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https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-14 11:32:34 +00:00
implement some simple bswap optimizations, rdar://5992453
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52442 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
parent
a2eec61607
commit
0521e3cdc1
@ -1304,6 +1304,46 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, APInt DemandedMask,
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KnownZero = APInt::getHighBitsSet(BitWidth, Leaders) & DemandedMask;
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break;
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}
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case Instruction::Call:
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if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
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switch (II->getIntrinsicID()) {
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default: break;
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case Intrinsic::bswap: {
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// If the only bits demanded come from one byte of the bswap result,
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// just shift the input byte into position to eliminate the bswap.
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unsigned NLZ = DemandedMask.countLeadingZeros();
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unsigned NTZ = DemandedMask.countTrailingZeros();
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// Round NTZ down to the next byte. If we have 11 trailing zeros, then
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// we need all the bits down to bit 8. Likewise, round NLZ. If we
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// have 14 leading zeros, round to 8.
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NLZ &= ~7;
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NTZ &= ~7;
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// If we need exactly one byte, we can do this transformation.
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if (BitWidth-NLZ-NTZ == 8) {
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unsigned ResultBit = NTZ;
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unsigned InputBit = BitWidth-NTZ-8;
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// Replace this with either a left or right shift to get the byte into
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// the right place.
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Instruction *NewVal;
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if (InputBit > ResultBit)
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NewVal = BinaryOperator::CreateLShr(I->getOperand(1),
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ConstantInt::get(I->getType(), InputBit-ResultBit));
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else
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NewVal = BinaryOperator::CreateShl(I->getOperand(1),
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ConstantInt::get(I->getType(), ResultBit-InputBit));
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NewVal->takeName(I);
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InsertNewInstBefore(NewVal, *I);
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return UpdateValueUsesWith(I, NewVal);
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}
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// TODO: Could compute known zero/one bits based on the input.
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break;
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}
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}
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}
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break;
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}
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// If the client is only demanding bits that we know, return the known
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@ -8533,144 +8573,150 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
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}
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if (Changed) return II;
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} else {
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switch (II->getIntrinsicID()) {
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default: break;
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case Intrinsic::ppc_altivec_lvx:
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case Intrinsic::ppc_altivec_lvxl:
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case Intrinsic::x86_sse_loadu_ps:
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case Intrinsic::x86_sse2_loadu_pd:
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case Intrinsic::x86_sse2_loadu_dq:
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// Turn PPC lvx -> load if the pointer is known aligned.
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// Turn X86 loadups -> load if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
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Value *Ptr = InsertBitCastBefore(II->getOperand(1),
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PointerType::getUnqual(II->getType()),
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CI);
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return new LoadInst(Ptr);
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}
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break;
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case Intrinsic::ppc_altivec_stvx:
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case Intrinsic::ppc_altivec_stvxl:
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// Turn stvx -> store if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(2), 16) >= 16) {
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const Type *OpPtrTy =
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PointerType::getUnqual(II->getOperand(1)->getType());
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Value *Ptr = InsertBitCastBefore(II->getOperand(2), OpPtrTy, CI);
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return new StoreInst(II->getOperand(1), Ptr);
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}
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break;
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case Intrinsic::x86_sse_storeu_ps:
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case Intrinsic::x86_sse2_storeu_pd:
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case Intrinsic::x86_sse2_storeu_dq:
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case Intrinsic::x86_sse2_storel_dq:
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// Turn X86 storeu -> store if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
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const Type *OpPtrTy =
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PointerType::getUnqual(II->getOperand(2)->getType());
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Value *Ptr = InsertBitCastBefore(II->getOperand(1), OpPtrTy, CI);
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return new StoreInst(II->getOperand(2), Ptr);
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}
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break;
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case Intrinsic::x86_sse_cvttss2si: {
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// These intrinsics only demands the 0th element of its input vector. If
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// we can simplify the input based on that, do so now.
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uint64_t UndefElts;
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if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), 1,
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UndefElts)) {
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II->setOperand(1, V);
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return II;
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}
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break;
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}
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switch (II->getIntrinsicID()) {
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default: break;
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case Intrinsic::bswap:
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// bswap(bswap(x)) -> x
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if (IntrinsicInst *Operand = dyn_cast<IntrinsicInst>(II->getOperand(1)))
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if (Operand->getIntrinsicID() == Intrinsic::bswap)
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return ReplaceInstUsesWith(CI, Operand->getOperand(1));
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break;
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case Intrinsic::ppc_altivec_lvx:
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case Intrinsic::ppc_altivec_lvxl:
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case Intrinsic::x86_sse_loadu_ps:
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case Intrinsic::x86_sse2_loadu_pd:
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case Intrinsic::x86_sse2_loadu_dq:
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// Turn PPC lvx -> load if the pointer is known aligned.
