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llvm-for-llvmta/lib/CodeGen/IntrinsicLowering.cpp

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2022-04-25 10:02:23 +02:00
//===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the IntrinsicLowering class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/IntrinsicLowering.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
/// This function is used when we want to lower an intrinsic call to a call of
/// an external function. This handles hard cases such as when there was already
/// a prototype for the external function, but that prototype doesn't match the
/// arguments we expect to pass in.
template <class ArgIt>
static CallInst *ReplaceCallWith(const char *NewFn, CallInst *CI,
ArgIt ArgBegin, ArgIt ArgEnd,
Type *RetTy) {
// If we haven't already looked up this function, check to see if the
// program already contains a function with this name.
Module *M = CI->getModule();
// Get or insert the definition now.
std::vector<Type *> ParamTys;
for (ArgIt I = ArgBegin; I != ArgEnd; ++I)
ParamTys.push_back((*I)->getType());
FunctionCallee FCache =
M->getOrInsertFunction(NewFn, FunctionType::get(RetTy, ParamTys, false));
IRBuilder<> Builder(CI->getParent(), CI->getIterator());
SmallVector<Value *, 8> Args(ArgBegin, ArgEnd);
CallInst *NewCI = Builder.CreateCall(FCache, Args);
NewCI->setName(CI->getName());
if (!CI->use_empty())
CI->replaceAllUsesWith(NewCI);
return NewCI;
}
/// Emit the code to lower bswap of V before the specified instruction IP.
static Value *LowerBSWAP(LLVMContext &Context, Value *V, Instruction *IP) {
assert(V->getType()->isIntOrIntVectorTy() && "Can't bswap a non-integer type!");
unsigned BitSize = V->getType()->getScalarSizeInBits();
IRBuilder<> Builder(IP);
switch(BitSize) {
default: llvm_unreachable("Unhandled type size of value to byteswap!");
case 16: {
Value *Tmp1 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
"bswap.2");
Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
"bswap.1");
V = Builder.CreateOr(Tmp1, Tmp2, "bswap.i16");
break;
}
case 32: {
Value *Tmp4 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
"bswap.4");
Value *Tmp3 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
"bswap.3");
Value *Tmp2 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
"bswap.2");
Value *Tmp1 = Builder.CreateLShr(V,ConstantInt::get(V->getType(), 24),
"bswap.1");
Tmp3 = Builder.CreateAnd(Tmp3,
ConstantInt::get(V->getType(), 0xFF0000),
"bswap.and3");
Tmp2 = Builder.CreateAnd(Tmp2,
ConstantInt::get(V->getType(), 0xFF00),
"bswap.and2");
Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or1");
Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or2");
V = Builder.CreateOr(Tmp4, Tmp2, "bswap.i32");
break;
}
case 64: {
Value *Tmp8 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 56),
"bswap.8");
Value *Tmp7 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 40),
"bswap.7");
Value *Tmp6 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 24),
"bswap.6");
Value *Tmp5 = Builder.CreateShl(V, ConstantInt::get(V->getType(), 8),
"bswap.5");
Value* Tmp4 = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 8),
"bswap.4");
Value* Tmp3 = Builder.CreateLShr(V,
ConstantInt::get(V->getType(), 24),
"bswap.3");
Value* Tmp2 = Builder.CreateLShr(V,
ConstantInt::get(V->getType(), 40),
"bswap.2");
Value* Tmp1 = Builder.CreateLShr(V,
ConstantInt::get(V->getType(), 56),
"bswap.1");
Tmp7 = Builder.CreateAnd(Tmp7,
ConstantInt::get(V->getType(),
0xFF000000000000ULL),
"bswap.and7");
Tmp6 = Builder.CreateAnd(Tmp6,
ConstantInt::get(V->getType(),
0xFF0000000000ULL),
"bswap.and6");
Tmp5 = Builder.CreateAnd(Tmp5,
ConstantInt::get(V->getType(),
0xFF00000000ULL),
"bswap.and5");
Tmp4 = Builder.CreateAnd(Tmp4,
ConstantInt::get(V->getType(),
0xFF000000ULL),
"bswap.and4");
Tmp3 = Builder.CreateAnd(Tmp3,
ConstantInt::get(V->getType(),
0xFF0000ULL),
"bswap.and3");
Tmp2 = Builder.CreateAnd(Tmp2,
ConstantInt::get(V->getType(),
0xFF00ULL),
"bswap.and2");
Tmp8 = Builder.CreateOr(Tmp8, Tmp7, "bswap.or1");
Tmp6 = Builder.CreateOr(Tmp6, Tmp5, "bswap.or2");
Tmp4 = Builder.CreateOr(Tmp4, Tmp3, "bswap.or3");
Tmp2 = Builder.CreateOr(Tmp2, Tmp1, "bswap.or4");
Tmp8 = Builder.CreateOr(Tmp8, Tmp6, "bswap.or5");
Tmp4 = Builder.CreateOr(Tmp4, Tmp2, "bswap.or6");
V = Builder.CreateOr(Tmp8, Tmp4, "bswap.i64");
break;
}
}
return V;
}
/// Emit the code to lower ctpop of V before the specified instruction IP.
