//===- DXILIntrinsicExpansion.cpp - Prepare LLVM Module for DXIL encoding--===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file This file contains DXIL intrinsic expansions for those that don't have
// opcodes in DirectX Intermediate Language (DXIL).
//===----------------------------------------------------------------------===//
#include "DXILIntrinsicExpansion.h"
#include "DirectX.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/DXILResource.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicsDirectX.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/Pass.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#define DEBUG_TYPE "dxil-intrinsic-expansion"
using namespace llvm;
class DXILIntrinsicExpansionLegacy : public ModulePass {
public:
bool runOnModule(Module &M) override;
DXILIntrinsicExpansionLegacy() : ModulePass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override;
static char ID; // Pass identification.
};
static bool isIntrinsicExpansion(Function &F) {
switch (F.getIntrinsicID()) {
case Intrinsic::abs:
case Intrinsic::atan2:
case Intrinsic::exp:
case Intrinsic::log:
case Intrinsic::log10:
case Intrinsic::pow:
case Intrinsic::dx_all:
case Intrinsic::dx_any:
case Intrinsic::dx_clamp:
case Intrinsic::dx_uclamp:
case Intrinsic::dx_lerp:
case Intrinsic::dx_length:
case Intrinsic::dx_normalize:
case Intrinsic::dx_fdot:
case Intrinsic::dx_sdot:
case Intrinsic::dx_udot:
case Intrinsic::dx_sign:
case Intrinsic::dx_step:
return true;
}
return false;
}
static Value *expandAbs(CallInst *Orig) {
Value *X = Orig->getOperand(0);
IRBuilder<> Builder(Orig);
Type *Ty = X->getType();
Type *EltTy = Ty->getScalarType();
Constant *Zero = Ty->isVectorTy()
? ConstantVector::getSplat(
ElementCount::getFixed(
cast<FixedVectorType>(Ty)->getNumElements()),
ConstantInt::get(EltTy, 0))
: ConstantInt::get(EltTy, 0);
auto *V = Builder.CreateSub(Zero, X);
return Builder.CreateIntrinsic(Ty, Intrinsic::smax, {X, V}, nullptr,
"dx.max");
}
// Create appropriate DXIL float dot intrinsic for the given A and B operands
// The appropriate opcode will be determined by the size of the operands
// The dot product is placed in the position indicated by Orig
static Value *expandFloatDotIntrinsic(CallInst *Orig, Value *A, Value *B) {
Type *ATy = A->getType();
[[maybe_unused]] Type *BTy = B->getType();
assert(ATy->isVectorTy() && BTy->isVectorTy());
IRBuilder<> Builder(Orig);
auto *AVec = dyn_cast<FixedVectorType>(ATy);
assert(ATy->getScalarType()->isFloatingPointTy());
Intrinsic::ID DotIntrinsic = Intrinsic::dx_dot4;
switch (AVec->getNumElements()) {
case 2:
DotIntrinsic = Intrinsic::dx_dot2;
break;
case 3:
DotIntrinsic = Intrinsic::dx_dot3;
break;
case 4:
DotIntrinsic = Intrinsic::dx_dot4;
break;
default:
report_fatal_error(
Twine("Invalid dot product input vector: length is outside 2-4"),
/* gen_crash_diag=*/false);
return nullptr;
}
return Builder.CreateIntrinsic(ATy->getScalarType(), DotIntrinsic,
ArrayRef<Value *>{A, B}, nullptr, "dot");
}
// Create the appropriate DXIL float dot intrinsic for the operands of Orig
// The appropriate opcode will be determined by the size of the operands
// The dot product is placed in the position indicated by Orig
static Value *expandFloatDotIntrinsic(CallInst *Orig) {
return expandFloatDotIntrinsic(Orig, Orig->getOperand(0),
Orig->getOperand(1));
