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//===-- IntegerDivision.cpp - Expand integer division ---------------------===//
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// The LLVM Compiler Infrastructure
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//===----------------------------------------------------------------------===//
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// This file contains an implementation of 32bit and 64bit scalar integer
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// division for targets that don't have native support. It's largely derived
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// from compiler-rt's implementations of __udivsi3 and __udivmoddi4,
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// but hand-tuned for targets that prefer less control flow.
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/IntegerDivision.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Intrinsics.h"
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#define DEBUG_TYPE "integer-division"
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/// Generate code to compute the remainder of two signed integers. Returns the
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/// remainder, which will have the sign of the dividend. Builder's insert point
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/// should be pointing where the caller wants code generated, e.g. at the srem
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/// instruction. This will generate a urem in the process, and Builder's insert
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/// point will be pointing at the uren (if present, i.e. not folded), ready to
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/// be expanded if the user wishes
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static Value *generateSignedRemainderCode(Value *Dividend, Value *Divisor,
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IRBuilder<> &Builder) {
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unsigned BitWidth = Dividend->getType()->getIntegerBitWidth();
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Shift = Builder.getInt64(63);
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assert(BitWidth == 32 && "Unexpected bit width");
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Shift = Builder.getInt32(31);
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// Following instructions are generated for both i32 (shift 31) and
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// ; %dividend_sgn = ashr i32 %dividend, 31
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// ; %divisor_sgn = ashr i32 %divisor, 31
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// ; %dvd_xor = xor i32 %dividend, %dividend_sgn
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// ; %dvs_xor = xor i32 %divisor, %divisor_sgn
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// ; %u_dividend = sub i32 %dvd_xor, %dividend_sgn
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// ; %u_divisor = sub i32 %dvs_xor, %divisor_sgn
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// ; %urem = urem i32 %dividend, %divisor
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// ; %xored = xor i32 %urem, %dividend_sgn
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// ; %srem = sub i32 %xored, %dividend_sgn
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Value *DividendSign = Builder.CreateAShr(Dividend, Shift);
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Value *DivisorSign = Builder.CreateAShr(Divisor, Shift);
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Value *DvdXor = Builder.CreateXor(Dividend, DividendSign);
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Value *DvsXor = Builder.CreateXor(Divisor, DivisorSign);
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Value *UDividend = Builder.CreateSub(DvdXor, DividendSign);
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Value *UDivisor = Builder.CreateSub(DvsXor, DivisorSign);
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Value *URem = Builder.CreateURem(UDividend, UDivisor);
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Value *Xored = Builder.CreateXor(URem, DividendSign);
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Value *SRem = Builder.CreateSub(Xored, DividendSign);
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if (Instruction *URemInst = dyn_cast<Instruction>(URem))
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Builder.SetInsertPoint(URemInst);
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/// Generate code to compute the remainder of two unsigned integers. Returns the
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/// remainder. Builder's insert point should be pointing where the caller wants
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/// code generated, e.g. at the urem instruction. This will generate a udiv in
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/// the process, and Builder's insert point will be pointing at the udiv (if
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/// present, i.e. not folded), ready to be expanded if the user wishes
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static Value *generatedUnsignedRemainderCode(Value *Dividend, Value *Divisor,
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IRBuilder<> &Builder) {
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// Remainder = Dividend - Quotient*Divisor
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// Following instructions are generated for both i32 and i64
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// ; %quotient = udiv i32 %dividend, %divisor
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// ; %product = mul i32 %divisor, %quotient
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// ; %remainder = sub i32 %dividend, %product
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Value *Quotient = Builder.CreateUDiv(Dividend, Divisor);
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Value *Product = Builder.CreateMul(Divisor, Quotient);
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Value *Remainder = Builder.CreateSub(Dividend, Product);
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if (Instruction *UDiv = dyn_cast<Instruction>(Quotient))
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Builder.SetInsertPoint(UDiv);
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/// Generate code to divide two signed integers. Returns the quotient, rounded
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/// towards 0. Builder's insert point should be pointing where the caller wants
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/// code generated, e.g. at the sdiv instruction. This will generate a udiv in
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/// the process, and Builder's insert point will be pointing at the udiv (if
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/// present, i.e. not folded), ready to be expanded if the user wishes.