static Value *LowerCTPOP(LLVMContext &Context, Value *V, Instruction *IP) {
assert(V->getType()->isIntegerTy() && "Can't ctpop a non-integer type!");
static const uint64_t MaskValues[6] = {
0x5555555555555555ULL, 0x3333333333333333ULL,
0x0F0F0F0F0F0F0F0FULL, 0x00FF00FF00FF00FFULL,
0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL
};
IRBuilder<> Builder(IP);
unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
unsigned WordSize = (BitSize + 63) / 64;
Value *Count = ConstantInt::get(V->getType(), 0);
for (unsigned n = 0; n < WordSize; ++n) {
Value *PartValue = V;
for (unsigned i = 1, ct = 0; i < (BitSize>64 ? 64 : BitSize);
i <<= 1, ++ct) {
Value *MaskCst = ConstantInt::get(V->getType(), MaskValues[ct]);
Value *LHS = Builder.CreateAnd(PartValue, MaskCst, "cppop.and1");
Value *VShift = Builder.CreateLShr(PartValue,
ConstantInt::get(V->getType(), i),
"ctpop.sh");
Value *RHS = Builder.CreateAnd(VShift, MaskCst, "cppop.and2");
PartValue = Builder.CreateAdd(LHS, RHS, "ctpop.step");
}
Count = Builder.CreateAdd(PartValue, Count, "ctpop.part");
if (BitSize > 64) {
V = Builder.CreateLShr(V, ConstantInt::get(V->getType(), 64),
"ctpop.part.sh");
BitSize -= 64;
}
}
return Count;
}
/// Emit the code to lower ctlz of V before the specified instruction IP.
static Value *LowerCTLZ(LLVMContext &Context, Value *V, Instruction *IP) {
IRBuilder<> Builder(IP);
unsigned BitSize = V->getType()->getPrimitiveSizeInBits();
for (unsigned i = 1; i < BitSize; i <<= 1) {
Value *ShVal = ConstantInt::get(V->getType(), i);
ShVal = Builder.CreateLShr(V, ShVal, "ctlz.sh");
V = Builder.CreateOr(V, ShVal, "ctlz.step");
}
V = Builder.CreateNot(V);
return LowerCTPOP(Context, V, IP);
}
static void ReplaceFPIntrinsicWithCall(CallInst *CI, const char *Fname,
const char *Dname,
const char *LDname) {
switch (CI->getArgOperand(0)->getType()->getTypeID()) {
default: llvm_unreachable("Invalid type in intrinsic");
case Type::FloatTyID:
ReplaceCallWith(Fname, CI, CI->arg_begin(), CI->arg_end(),
Type::getFloatTy(CI->getContext()));
break;
case Type::DoubleTyID:
ReplaceCallWith(Dname, CI, CI->arg_begin(), CI->arg_end(),
Type::getDoubleTy(CI->getContext()));
break;
case Type::X86_FP80TyID:
case Type::FP128TyID:
case Type::PPC_FP128TyID:
ReplaceCallWith(LDname, CI, CI->arg_begin(), CI->arg_end(),
CI->getArgOperand(0)->getType());
break;
}
}
void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
IRBuilder<> Builder(CI);
LLVMContext &Context = CI->getContext();
const Function *Callee = CI->getCalledFunction();
assert(Callee && "Cannot lower an indirect call!");
switch (Callee->getIntrinsicID()) {
case Intrinsic::not_intrinsic:
report_fatal_error("Cannot lower a call to a non-intrinsic function '"+
Callee->getName() + "'!");
default:
report_fatal_error("Code generator does not support intrinsic function '"+
Callee->getName()+"'!");
case Intrinsic::expect: {
// Just replace __builtin_expect(exp, c) with EXP.