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// Turn X86 loadups -> load if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
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Value *Ptr = InsertBitCastBefore(II->getOperand(1),
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PointerType::getUnqual(II->getType()),
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CI);
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return new LoadInst(Ptr);
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}
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break;
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case Intrinsic::ppc_altivec_stvx:
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case Intrinsic::ppc_altivec_stvxl:
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// Turn stvx -> store if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(2), 16) >= 16) {
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const Type *OpPtrTy =
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PointerType::getUnqual(II->getOperand(1)->getType());
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Value *Ptr = InsertBitCastBefore(II->getOperand(2), OpPtrTy, CI);
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return new StoreInst(II->getOperand(1), Ptr);
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}
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break;
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case Intrinsic::x86_sse_storeu_ps:
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case Intrinsic::x86_sse2_storeu_pd:
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case Intrinsic::x86_sse2_storeu_dq:
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case Intrinsic::x86_sse2_storel_dq:
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// Turn X86 storeu -> store if the pointer is known aligned.
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if (GetOrEnforceKnownAlignment(II->getOperand(1), 16) >= 16) {
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const Type *OpPtrTy =
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PointerType::getUnqual(II->getOperand(2)->getType());
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Value *Ptr = InsertBitCastBefore(II->getOperand(1), OpPtrTy, CI);
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return new StoreInst(II->getOperand(2), Ptr);
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}
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break;
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case Intrinsic::x86_sse_cvttss2si: {
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// These intrinsics only demands the 0th element of its input vector. If
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// we can simplify the input based on that, do so now.
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uint64_t UndefElts;
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if (Value *V = SimplifyDemandedVectorElts(II->getOperand(1), 1,
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UndefElts)) {
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II->setOperand(1, V);
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return II;
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}
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break;
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}
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case Intrinsic::ppc_altivec_vperm:
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// Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
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if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getOperand(3))) {
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assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!");
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case Intrinsic::ppc_altivec_vperm:
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// Turn vperm(V1,V2,mask) -> shuffle(V1,V2,mask) if mask is a constant.
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if (ConstantVector *Mask = dyn_cast<ConstantVector>(II->getOperand(3))) {
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assert(Mask->getNumOperands() == 16 && "Bad type for intrinsic!");
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// Check that all of the elements are integer constants or undefs.
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bool AllEltsOk = true;
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for (unsigned i = 0; i != 16; ++i) {
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if (!isa<ConstantInt>(Mask->getOperand(i)) &&
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!isa<UndefValue>(Mask->getOperand(i))) {
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AllEltsOk = false;
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break;
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}
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}
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if (AllEltsOk) {
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// Cast the input vectors to byte vectors.
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Value *Op0 =InsertBitCastBefore(II->getOperand(1),Mask->getType(),CI);
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Value *Op1 =InsertBitCastBefore(II->getOperand(2),Mask->getType(),CI);
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Value *Result = UndefValue::get(Op0->getType());
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// Only extract each element once.
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Value *ExtractedElts[32];
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memset(ExtractedElts, 0, sizeof(ExtractedElts));
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// Check that all of the elements are integer constants or undefs.
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bool AllEltsOk = true;
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for (unsigned i = 0; i != 16; ++i) {
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if (!isa<ConstantInt>(Mask->getOperand(i)) &&
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!isa<UndefValue>(Mask->getOperand(i))) {
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AllEltsOk = false;
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break;
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if (isa<UndefValue>(Mask->getOperand(i)))
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continue;
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unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue();
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Idx &= 31; // Match the hardware behavior.
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if (ExtractedElts[Idx] == 0) {
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Instruction *Elt =
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new ExtractElementInst(Idx < 16 ? Op0 : Op1, Idx&15, "tmp");
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InsertNewInstBefore(Elt, CI);
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ExtractedElts[Idx] = Elt;
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}
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}
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if (AllEltsOk) {
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// Cast the input vectors to byte vectors.
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Value *Op0 =InsertBitCastBefore(II->getOperand(1),Mask->getType(),CI);
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Value *Op1 =InsertBitCastBefore(II->getOperand(2),Mask->getType(),CI);
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Value *Result = UndefValue::get(Op0->getType());
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// Only extract each element once.
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Value *ExtractedElts[32];
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memset(ExtractedElts, 0, sizeof(ExtractedElts));
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for (unsigned i = 0; i != 16; ++i) {
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if (isa<UndefValue>(Mask->getOperand(i)))
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continue;
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unsigned Idx=cast<ConstantInt>(Mask->getOperand(i))->getZExtValue();
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Idx &= 31; // Match the hardware behavior.