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static Value *generateSignedDivisionCode(Value *Dividend, Value *Divisor,
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IRBuilder<> &Builder) {
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// Implementation taken from compiler-rt's __divsi3 and __divdi3
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unsigned BitWidth = Dividend->getType()->getIntegerBitWidth();
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if (BitWidth == 64) {
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Shift = Builder.getInt64(63);
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assert(BitWidth == 32 && "Unexpected bit width");
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Shift = Builder.getInt32(31);
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// Following instructions are generated for both i32 (shift 31) and
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// ; %tmp = ashr i32 %dividend, 31
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// ; %tmp1 = ashr i32 %divisor, 31
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// ; %tmp2 = xor i32 %tmp, %dividend
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// ; %u_dvnd = sub nsw i32 %tmp2, %tmp
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// ; %tmp3 = xor i32 %tmp1, %divisor
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// ; %u_dvsr = sub nsw i32 %tmp3, %tmp1
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// ; %q_sgn = xor i32 %tmp1, %tmp
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// ; %q_mag = udiv i32 %u_dvnd, %u_dvsr
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// ; %tmp4 = xor i32 %q_mag, %q_sgn
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// ; %q = sub i32 %tmp4, %q_sgn
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Value *Tmp = Builder.CreateAShr(Dividend, Shift);
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Value *Tmp1 = Builder.CreateAShr(Divisor, Shift);
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Value *Tmp2 = Builder.CreateXor(Tmp, Dividend);
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Value *U_Dvnd = Builder.CreateSub(Tmp2, Tmp);
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Value *Tmp3 = Builder.CreateXor(Tmp1, Divisor);
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Value *U_Dvsr = Builder.CreateSub(Tmp3, Tmp1);
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Value *Q_Sgn = Builder.CreateXor(Tmp1, Tmp);
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Value *Q_Mag = Builder.CreateUDiv(U_Dvnd, U_Dvsr);
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Value *Tmp4 = Builder.CreateXor(Q_Mag, Q_Sgn);
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Value *Q = Builder.CreateSub(Tmp4, Q_Sgn);
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if (Instruction *UDiv = dyn_cast<Instruction>(Q_Mag))
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Builder.SetInsertPoint(UDiv);
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/// Generates code to divide two unsigned scalar 32-bit or 64-bit integers.
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/// Returns the quotient, rounded towards 0. Builder's insert point should
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/// point where the caller wants code generated, e.g. at the udiv instruction.
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static Value *generateUnsignedDivisionCode(Value *Dividend, Value *Divisor,
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IRBuilder<> &Builder) {
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// The basic algorithm can be found in the compiler-rt project's
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// implementation of __udivsi3.c. Here, we do a lower-level IR based approach
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// that's been hand-tuned to lessen the amount of control flow involved.
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// Some helper values
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IntegerType *DivTy = cast<IntegerType>(Dividend->getType());
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unsigned BitWidth = DivTy->getBitWidth();
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if (BitWidth == 64) {
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Zero = Builder.getInt64(0);
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One = Builder.getInt64(1);
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NegOne = ConstantInt::getSigned(DivTy, -1);
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MSB = Builder.getInt64(63);
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assert(BitWidth == 32 && "Unexpected bit width");
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Zero = Builder.getInt32(0);
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One = Builder.getInt32(1);
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NegOne = ConstantInt::getSigned(DivTy, -1);
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MSB = Builder.getInt32(31);
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ConstantInt *True = Builder.getTrue();
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BasicBlock *IBB = Builder.GetInsertBlock();
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Function *F = IBB->getParent();
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Function *CTLZ = Intrinsic::getDeclaration(F->getParent(), Intrinsic::ctlz,
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// Our CFG is going to look like:
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// +---------------------+
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// +---------------------+
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// | | +------------+
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// | | +------------+
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// | | +------------+ |
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// | | | do-while | |
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// | | +------------+ |
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// | +-----------+ +---+
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BasicBlock *SpecialCases = Builder.GetInsertBlock();
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SpecialCases->setName(Twine(SpecialCases->getName(), "_udiv-special-cases"));
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BasicBlock *End = SpecialCases->splitBasicBlock(Builder.GetInsertPoint(),
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BasicBlock *LoopExit = BasicBlock::Create(Builder.getContext(),
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"udiv-loop-exit", F, End);
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BasicBlock *DoWhile = BasicBlock::Create(Builder.getContext(),
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"udiv-do-while", F, End);
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BasicBlock *Preheader = BasicBlock::Create(Builder.getContext(),
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"udiv-preheader", F, End);
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BasicBlock *BB1 = BasicBlock::Create(Builder.getContext(),
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// We'll be overwriting the terminator to insert our extra blocks
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SpecialCases->getTerminator()->eraseFromParent();
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// Same instructions are generated for both i32 (msb 31) and i64 (msb 63).