}
// Expand integer dot product to multiply and add ops
static Value *expandIntegerDotIntrinsic(CallInst *Orig,
Intrinsic::ID DotIntrinsic) {
assert(DotIntrinsic == Intrinsic::dx_sdot ||
DotIntrinsic == Intrinsic::dx_udot);
Value *A = Orig->getOperand(0);
Value *B = Orig->getOperand(1);
Type *ATy = A->getType();
[[maybe_unused]] Type *BTy = B->getType();
assert(ATy->isVectorTy() && BTy->isVectorTy());
IRBuilder<> Builder(Orig);
auto *AVec = dyn_cast<FixedVectorType>(ATy);
assert(ATy->getScalarType()->isIntegerTy());
Value *Result;
Intrinsic::ID MadIntrinsic = DotIntrinsic == Intrinsic::dx_sdot
? Intrinsic::dx_imad
: Intrinsic::dx_umad;
Value *Elt0 = Builder.CreateExtractElement(A, (uint64_t)0);
Value *Elt1 = Builder.CreateExtractElement(B, (uint64_t)0);
Result = Builder.CreateMul(Elt0, Elt1);
for (unsigned I = 1; I < AVec->getNumElements(); I++) {
Elt0 = Builder.CreateExtractElement(A, I);
Elt1 = Builder.CreateExtractElement(B, I);
Result = Builder.CreateIntrinsic(Result->getType(), MadIntrinsic,
ArrayRef<Value *>{Elt0, Elt1, Result},
nullptr, "dx.mad");
}
return Result;
}
static Value *expandExpIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
IRBuilder<> Builder(Orig);
Type *Ty = X->getType();
Type *EltTy = Ty->getScalarType();
Constant *Log2eConst =
Ty->isVectorTy() ? ConstantVector::getSplat(
ElementCount::getFixed(
cast<FixedVectorType>(Ty)->getNumElements()),
ConstantFP::get(EltTy, numbers::log2ef))
: ConstantFP::get(EltTy, numbers::log2ef);
Value *NewX = Builder.CreateFMul(Log2eConst, X);
auto *Exp2Call =
Builder.CreateIntrinsic(Ty, Intrinsic::exp2, {NewX}, nullptr, "dx.exp2");
Exp2Call->setTailCall(Orig->isTailCall());
Exp2Call->setAttributes(Orig->getAttributes());
return Exp2Call;
}
static Value *expandAnyOrAllIntrinsic(CallInst *Orig,
Intrinsic::ID intrinsicId) {
Value *X = Orig->getOperand(0);
IRBuilder<> Builder(Orig);
Type *Ty = X->getType();
Type *EltTy = Ty->getScalarType();
auto ApplyOp = [&Builder](Intrinsic::ID IntrinsicId, Value *Result,
Value *Elt) {
if (IntrinsicId == Intrinsic::dx_any)
return Builder.CreateOr(Result, Elt);
assert(IntrinsicId == Intrinsic::dx_all);
return Builder.CreateAnd(Result, Elt);
};
Value *Result = nullptr;
if (!Ty->isVectorTy()) {
Result = EltTy->isFloatingPointTy()
? Builder.CreateFCmpUNE(X, ConstantFP::get(EltTy, 0))
: Builder.CreateICmpNE(X, ConstantInt::get(EltTy, 0));
} else {
auto *XVec = dyn_cast<FixedVectorType>(Ty);
Value *Cond =
EltTy->isFloatingPointTy()
? Builder.CreateFCmpUNE(
X, ConstantVector::getSplat(
ElementCount::getFixed(XVec->getNumElements()),
ConstantFP::get(EltTy, 0)))
: Builder.CreateICmpNE(
X, ConstantVector::getSplat(
ElementCount::getFixed(XVec->getNumElements()),
ConstantInt::get(EltTy, 0)));
Result = Builder.CreateExtractElement(Cond, (uint64_t)0);
for (unsigned I = 1; I < XVec->getNumElements(); I++) {
Value *Elt = Builder.CreateExtractElement(Cond, I);
Result = ApplyOp(intrinsicId, Result, Elt);
}
}
return Result;
}
static Value *expandLengthIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
IRBuilder<> Builder(Orig);
Type *Ty = X->getType();
Type *EltTy = Ty->getScalarType();
// Though dx.length does work on scalar type, we can optimize it to just emit
// fabs, in CGBuiltin.cpp. We shouldn't see a scalar type here because
// CGBuiltin.cpp should have emitted a fabs call.