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if (ExtractedElts[Idx] == 0) {
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Instruction *Elt =
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new ExtractElementInst(Idx < 16 ? Op0 : Op1, Idx&15, "tmp");
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InsertNewInstBefore(Elt, CI);
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ExtractedElts[Idx] = Elt;
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}
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// Insert this value into the result vector.
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Result = InsertElementInst::Create(Result, ExtractedElts[Idx],
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i, "tmp");
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InsertNewInstBefore(cast<Instruction>(Result), CI);
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}
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return CastInst::Create(Instruction::BitCast, Result, CI.getType());
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// Insert this value into the result vector.
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Result = InsertElementInst::Create(Result, ExtractedElts[Idx],
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i, "tmp");
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InsertNewInstBefore(cast<Instruction>(Result), CI);
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}
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return CastInst::Create(Instruction::BitCast, Result, CI.getType());
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}
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break;
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}
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break;
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case Intrinsic::stackrestore: {
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// If the save is right next to the restore, remove the restore. This can
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// happen when variable allocas are DCE'd.
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if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getOperand(1))) {
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if (SS->getIntrinsicID() == Intrinsic::stacksave) {
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BasicBlock::iterator BI = SS;
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if (&*++BI == II)
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return EraseInstFromFunction(CI);
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}
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case Intrinsic::stackrestore: {
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// If the save is right next to the restore, remove the restore. This can
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// happen when variable allocas are DCE'd.
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if (IntrinsicInst *SS = dyn_cast<IntrinsicInst>(II->getOperand(1))) {
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if (SS->getIntrinsicID() == Intrinsic::stacksave) {
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BasicBlock::iterator BI = SS;
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if (&*++BI == II)
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return EraseInstFromFunction(CI);
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}
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// Scan down this block to see if there is another stack restore in the
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// same block without an intervening call/alloca.
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BasicBlock::iterator BI = II;
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TerminatorInst *TI = II->getParent()->getTerminator();
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bool CannotRemove = false;
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for (++BI; &*BI != TI; ++BI) {
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if (isa<AllocaInst>(BI)) {
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}
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// Scan down this block to see if there is another stack restore in the
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// same block without an intervening call/alloca.
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BasicBlock::iterator BI = II;
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TerminatorInst *TI = II->getParent()->getTerminator();
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bool CannotRemove = false;
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for (++BI; &*BI != TI; ++BI) {
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if (isa<AllocaInst>(BI)) {
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CannotRemove = true;
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break;
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}
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if (isa<CallInst>(BI)) {
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if (!isa<IntrinsicInst>(BI)) {
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CannotRemove = true;
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break;
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}
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if (isa<CallInst>(BI)) {
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if (!isa<IntrinsicInst>(BI)) {
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CannotRemove = true;
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break;
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}
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// If there is a stackrestore below this one, remove this one.
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return EraseInstFromFunction(CI);
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}
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}
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// If the stack restore is in a return/unwind block and if there are no
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// allocas or calls between the restore and the return, nuke the restore.
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if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI)))
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// If there is a stackrestore below this one, remove this one.
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return EraseInstFromFunction(CI);
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break;
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}
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}
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}
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// If the stack restore is in a return/unwind block and if there are no
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// allocas or calls between the restore and the return, nuke the restore.
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if (!CannotRemove && (isa<ReturnInst>(TI) || isa<UnwindInst>(TI)))
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return EraseInstFromFunction(CI);
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break;
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}
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}
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return visitCallSite(II);
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@ -1,7 +1,5 @@
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | \
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; RUN: grep ret | count 3
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | \
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; RUN: not grep call.*bswap
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep ret | count 6
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; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep call.*bswap
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define i1 @test1(i16 %tmp2) {
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%tmp10 = call i16 @llvm.bswap.i16( i16 %tmp2 ) ; <i16> [#uses=1]
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@ -27,3 +25,28 @@ declare i64 @llvm.bswap.i64(i64)
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declare i16 @llvm.bswap.i16(i16)
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; rdar://5992453
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; A & 255
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define i32 @test4(i32 %a) nounwind {
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entry:
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%tmp2 = tail call i32 @llvm.bswap.i32( i32 %a )
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%tmp4 = lshr i32 %tmp2, 24
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ret i32 %tmp4
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}
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; A
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define i32 @test5(i32 %a) nounwind {
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entry:
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%tmp2 = tail call i32 @llvm.bswap.i32( i32 %a )
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%tmp4 = tail call i32 @llvm.bswap.i32( i32 %tmp2 )
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ret i32 %tmp4
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}
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; a >> 24
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define i32 @test6(i32 %a) nounwind {
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entry:
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%tmp2 = tail call i32 @llvm.bswap.i32( i32 %a )
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%tmp4 = and i32 %tmp2, 255
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ret i32 %tmp4
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}
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