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// First off, check for special cases: dividend or divisor is zero, divisor
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// is greater than dividend, and divisor is 1.
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// ; %ret0_1 = icmp eq i32 %divisor, 0
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// ; %ret0_2 = icmp eq i32 %dividend, 0
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// ; %ret0_3 = or i1 %ret0_1, %ret0_2
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// ; %tmp0 = tail call i32 @llvm.ctlz.i32(i32 %divisor, i1 true)
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// ; %tmp1 = tail call i32 @llvm.ctlz.i32(i32 %dividend, i1 true)
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// ; %sr = sub nsw i32 %tmp0, %tmp1
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// ; %ret0_4 = icmp ugt i32 %sr, 31
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// ; %ret0 = or i1 %ret0_3, %ret0_4
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// ; %retDividend = icmp eq i32 %sr, 31
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// ; %retVal = select i1 %ret0, i32 0, i32 %dividend
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// ; %earlyRet = or i1 %ret0, %retDividend
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// ; br i1 %earlyRet, label %end, label %bb1
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Builder.SetInsertPoint(SpecialCases);
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Value *Ret0_1 = Builder.CreateICmpEQ(Divisor, Zero);
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Value *Ret0_2 = Builder.CreateICmpEQ(Dividend, Zero);
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Value *Ret0_3 = Builder.CreateOr(Ret0_1, Ret0_2);
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Value *Tmp0 = Builder.CreateCall(CTLZ, {Divisor, True});
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Value *Tmp1 = Builder.CreateCall(CTLZ, {Dividend, True});
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Value *SR = Builder.CreateSub(Tmp0, Tmp1);
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Value *Ret0_4 = Builder.CreateICmpUGT(SR, MSB);
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Value *Ret0 = Builder.CreateOr(Ret0_3, Ret0_4);
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Value *RetDividend = Builder.CreateICmpEQ(SR, MSB);
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Value *RetVal = Builder.CreateSelect(Ret0, Zero, Dividend);
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Value *EarlyRet = Builder.CreateOr(Ret0, RetDividend);
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Builder.CreateCondBr(EarlyRet, End, BB1);
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// ; bb1: ; preds = %special-cases
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// ; %sr_1 = add i32 %sr, 1
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// ; %tmp2 = sub i32 31, %sr
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// ; %q = shl i32 %dividend, %tmp2
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// ; %skipLoop = icmp eq i32 %sr_1, 0
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// ; br i1 %skipLoop, label %loop-exit, label %preheader
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Builder.SetInsertPoint(BB1);
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Value *SR_1 = Builder.CreateAdd(SR, One);
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Value *Tmp2 = Builder.CreateSub(MSB, SR);
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Value *Q = Builder.CreateShl(Dividend, Tmp2);
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Value *SkipLoop = Builder.CreateICmpEQ(SR_1, Zero);
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Builder.CreateCondBr(SkipLoop, LoopExit, Preheader);
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// ; preheader: ; preds = %bb1
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// ; %tmp3 = lshr i32 %dividend, %sr_1
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// ; %tmp4 = add i32 %divisor, -1
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// ; br label %do-while
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Builder.SetInsertPoint(Preheader);
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Value *Tmp3 = Builder.CreateLShr(Dividend, SR_1);
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Value *Tmp4 = Builder.CreateAdd(Divisor, NegOne);
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Builder.CreateBr(DoWhile);
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// ; do-while: ; preds = %do-while, %preheader
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// ; %carry_1 = phi i32 [ 0, %preheader ], [ %carry, %do-while ]
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// ; %sr_3 = phi i32 [ %sr_1, %preheader ], [ %sr_2, %do-while ]
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// ; %r_1 = phi i32 [ %tmp3, %preheader ], [ %r, %do-while ]
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// ; %q_2 = phi i32 [ %q, %preheader ], [ %q_1, %do-while ]
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// ; %tmp5 = shl i32 %r_1, 1
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// ; %tmp6 = lshr i32 %q_2, 31
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// ; %tmp7 = or i32 %tmp5, %tmp6
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// ; %tmp8 = shl i32 %q_2, 1
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// ; %q_1 = or i32 %carry_1, %tmp8
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// ; %tmp9 = sub i32 %tmp4, %tmp7
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// ; %tmp10 = ashr i32 %tmp9, 31
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// ; %carry = and i32 %tmp10, 1
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// ; %tmp11 = and i32 %tmp10, %divisor
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// ; %r = sub i32 %tmp7, %tmp11
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// ; %sr_2 = add i32 %sr_3, -1
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// ; %tmp12 = icmp eq i32 %sr_2, 0