Value *Elt = Builder.CreateExtractElement(X, (uint64_t)0);
auto *XVec = dyn_cast<FixedVectorType>(Ty);
unsigned XVecSize = XVec->getNumElements();
if (!(Ty->isVectorTy() && XVecSize > 1))
report_fatal_error(Twine("Invalid input type for length intrinsic"),
/* gen_crash_diag=*/false);
Value *Sum = Builder.CreateFMul(Elt, Elt);
for (unsigned I = 1; I < XVecSize; I++) {
Elt = Builder.CreateExtractElement(X, I);
Value *Mul = Builder.CreateFMul(Elt, Elt);
Sum = Builder.CreateFAdd(Sum, Mul);
}
return Builder.CreateIntrinsic(EltTy, Intrinsic::sqrt, ArrayRef<Value *>{Sum},
nullptr, "elt.sqrt");
}
static Value *expandLerpIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
Value *Y = Orig->getOperand(1);
Value *S = Orig->getOperand(2);
IRBuilder<> Builder(Orig);
auto *V = Builder.CreateFSub(Y, X);
V = Builder.CreateFMul(S, V);
return Builder.CreateFAdd(X, V, "dx.lerp");
}
static Value *expandLogIntrinsic(CallInst *Orig,
float LogConstVal = numbers::ln2f) {
Value *X = Orig->getOperand(0);
IRBuilder<> Builder(Orig);
Type *Ty = X->getType();
Type *EltTy = Ty->getScalarType();
Constant *Ln2Const =
Ty->isVectorTy() ? ConstantVector::getSplat(
ElementCount::getFixed(
cast<FixedVectorType>(Ty)->getNumElements()),
ConstantFP::get(EltTy, LogConstVal))
: ConstantFP::get(EltTy, LogConstVal);
auto *Log2Call =
Builder.CreateIntrinsic(Ty, Intrinsic::log2, {X}, nullptr, "elt.log2");
Log2Call->setTailCall(Orig->isTailCall());
Log2Call->setAttributes(Orig->getAttributes());
return Builder.CreateFMul(Ln2Const, Log2Call);
}
static Value *expandLog10Intrinsic(CallInst *Orig) {
return expandLogIntrinsic(Orig, numbers::ln2f / numbers::ln10f);
}
// Use dot product of vector operand with itself to calculate the length.
// Divide the vector by that length to normalize it.
static Value *expandNormalizeIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
Type *Ty = Orig->getType();
Type *EltTy = Ty->getScalarType();
IRBuilder<> Builder(Orig);
auto *XVec = dyn_cast<FixedVectorType>(Ty);
if (!XVec) {
if (auto *constantFP = dyn_cast<ConstantFP>(X)) {
const APFloat &fpVal = constantFP->getValueAPF();
if (fpVal.isZero())
report_fatal_error(Twine("Invalid input scalar: length is zero"),
/* gen_crash_diag=*/false);
}
return Builder.CreateFDiv(X, X);
}
Value *DotProduct = expandFloatDotIntrinsic(Orig, X, X);
// verify that the length is non-zero
// (if the dot product is non-zero, then the length is non-zero)
if (auto *constantFP = dyn_cast<ConstantFP>(DotProduct)) {
const APFloat &fpVal = constantFP->getValueAPF();
if (fpVal.isZero())
report_fatal_error(Twine("Invalid input vector: length is zero"),
/* gen_crash_diag=*/false);
}
Value *Multiplicand = Builder.CreateIntrinsic(EltTy, Intrinsic::dx_rsqrt,
ArrayRef<Value *>{DotProduct},
nullptr, "dx.rsqrt");
Value *MultiplicandVec =
Builder.CreateVectorSplat(XVec->getNumElements(), Multiplicand);
return Builder.CreateFMul(X, MultiplicandVec);
}
static Value *expandAtan2Intrinsic(CallInst *Orig) {
Value *Y = Orig->getOperand(0);
Value *X = Orig->getOperand(1);
Type *Ty = X->getType();
IRBuilder<> Builder(Orig);
Builder.setFastMathFlags(Orig->getFastMathFlags());
Value *Tan = Builder.CreateFDiv(Y, X);
CallInst *Atan =
Builder.CreateIntrinsic(Ty, Intrinsic::atan, {Tan}, nullptr, "Elt.Atan");
Atan->setTailCall(Orig->isTailCall());
Atan->setAttributes(Orig->getAttributes());
// Modify atan result based on https://en.wikipedia.org/wiki/Atan2.
Constant *Pi = ConstantFP::get(Ty, llvm::numbers::pi);
Constant *HalfPi = ConstantFP::get(Ty, llvm::numbers::pi / 2);
Constant *NegHalfPi = ConstantFP::get(Ty, -llvm::numbers::pi / 2);
Constant *Zero = ConstantFP::get(Ty, 0);
Value *AtanAddPi = Builder.CreateFAdd(Atan, Pi);
Value *AtanSubPi = Builder.CreateFSub(Atan, Pi);
// x > 0 -> atan.