Value *V = CI->getArgOperand(0);
CI->replaceAllUsesWith(V);
break;
}
case Intrinsic::ctpop:
CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI));
break;
case Intrinsic::bswap:
CI->replaceAllUsesWith(LowerBSWAP(Context, CI->getArgOperand(0), CI));
break;
case Intrinsic::ctlz:
CI->replaceAllUsesWith(LowerCTLZ(Context, CI->getArgOperand(0), CI));
break;
case Intrinsic::cttz: {
// cttz(x) -> ctpop(~X & (X-1))
Value *Src = CI->getArgOperand(0);
Value *NotSrc = Builder.CreateNot(Src);
NotSrc->setName(Src->getName() + ".not");
Value *SrcM1 = ConstantInt::get(Src->getType(), 1);
SrcM1 = Builder.CreateSub(Src, SrcM1);
Src = LowerCTPOP(Context, Builder.CreateAnd(NotSrc, SrcM1), CI);
CI->replaceAllUsesWith(Src);
break;
}
case Intrinsic::stacksave:
case Intrinsic::stackrestore: {
if (!Warned)
errs() << "WARNING: this target does not support the llvm.stack"
<< (Callee->getIntrinsicID() == Intrinsic::stacksave ?
"save" : "restore") << " intrinsic.\n";
Warned = true;
if (Callee->getIntrinsicID() == Intrinsic::stacksave)
CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
break;
}
case Intrinsic::get_dynamic_area_offset:
errs() << "WARNING: this target does not support the custom llvm.get."
"dynamic.area.offset. It is being lowered to a constant 0\n";
// Just lower it to a constant 0 because for most targets
// @llvm.get.dynamic.area.offset is lowered to zero.
CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 0));
break;
case Intrinsic::returnaddress:
case Intrinsic::frameaddress:
errs() << "WARNING: this target does not support the llvm."
<< (Callee->getIntrinsicID() == Intrinsic::returnaddress ?
"return" : "frame") << "address intrinsic.\n";
CI->replaceAllUsesWith(
ConstantPointerNull::get(cast<PointerType>(CI->getType())));
break;
case Intrinsic::addressofreturnaddress:
errs() << "WARNING: this target does not support the "
"llvm.addressofreturnaddress intrinsic.\n";
CI->replaceAllUsesWith(
ConstantPointerNull::get(cast<PointerType>(CI->getType())));
break;
case Intrinsic::prefetch:
break; // Simply strip out prefetches on unsupported architectures
case Intrinsic::pcmarker:
break; // Simply strip out pcmarker on unsupported architectures
case Intrinsic::readcyclecounter: {
errs() << "WARNING: this target does not support the llvm.readcyclecoun"
<< "ter intrinsic. It is being lowered to a constant 0\n";
CI->replaceAllUsesWith(ConstantInt::get(Type::getInt64Ty(Context), 0));
break;
}
case Intrinsic::dbg_declare:
case Intrinsic::dbg_label:
break; // Simply strip out debugging intrinsics
case Intrinsic::eh_typeid_for:
// Return something different to eh_selector.
CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
break;
case Intrinsic::annotation:
case Intrinsic::ptr_annotation:
// Just drop the annotation, but forward the value
CI->replaceAllUsesWith(CI->getOperand(0));
break;
case Intrinsic::assume:
case Intrinsic::experimental_noalias_scope_decl:
case Intrinsic::var_annotation:
break; // Strip out these intrinsics
case Intrinsic::memcpy: {
Type *IntPtr = DL.getIntPtrType(Context);
Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
/* isSigned */ false);
Value *Ops[3];
Ops[0] = CI->getArgOperand(0);
Ops[1] = CI->getArgOperand(1);
Ops[2] = Size;
ReplaceCallWith("memcpy", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
break;
}
case Intrinsic::memmove: {
Type *IntPtr = DL.getIntPtrType(Context);
Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
/* isSigned */ false);
Value *Ops[3];
Ops[0] = CI->getArgOperand(0);
Ops[1] = CI->getArgOperand(1);
Ops[2] = Size;
ReplaceCallWith("memmove", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
break;
}
case Intrinsic::memset: {
Value *Op0 = CI->getArgOperand(0);
Type *IntPtr = DL.getIntPtrType(Op0->getType());
Value *Size = Builder.CreateIntCast(CI->getArgOperand(2), IntPtr,
/* isSigned */ false);
Value *Ops[3];
Ops[0] = Op0;
// Extend the amount to i32.