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// ; br i1 %tmp12, label %loop-exit, label %do-while
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Builder.SetInsertPoint(DoWhile);
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PHINode *Carry_1 = Builder.CreatePHI(DivTy, 2);
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PHINode *SR_3 = Builder.CreatePHI(DivTy, 2);
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PHINode *R_1 = Builder.CreatePHI(DivTy, 2);
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PHINode *Q_2 = Builder.CreatePHI(DivTy, 2);
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Value *Tmp5 = Builder.CreateShl(R_1, One);
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Value *Tmp6 = Builder.CreateLShr(Q_2, MSB);
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Value *Tmp7 = Builder.CreateOr(Tmp5, Tmp6);
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Value *Tmp8 = Builder.CreateShl(Q_2, One);
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Value *Q_1 = Builder.CreateOr(Carry_1, Tmp8);
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Value *Tmp9 = Builder.CreateSub(Tmp4, Tmp7);
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Value *Tmp10 = Builder.CreateAShr(Tmp9, MSB);
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Value *Carry = Builder.CreateAnd(Tmp10, One);
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Value *Tmp11 = Builder.CreateAnd(Tmp10, Divisor);
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Value *R = Builder.CreateSub(Tmp7, Tmp11);
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Value *SR_2 = Builder.CreateAdd(SR_3, NegOne);
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Value *Tmp12 = Builder.CreateICmpEQ(SR_2, Zero);
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Builder.CreateCondBr(Tmp12, LoopExit, DoWhile);
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// ; loop-exit: ; preds = %do-while, %bb1
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// ; %carry_2 = phi i32 [ 0, %bb1 ], [ %carry, %do-while ]
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// ; %q_3 = phi i32 [ %q, %bb1 ], [ %q_1, %do-while ]
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// ; %tmp13 = shl i32 %q_3, 1
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// ; %q_4 = or i32 %carry_2, %tmp13
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Builder.SetInsertPoint(LoopExit);
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PHINode *Carry_2 = Builder.CreatePHI(DivTy, 2);
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PHINode *Q_3 = Builder.CreatePHI(DivTy, 2);
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Value *Tmp13 = Builder.CreateShl(Q_3, One);
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Value *Q_4 = Builder.CreateOr(Carry_2, Tmp13);
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Builder.CreateBr(End);
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// ; end: ; preds = %loop-exit, %special-cases
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// ; %q_5 = phi i32 [ %q_4, %loop-exit ], [ %retVal, %special-cases ]
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Builder.SetInsertPoint(End, End->begin());
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PHINode *Q_5 = Builder.CreatePHI(DivTy, 2);
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// Populate the Phis, since all values have now been created. Our Phis were:
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// ; %carry_1 = phi i32 [ 0, %preheader ], [ %carry, %do-while ]
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Carry_1->addIncoming(Zero, Preheader);
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Carry_1->addIncoming(Carry, DoWhile);
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// ; %sr_3 = phi i32 [ %sr_1, %preheader ], [ %sr_2, %do-while ]
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SR_3->addIncoming(SR_1, Preheader);
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SR_3->addIncoming(SR_2, DoWhile);
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// ; %r_1 = phi i32 [ %tmp3, %preheader ], [ %r, %do-while ]
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R_1->addIncoming(Tmp3, Preheader);
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R_1->addIncoming(R, DoWhile);
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// ; %q_2 = phi i32 [ %q, %preheader ], [ %q_1, %do-while ]
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Q_2->addIncoming(Q, Preheader);
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Q_2->addIncoming(Q_1, DoWhile);
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// ; %carry_2 = phi i32 [ 0, %bb1 ], [ %carry, %do-while ]
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Carry_2->addIncoming(Zero, BB1);
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Carry_2->addIncoming(Carry, DoWhile);
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// ; %q_3 = phi i32 [ %q, %bb1 ], [ %q_1, %do-while ]
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Q_3->addIncoming(Q, BB1);
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Q_3->addIncoming(Q_1, DoWhile);
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// ; %q_5 = phi i32 [ %q_4, %loop-exit ], [ %retVal, %special-cases ]
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Q_5->addIncoming(Q_4, LoopExit);
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Q_5->addIncoming(RetVal, SpecialCases);
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/// Generate code to calculate the remainder of two integers, replacing Rem with
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/// the generated code. This currently generates code using the udiv expansion,
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/// but future work includes generating more specialized code, e.g. when more
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/// information about the operands are known. Implements both 32bit and 64bit
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/// @brief Replace Rem with generated code.