Value *Result = Atan;
Value *XLt0 = Builder.CreateFCmpOLT(X, Zero);
Value *XEq0 = Builder.CreateFCmpOEQ(X, Zero);
Value *YGe0 = Builder.CreateFCmpOGE(Y, Zero);
Value *YLt0 = Builder.CreateFCmpOLT(Y, Zero);
// x < 0, y >= 0 -> atan + pi.
Value *XLt0AndYGe0 = Builder.CreateAnd(XLt0, YGe0);
Result = Builder.CreateSelect(XLt0AndYGe0, AtanAddPi, Result);
// x < 0, y < 0 -> atan - pi.
Value *XLt0AndYLt0 = Builder.CreateAnd(XLt0, YLt0);
Result = Builder.CreateSelect(XLt0AndYLt0, AtanSubPi, Result);
// x == 0, y < 0 -> -pi/2
Value *XEq0AndYLt0 = Builder.CreateAnd(XEq0, YLt0);
Result = Builder.CreateSelect(XEq0AndYLt0, NegHalfPi, Result);
// x == 0, y > 0 -> pi/2
Value *XEq0AndYGe0 = Builder.CreateAnd(XEq0, YGe0);
Result = Builder.CreateSelect(XEq0AndYGe0, HalfPi, Result);
return Result;
}
static Value *expandPowIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
Value *Y = Orig->getOperand(1);
Type *Ty = X->getType();
IRBuilder<> Builder(Orig);
auto *Log2Call =
Builder.CreateIntrinsic(Ty, Intrinsic::log2, {X}, nullptr, "elt.log2");
auto *Mul = Builder.CreateFMul(Log2Call, Y);
auto *Exp2Call =
Builder.CreateIntrinsic(Ty, Intrinsic::exp2, {Mul}, nullptr, "elt.exp2");
Exp2Call->setTailCall(Orig->isTailCall());
Exp2Call->setAttributes(Orig->getAttributes());
return Exp2Call;
}
static Value *expandStepIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
Value *Y = Orig->getOperand(1);
Type *Ty = X->getType();
IRBuilder<> Builder(Orig);
Constant *One = ConstantFP::get(Ty->getScalarType(), 1.0);
Constant *Zero = ConstantFP::get(Ty->getScalarType(), 0.0);
Value *Cond = Builder.CreateFCmpOLT(Y, X);
if (Ty != Ty->getScalarType()) {
auto *XVec = dyn_cast<FixedVectorType>(Ty);
One = ConstantVector::getSplat(
ElementCount::getFixed(XVec->getNumElements()), One);
Zero = ConstantVector::getSplat(
ElementCount::getFixed(XVec->getNumElements()), Zero);
}
return Builder.CreateSelect(Cond, Zero, One);
}
static Intrinsic::ID getMaxForClamp(Type *ElemTy,
Intrinsic::ID ClampIntrinsic) {
if (ClampIntrinsic == Intrinsic::dx_uclamp)
return Intrinsic::umax;
assert(ClampIntrinsic == Intrinsic::dx_clamp);
if (ElemTy->isVectorTy())
ElemTy = ElemTy->getScalarType();
if (ElemTy->isIntegerTy())
return Intrinsic::smax;
assert(ElemTy->isFloatingPointTy());
return Intrinsic::maxnum;
}
static Intrinsic::ID getMinForClamp(Type *ElemTy,
Intrinsic::ID ClampIntrinsic) {
if (ClampIntrinsic == Intrinsic::dx_uclamp)
return Intrinsic::umin;
assert(ClampIntrinsic == Intrinsic::dx_clamp);
if (ElemTy->isVectorTy())
ElemTy = ElemTy->getScalarType();
if (ElemTy->isIntegerTy())
return Intrinsic::smin;
assert(ElemTy->isFloatingPointTy());
return Intrinsic::minnum;
}
static Value *expandClampIntrinsic(CallInst *Orig,
Intrinsic::ID ClampIntrinsic) {
Value *X = Orig->getOperand(0);
Value *Min = Orig->getOperand(1);
Value *Max = Orig->getOperand(2);
Type *Ty = X->getType();
IRBuilder<> Builder(Orig);
auto *MaxCall = Builder.CreateIntrinsic(
Ty, getMaxForClamp(Ty, ClampIntrinsic), {X, Min}, nullptr, "dx.max");
return Builder.CreateIntrinsic(Ty, getMinForClamp(Ty, ClampIntrinsic),
{MaxCall, Max}, nullptr, "dx.min");
}
static Value *expandSignIntrinsic(CallInst *Orig) {
Value *X = Orig->getOperand(0);
