskVal != -1u) {
assert(MaskVal < LHSVWidth * 2 &&
"shufflevector mask index out of range!");
if (MaskVal < LHSVWidth)
LeftDemanded |= 1ULL << MaskVal;
LeftDemanded.set(MaskVal);
else
RightDemanded |= 1ULL << (MaskVal - LHSVWidth);
RightDemanded.set(MaskVal - LHSVWidth);
}
}
}
@ -1540,7 +1542,7 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
UndefElts2, Depth+1);
if (TmpV) { I->setOperand(0, TmpV); MadeChange = true; }
uint64_t UndefElts3;
APInt UndefElts3(VWidth, 0);
TmpV = SimplifyDemandedVectorElts(I->getOperand(1), RightDemanded,
UndefElts3, Depth+1);
if (TmpV) { I->setOperand(1, TmpV); MadeChange = true; }
@ -1549,16 +1551,17 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
for (unsigned i = 0; i < VWidth; i++) {
unsigned MaskVal = Shuffle->getMaskValue(i);
if (MaskVal == -1u) {
uint64_t NewBit = 1ULL << i;
UndefElts |= NewBit;
UndefElts.set(i);
} else if (MaskVal < LHSVWidth) {
uint64_t NewBit = ((UndefElts2 >> MaskVal) & 1) << i;
NewUndefElts |= NewBit;
UndefElts |= NewBit;
if (UndefElts2[MaskVal]) {
NewUndefElts = true;
UndefElts.set(i);
}
} else {
uint64_t NewBit = ((UndefElts3 >> (MaskVal - LHSVWidth)) & 1) << i;
NewUndefElts |= NewBit;
UndefElts |= NewBit;
if (UndefElts3[MaskVal - LHSVWidth]) {
NewUndefElts = true;
UndefElts.set(i);
}
}
}
@ -1566,7 +1569,7 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// Add additional discovered undefs.
std::vector<Constant*> Elts;
for (unsigned i = 0; i < VWidth; ++i) {
if (UndefElts & (1ULL << i))
if (UndefElts[i])
Elts.push_back(UndefValue::get(Type::Int32Ty));
else
Elts.push_back(ConstantInt::get(Type::Int32Ty,
@ -1582,7 +1585,7 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
const VectorType *VTy = dyn_cast<VectorType>(I->getOperand(0)->getType());
if (!VTy) break;
unsigned InVWidth = VTy->getNumElements();
uint64_t InputDemandedElts = 0;
APInt InputDemandedElts(InVWidth, 0);
unsigned Ratio;
if (VWidth == InVWidth) {
@ -1599,8 +1602,8 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// elements are live.
Ratio = VWidth/InVWidth;
for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx) {
if (DemandedElts & (1ULL << OutIdx))
InputDemandedElts |= 1ULL << (OutIdx/Ratio);
if (DemandedElts[OutIdx])
InputDemandedElts.set(OutIdx/Ratio);
}
} else {
// Untested so far.
@ -1611,8 +1614,8 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// live.
Ratio = InVWidth/VWidth;
for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx)
if (DemandedElts & (1ULL << InIdx/Ratio))
InputDemandedElts |= 1ULL << InIdx;
if (DemandedElts[InIdx/Ratio])
InputDemandedElts.set(InIdx);
}
// div/rem demand all inputs, because they don't want divide by zero.
@ -1630,8 +1633,8 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// then an output element is undef if the corresponding input element is
// undef.
for (unsigned OutIdx = 0; OutIdx != VWidth; ++OutIdx)
if (UndefElts2 & (1ULL << (OutIdx/Ratio)))
UndefElts |= 1ULL << OutIdx;
if (UndefElts2[OutIdx/Ratio])
UndefElts.set(OutIdx);
} else if (VWidth < InVWidth) {
assert(0 && "Unimp");
// If there are more elements in the source than there are in the result,
@ -1639,8 +1642,8 @@ Value *InstCombiner::SimplifyDemandedVectorElts(Value *V, uint64_t DemandedElts,
// elements are undef.
UndefElts = ~0ULL >> (64-VWidth); // Start out all undef.
for (unsigned InIdx = 0; InIdx != InVWidth; ++InIdx)
if ((UndefElts2 & (1ULL << InIdx)) == 0) // Not undef?
UndefElts &= ~(1ULL << (InIdx/Ratio)); // Clear undef bit.
if (!UndefElts2[InIdx]) // Not undef?
UndefElts.clear(InIdx/Ratio); // Clear undef bit.
}
break;
}
@ -9493,8 +9496,11 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
case Intrinsic::x86_sse_cvttss2si: {
// These intrinsics only demands the 0th element of its input vector. If
// we can simplify the input based on that, do so now.
uint64_t UndefElts;
if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), 1,
unsigned VWidth =
cast<VectorType>(II->getOperand(1)->getType())->getNumElements();
APInt DemandedElts(VWidth, 1);
APInt UndefElts(VWidth, 0);
if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), DemandedElts,
UndefElts)) {
II->setOperand(1, V);
return II;
@ -11868,10 +11874,10 @@ Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
// If the input vector has a single use, simplify it based on this use
// property.
if (EI.getOperand(0)->hasOneUse() && VectorWidth != 1) {
uint64_t UndefElts;
APInt UndefElts(VectorWidth, 0);
APInt DemandedMask(VectorWidth, 1 << IndexVal);
if (Value *V = SimplifyDemandedVectorElts(EI.getOperand(0),
1 << IndexVal,
UndefElts)) {
DemandedMask, UndefElts)) {
EI.setOperand(0, V);
return &EI;
}
@ -12170,15 +12176,14 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
if (isa<UndefValue>(SVI.getOperand(2)))
return ReplaceInstUsesWith(SVI, UndefValue::get(SVI.getType()));
uint64_t UndefElts;
unsigned VWidth = cast<VectorType>(SVI.getType())->getNumElements();
if (VWidth != cast<VectorType>(LHS->getType())->getNumElements())
return 0;
uint64_t AllOnesEltMask = ~0ULL >> (64-VWidth);
if (VWidth <= 64 &&
SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
APInt UndefElts(VWidth, 0);
APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
LHS = SVI.getOperand(0);
RHS = SVI.getOperand(1);
MadeChange = true;

19
test/Transforms/InstCombine/vec_demanded_elts-2.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep extractelement
define void @get_image() nounwind {
entry:
%0 = call i32 @fgetc(i8* null) nounwind ; <i32> [#uses=1]
%1 = trunc i32 %0 to i8 ; <i8> [#uses=1]
%tmp2 = insertelement <100 x i8> zeroinitializer, i8 %1, i32 1 ; <<100 x i8>> [#uses=1]
%tmp1 = extractelement <100 x i8> %tmp2, i32 0 ; <i8> [#uses=1]
%2 = icmp eq i8 %tmp1, 80 ; <i1> [#uses=1]
br i1 %2, label %bb2, label %bb3
bb2: ; preds = %entry
br label %bb3
bb3: ; preds = %bb2, %entry
unreachable
}
declare i32 @fgetc(i8*)