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bool llvm::expandRemainder(BinaryOperator *Rem) {
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assert((Rem->getOpcode() == Instruction::SRem ||
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Rem->getOpcode() == Instruction::URem) &&
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"Trying to expand remainder from a non-remainder function");
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IRBuilder<> Builder(Rem);
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Type *RemTy = Rem->getType();
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if (RemTy->isVectorTy())
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llvm_unreachable("Div over vectors not supported");
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unsigned RemTyBitWidth = RemTy->getIntegerBitWidth();
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if (RemTyBitWidth != 32 && RemTyBitWidth != 64)
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llvm_unreachable("Div of bitwidth other than 32 or 64 not supported");
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// First prepare the sign if it's a signed remainder
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if (Rem->getOpcode() == Instruction::SRem) {
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Value *Remainder = generateSignedRemainderCode(Rem->getOperand(0),
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Rem->getOperand(1), Builder);
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Rem->replaceAllUsesWith(Remainder);
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Rem->dropAllReferences();
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Rem->eraseFromParent();
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// If we didn't actually generate an urem instruction, we're done
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// This happens for example if the input were constant. In this case the
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// Builder insertion point was unchanged
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if (Rem == Builder.GetInsertPoint())
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BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
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Value *Remainder = generatedUnsignedRemainderCode(Rem->getOperand(0),
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Rem->replaceAllUsesWith(Remainder);
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Rem->dropAllReferences();
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Rem->eraseFromParent();
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if (BinaryOperator *UDiv = dyn_cast<BinaryOperator>(Builder.GetInsertPoint())) {
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assert(UDiv->getOpcode() == Instruction::UDiv && "Non-udiv in expansion?");
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expandDivision(UDiv);
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/// Generate code to divide two integers, replacing Div with the generated
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/// code. This currently generates code similarly to compiler-rt's
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/// implementations, but future work includes generating more specialized code
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/// when more information about the operands are known. Implements both
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/// 32bit and 64bit scalar division.
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/// @brief Replace Div with generated code.
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bool llvm::expandDivision(BinaryOperator *Div) {
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assert((Div->getOpcode() == Instruction::SDiv ||
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Div->getOpcode() == Instruction::UDiv) &&
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"Trying to expand division from a non-division function");
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IRBuilder<> Builder(Div);
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Type *DivTy = Div->getType();
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if (DivTy->isVectorTy())
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llvm_unreachable("Div over vectors not supported");
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unsigned DivTyBitWidth = DivTy->getIntegerBitWidth();
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if (DivTyBitWidth != 32 && DivTyBitWidth != 64)
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llvm_unreachable("Div of bitwidth other than 32 or 64 not supported");
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// First prepare the sign if it's a signed division
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if (Div->getOpcode() == Instruction::SDiv) {
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// Lower the code to unsigned division, and reset Div to point to the udiv.