Ops[1] = Builder.CreateIntCast(CI->getArgOperand(1),
Type::getInt32Ty(Context),
/* isSigned */ false);
Ops[2] = Size;
ReplaceCallWith("memset", CI, Ops, Ops+3, CI->getArgOperand(0)->getType());
break;
}
case Intrinsic::sqrt: {
ReplaceFPIntrinsicWithCall(CI, "sqrtf", "sqrt", "sqrtl");
break;
}
case Intrinsic::log: {
ReplaceFPIntrinsicWithCall(CI, "logf", "log", "logl");
break;
}
case Intrinsic::log2: {
ReplaceFPIntrinsicWithCall(CI, "log2f", "log2", "log2l");
break;
}
case Intrinsic::log10: {
ReplaceFPIntrinsicWithCall(CI, "log10f", "log10", "log10l");
break;
}
case Intrinsic::exp: {
ReplaceFPIntrinsicWithCall(CI, "expf", "exp", "expl");
break;
}
case Intrinsic::exp2: {
ReplaceFPIntrinsicWithCall(CI, "exp2f", "exp2", "exp2l");
break;
}
case Intrinsic::pow: {
ReplaceFPIntrinsicWithCall(CI, "powf", "pow", "powl");
break;
}
case Intrinsic::sin: {
ReplaceFPIntrinsicWithCall(CI, "sinf", "sin", "sinl");
break;
}
case Intrinsic::cos: {
ReplaceFPIntrinsicWithCall(CI, "cosf", "cos", "cosl");
break;
}
case Intrinsic::floor: {
ReplaceFPIntrinsicWithCall(CI, "floorf", "floor", "floorl");
break;
}
case Intrinsic::ceil: {
ReplaceFPIntrinsicWithCall(CI, "ceilf", "ceil", "ceill");
break;
}
case Intrinsic::trunc: {
ReplaceFPIntrinsicWithCall(CI, "truncf", "trunc", "truncl");
break;
}
case Intrinsic::round: {
ReplaceFPIntrinsicWithCall(CI, "roundf", "round", "roundl");
break;
}
case Intrinsic::roundeven: {
ReplaceFPIntrinsicWithCall(CI, "roundevenf", "roundeven", "roundevenl");
break;
}
case Intrinsic::copysign: {
ReplaceFPIntrinsicWithCall(CI, "copysignf", "copysign", "copysignl");
break;
}
case Intrinsic::flt_rounds:
// Lower to "round to the nearest"
if (!CI->getType()->isVoidTy())
CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 1));
break;
case Intrinsic::invariant_start:
case Intrinsic::lifetime_start:
// Discard region information.
CI->replaceAllUsesWith(UndefValue::get(CI->getType()));
break;
case Intrinsic::invariant_end:
case Intrinsic::lifetime_end:
// Discard region information.
break;
}
assert(CI->use_empty() &&
"Lowering should have eliminated any uses of the intrinsic call!");
CI->eraseFromParent();
}
bool IntrinsicLowering::LowerToByteSwap(CallInst *CI) {
// Verify this is a simple bswap.
if (CI->getNumArgOperands() != 1 ||
CI->getType() != CI->getArgOperand(0)->getType() ||
!CI->getType()->isIntegerTy())
return false;
IntegerType *Ty = dyn_cast<IntegerType>(CI->getType());
if (!Ty)
return false;
// Okay, we can do this xform, do so now.
Module *M = CI->getModule();
Function *Int = Intrinsic::getDeclaration(M, Intrinsic::bswap, Ty);
Value *Op = CI->getArgOperand(0);
Op = CallInst::Create(Int, Op, CI->getName(), CI);
CI->replaceAllUsesWith(Op);
CI->eraseFromParent();
return true;
}