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-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp42
-rw-r--r--llvm/lib/Transforms/Utils/Local.cpp52
2 files changed, 76 insertions, 18 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 22832aadf4a..e70171ce989 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1620,6 +1620,30 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
/// Given an OR instruction, check to see if this is a bswap idiom. If so,
/// insert the new intrinsic and return it.
Instruction *InstCombiner::MatchBSwap(BinaryOperator &I) {
+ Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+ // Look through zero extends.
+ if (Instruction *Ext = dyn_cast<ZExtInst>(Op0))
+ Op0 = Ext->getOperand(0);
+
+ if (Instruction *Ext = dyn_cast<ZExtInst>(Op1))
+ Op1 = Ext->getOperand(0);
+
+ // (A | B) | C and A | (B | C) -> bswap if possible.
+ bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
+ match(Op1, m_Or(m_Value(), m_Value()));
+
+ // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
+ bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
+ match(Op1, m_LogicalShift(m_Value(), m_Value()));
+
+ // (A & B) | (C & D) -> bswap if possible.
+ bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
+ match(Op1, m_And(m_Value(), m_Value()));
+
+ if (!OrOfOrs && !OrOfShifts && !OrOfAnds)
+ return nullptr;
+
SmallVector<Instruction*, 4> Insts;
if (!recognizeBSwapOrBitReverseIdiom(&I, true, false, Insts))
return nullptr;
@@ -2162,23 +2186,13 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
return NV;
}
+ // Given an OR instruction, check to see if this is a bswap.
+ if (Instruction *BSwap = MatchBSwap(I))
+ return BSwap;
+
Value *A = nullptr, *B = nullptr;
ConstantInt *C1 = nullptr, *C2 = nullptr;
- // (A | B) | C and A | (B | C) -> bswap if possible.
- bool OrOfOrs = match(Op0, m_Or(m_Value(), m_Value())) ||
- match(Op1, m_Or(m_Value(), m_Value()));
- // (A >> B) | (C << D) and (A << B) | (B >> C) -> bswap if possible.
- bool OrOfShifts = match(Op0, m_LogicalShift(m_Value(), m_Value())) &&
- match(Op1, m_LogicalShift(m_Value(), m_Value()));
- // (A & B) | (C & D) -> bswap if possible.
- bool OrOfAnds = match(Op0, m_And(m_Value(), m_Value())) &&
- match(Op1, m_And(m_Value(), m_Value()));
-
- if (OrOfOrs || OrOfShifts || OrOfAnds)
- if (Instruction *BSwap = MatchBSwap(I))
- return BSwap;
-
// (X^C)|Y -> (X|Y)^C iff Y&C == 0
if (Op0->hasOneUse() &&
match(Op0, m_Xor(m_Value(A), m_ConstantInt(C1))) &&
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index a536ddc0c2b..edde166b1ed 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1773,7 +1773,23 @@ collectBitParts(Value *V, bool MatchBSwaps, bool MatchBitReversals,
// If the AndMask is zero for this bit, clear the bit.
if ((AndMask & Bit) == 0)
Result->Provenance[i] = BitPart::Unset;
+ return Result;
+ }
+
+ // If this is a zext instruction zero extend the result.
+ if (I->getOpcode() == Instruction::ZExt) {
+ auto &Res = collectBitParts(I->getOperand(0), MatchBSwaps,
+ MatchBitReversals, BPS);
+ if (!Res)
+ return Result;
+ Result = BitPart(Res->Provider, BitWidth);
+ auto NarrowBitWidth =
+ cast<IntegerType>(cast<ZExtInst>(I)->getSrcTy())->getBitWidth();
+ for (unsigned i = 0; i < NarrowBitWidth; ++i)
+ Result->Provenance[i] = Res->Provenance[i];
+ for (unsigned i = NarrowBitWidth; i < BitWidth; ++i)
+ Result->Provenance[i] = BitPart::Unset;
return Result;
}
}
@@ -1816,6 +1832,15 @@ bool llvm::recognizeBSwapOrBitReverseIdiom(
return false; // Can't do vectors or integers > 128 bits.
unsigned BW = ITy->getBitWidth();
+ unsigned DemandedBW = BW;
+ IntegerType *DemandedTy = ITy;
+ if (I->hasOneUse()) {
+ if (TruncInst *Trunc = dyn_cast<TruncInst>(I->user_back())) {
+ DemandedTy = cast<IntegerType>(Trunc->getType());
+ DemandedBW = DemandedTy->getBitWidth();
+ }
+ }
+
// Try to find all the pieces corresponding to the bswap.
std::map<Value *, Optional<BitPart>> BPS;
auto Res = collectBitParts(I, MatchBSwaps, MatchBitReversals, BPS);
@@ -1825,11 +1850,12 @@ bool llvm::recognizeBSwapOrBitReverseIdiom(
// Now, is the bit permutation correct for a bswap or a bitreverse? We can
// only byteswap values with an even number of bytes.
- bool OKForBSwap = BW % 16 == 0, OKForBitReverse = true;
- for (unsigned i = 0; i < BW; ++i) {
- OKForBSwap &= bitTransformIsCorrectForBSwap(BitProvenance[i], i, BW);
+ bool OKForBSwap = DemandedBW % 16 == 0, OKForBitReverse = true;
+ for (unsigned i = 0; i < DemandedBW; ++i) {
+ OKForBSwap &=
+ bitTransformIsCorrectForBSwap(BitProvenance[i], i, DemandedBW);
OKForBitReverse &=
- bitTransformIsCorrectForBitReverse(BitProvenance[i], i, BW);
+ bitTransformIsCorrectForBitReverse(BitProvenance[i], i, DemandedBW);
}
Intrinsic::ID Intrin;
@@ -1840,6 +1866,24 @@ bool llvm::recognizeBSwapOrBitReverseIdiom(
else
return false;
+ if (ITy != DemandedTy) {
+ Function *F = Intrinsic::getDeclaration(I->getModule(), Intrin, DemandedTy);
+ Value *Provider = Res->Provider;
+ IntegerType *ProviderTy = cast<IntegerType>(Provider->getType());
+ // We may need to truncate the provider.
+ if (DemandedTy != ProviderTy) {
+ auto *Trunc = CastInst::Create(Instruction::Trunc, Provider, DemandedTy,
+ "trunc", I);
+ InsertedInsts.push_back(Trunc);
+ Provider = Trunc;
+ }
+ auto *CI = CallInst::Create(F, Provider, "rev", I);
+ InsertedInsts.push_back(CI);
+ auto *ExtInst = CastInst::Create(Instruction::ZExt, CI, ITy, "zext", I);
+ InsertedInsts.push_back(ExtInst);
+ return true;
+ }
+
Function *F = Intrinsic::getDeclaration(I->getModule(), Intrin, ITy);
InsertedInsts.push_back(CallInst::Create(F, Res->Provider, "rev", I));
return true;
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