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Value *Quotient = generateSignedDivisionCode(Div->getOperand(0),
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Div->getOperand(1), Builder);
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Div->replaceAllUsesWith(Quotient);
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Div->dropAllReferences();
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Div->eraseFromParent();
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// If we didn't actually generate an udiv instruction, we're done
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// This happens for example if the input were constant. In this case the
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// Builder insertion point was unchanged
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if (Div == Builder.GetInsertPoint())
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BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
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// Insert the unsigned division code
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Value *Quotient = generateUnsignedDivisionCode(Div->getOperand(0),
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Div->replaceAllUsesWith(Quotient);
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Div->dropAllReferences();
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Div->eraseFromParent();
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/// Generate code to compute the remainder of two integers of bitwidth up to
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/// 32 bits. Uses the above routines and extends the inputs/truncates the
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/// outputs to operate in 32 bits; that is, these routines are good for targets
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/// that have no or very little suppport for smaller than 32 bit integer
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/// @brief Replace Rem with emulation code.
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bool llvm::expandRemainderUpTo32Bits(BinaryOperator *Rem) {
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assert((Rem->getOpcode() == Instruction::SRem ||
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Rem->getOpcode() == Instruction::URem) &&
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"Trying to expand remainder from a non-remainder function");
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Type *RemTy = Rem->getType();
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if (RemTy->isVectorTy())
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llvm_unreachable("Div over vectors not supported");
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unsigned RemTyBitWidth = RemTy->getIntegerBitWidth();
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if (RemTyBitWidth > 32)
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llvm_unreachable("Div of bitwidth greater than 32 not supported");
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if (RemTyBitWidth == 32)
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return expandRemainder(Rem);
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// If bitwidth smaller than 32 extend inputs, extend output and proceed
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// with 32 bit division.
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IRBuilder<> Builder(Rem);
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Type *Int32Ty = Builder.getInt32Ty();
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if (Rem->getOpcode() == Instruction::SRem) {
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ExtDividend = Builder.CreateSExt(Rem->getOperand(0), Int32Ty);
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ExtDivisor = Builder.CreateSExt(Rem->getOperand(1), Int32Ty);
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ExtRem = Builder.CreateSRem(ExtDividend, ExtDivisor);
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ExtDividend = Builder.CreateZExt(Rem->getOperand(0), Int32Ty);
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ExtDivisor = Builder.CreateZExt(Rem->getOperand(1), Int32Ty);
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ExtRem = Builder.CreateURem(ExtDividend, ExtDivisor);
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Trunc = Builder.CreateTrunc(ExtRem, RemTy);
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Rem->replaceAllUsesWith(Trunc);
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Rem->dropAllReferences();
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Rem->eraseFromParent();
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return expandRemainder(cast<BinaryOperator>(ExtRem));
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/// Generate code to compute the remainder of two integers of bitwidth up to
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/// 64 bits. Uses the above routines and extends the inputs/truncates the
536
/// outputs to operate in 64 bits.
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/// @brief Replace Rem with emulation code.
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bool llvm::expandRemainderUpTo64Bits(BinaryOperator *Rem) {
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assert((Rem->getOpcode() == Instruction::SRem ||
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Rem->getOpcode() == Instruction::URem) &&
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"Trying to expand remainder from a non-remainder function");
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Type *RemTy = Rem->getType();
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if (RemTy->isVectorTy())
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llvm_unreachable("Div over vectors not supported");
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unsigned RemTyBitWidth = RemTy->getIntegerBitWidth();
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if (RemTyBitWidth > 64)
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llvm_unreachable("Div of bitwidth greater than 64 not supported");
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if (RemTyBitWidth == 64)
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return expandRemainder(Rem);
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// If bitwidth smaller than 64 extend inputs, extend output and proceed
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// with 64 bit division.
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IRBuilder<> Builder(Rem);
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Type *Int64Ty = Builder.getInt64Ty();
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if (Rem->getOpcode() == Instruction::SRem) {
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ExtDividend = Builder.CreateSExt(Rem->getOperand(0), Int64Ty);
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ExtDivisor = Builder.CreateSExt(Rem->getOperand(1), Int64Ty);
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ExtRem = Builder.CreateSRem(ExtDividend, ExtDivisor);
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ExtDividend = Builder.CreateZExt(Rem->getOperand(0), Int64Ty);
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ExtDivisor = Builder.CreateZExt(Rem->getOperand(1), Int64Ty);
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ExtRem = Builder.CreateURem(ExtDividend, ExtDivisor);
575
Trunc = Builder.CreateTrunc(ExtRem, RemTy);
577
Rem->replaceAllUsesWith(Trunc);
578
Rem->dropAllReferences();
579
Rem->eraseFromParent();
581
return expandRemainder(cast<BinaryOperator>(ExtRem));
584
/// Generate code to divide two integers of bitwidth up to 32 bits. Uses the
585
/// above routines and extends the inputs/truncates the outputs to operate
586
/// in 32 bits; that is, these routines are good for targets that have no
587
/// or very little support for smaller than 32 bit integer arithmetic.