Type *Ty = X->getType();
Type *ScalarTy = Ty->getScalarType();
Type *RetTy = Orig->getType();
Constant *Zero = Constant::getNullValue(Ty);
IRBuilder<> Builder(Orig);
Value *GT;
Value *LT;
if (ScalarTy->isFloatingPointTy()) {
GT = Builder.CreateFCmpOLT(Zero, X);
LT = Builder.CreateFCmpOLT(X, Zero);
} else {
assert(ScalarTy->isIntegerTy());
GT = Builder.CreateICmpSLT(Zero, X);
LT = Builder.CreateICmpSLT(X, Zero);
}
Value *ZextGT = Builder.CreateZExt(GT, RetTy);
Value *ZextLT = Builder.CreateZExt(LT, RetTy);
return Builder.CreateSub(ZextGT, ZextLT);
}
static bool expandIntrinsic(Function &F, CallInst *Orig) {
Value *Result = nullptr;
Intrinsic::ID IntrinsicId = F.getIntrinsicID();
switch (IntrinsicId) {
case Intrinsic::abs:
Result = expandAbs(Orig);
break;
case Intrinsic::atan2:
Result = expandAtan2Intrinsic(Orig);
break;
case Intrinsic::exp:
Result = expandExpIntrinsic(Orig);
break;
case Intrinsic::log:
Result = expandLogIntrinsic(Orig);
break;
case Intrinsic::log10:
Result = expandLog10Intrinsic(Orig);
break;
case Intrinsic::pow:
Result = expandPowIntrinsic(Orig);
break;
case Intrinsic::dx_all:
case Intrinsic::dx_any:
Result = expandAnyOrAllIntrinsic(Orig, IntrinsicId);
break;
case Intrinsic::dx_uclamp:
case Intrinsic::dx_clamp:
Result = expandClampIntrinsic(Orig, IntrinsicId);
break;
case Intrinsic::dx_lerp:
Result = expandLerpIntrinsic(Orig);
break;
case Intrinsic::dx_length:
Result = expandLengthIntrinsic(Orig);
break;
case Intrinsic::dx_normalize:
Result = expandNormalizeIntrinsic(Orig);
break;
case Intrinsic::dx_fdot:
Result = expandFloatDotIntrinsic(Orig);
break;
case Intrinsic::dx_sdot:
case Intrinsic::dx_udot:
Result = expandIntegerDotIntrinsic(Orig, IntrinsicId);
break;
case Intrinsic::dx_sign:
Result = expandSignIntrinsic(Orig);
break;
case Intrinsic::dx_step:
Result = expandStepIntrinsic(Orig);
}
if (Result) {
Orig->replaceAllUsesWith(Result);
Orig->eraseFromParent();
return true;
}
return false;
}
static bool expansionIntrinsics(Module &M) {
for (auto &F : make_early_inc_range(M.functions())) {
if (!isIntrinsicExpansion(F))
continue;
bool IntrinsicExpanded = false;
for (User *U : make_early_inc_range(F.users())) {
auto *IntrinsicCall = dyn_cast<CallInst>(U);
if (!IntrinsicCall)
continue;
IntrinsicExpanded = expandIntrinsic(F, IntrinsicCall);
}
if (F.user_empty() && IntrinsicExpanded)
F.eraseFromParent();
}
return true;
}
PreservedAnalyses DXILIntrinsicExpansion::run(Module &M,
ModuleAnalysisManager &) {
if (expansionIntrinsics(M))
return PreservedAnalyses::none();
return PreservedAnalyses::all();
}
bool DXILIntrinsicExpansionLegacy::runOnModule(Module &M) {
return expansionIntrinsics(M);
}
void DXILIntrinsicExpansionLegacy::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<DXILResourceWrapperPass>();
}
char DXILIntrinsicExpansionLegacy::ID = 0;
INITIALIZE_PASS_BEGIN(DXILIntrinsicExpansionLegacy, DEBUG_TYPE,
"DXIL Intrinsic Expansion", false, false)
INITIALIZE_PASS_END(DXILIntrinsicExpansionLegacy, DEBUG_TYPE,
"DXIL Intrinsic Expansion", false, false)
ModulePass *llvm::createDXILIntrinsicExpansionLegacyPass() {
return new DXILIntrinsicExpansionLegacy();
}
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