589
/// @brief Replace Div with emulation code.
590
bool llvm::expandDivisionUpTo32Bits(BinaryOperator *Div) {
591
assert((Div->getOpcode() == Instruction::SDiv ||
592
Div->getOpcode() == Instruction::UDiv) &&
593
"Trying to expand division from a non-division function");
595
Type *DivTy = Div->getType();
596
if (DivTy->isVectorTy())
597
llvm_unreachable("Div over vectors not supported");
599
unsigned DivTyBitWidth = DivTy->getIntegerBitWidth();
601
if (DivTyBitWidth > 32)
602
llvm_unreachable("Div of bitwidth greater than 32 not supported");
604
if (DivTyBitWidth == 32)
605
return expandDivision(Div);
607
// If bitwidth smaller than 32 extend inputs, extend output and proceed
608
// with 32 bit division.
609
IRBuilder<> Builder(Div);
615
Type *Int32Ty = Builder.getInt32Ty();
617
if (Div->getOpcode() == Instruction::SDiv) {
618
ExtDividend = Builder.CreateSExt(Div->getOperand(0), Int32Ty);
619
ExtDivisor = Builder.CreateSExt(Div->getOperand(1), Int32Ty);
620
ExtDiv = Builder.CreateSDiv(ExtDividend, ExtDivisor);
622
ExtDividend = Builder.CreateZExt(Div->getOperand(0), Int32Ty);
623
ExtDivisor = Builder.CreateZExt(Div->getOperand(1), Int32Ty);
624
ExtDiv = Builder.CreateUDiv(ExtDividend, ExtDivisor);
626
Trunc = Builder.CreateTrunc(ExtDiv, DivTy);
628
Div->replaceAllUsesWith(Trunc);
629
Div->dropAllReferences();
630
Div->eraseFromParent();
632
return expandDivision(cast<BinaryOperator>(ExtDiv));
635
/// Generate code to divide two integers of bitwidth up to 64 bits. Uses the
636
/// above routines and extends the inputs/truncates the outputs to operate
639
/// @brief Replace Div with emulation code.
640
bool llvm::expandDivisionUpTo64Bits(BinaryOperator *Div) {
641
assert((Div->getOpcode() == Instruction::SDiv ||
642
Div->getOpcode() == Instruction::UDiv) &&
643
"Trying to expand division from a non-division function");
645
Type *DivTy = Div->getType();
646
if (DivTy->isVectorTy())
647
llvm_unreachable("Div over vectors not supported");
649
unsigned DivTyBitWidth = DivTy->getIntegerBitWidth();
651
if (DivTyBitWidth > 64)
652
llvm_unreachable("Div of bitwidth greater than 64 not supported");
654
if (DivTyBitWidth == 64)
655
return expandDivision(Div);
657
// If bitwidth smaller than 64 extend inputs, extend output and proceed
658
// with 64 bit division.
659
IRBuilder<> Builder(Div);
665
Type *Int64Ty = Builder.getInt64Ty();
667
if (Div->getOpcode() == Instruction::SDiv) {
668
ExtDividend = Builder.CreateSExt(Div->getOperand(0), Int64Ty);
669
ExtDivisor = Builder.CreateSExt(Div->getOperand(1), Int64Ty);
670
ExtDiv = Builder.CreateSDiv(ExtDividend, ExtDivisor);
672
ExtDividend = Builder.CreateZExt(Div->getOperand(0), Int64Ty);
673
ExtDivisor = Builder.CreateZExt(Div->getOperand(1), Int64Ty);
674
ExtDiv = Builder.CreateUDiv(ExtDividend, ExtDivisor);
676
Trunc = Builder.CreateTrunc(ExtDiv, DivTy);
678
Div->replaceAllUsesWith(Trunc);
679
Div->dropAllReferences();
680
Div->eraseFromParent();
682
return expandDivision(cast<BinaryOperator>(ExtDiv));