2010-01-05 06:09:35 +00:00
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//===- InstCombineMulDivRem.cpp -------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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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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//===----------------------------------------------------------------------===//
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//
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// This file implements the visit functions for mul, fmul, sdiv, udiv, fdiv,
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// srem, urem, frem.
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//
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//===----------------------------------------------------------------------===//
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#include "InstCombine.h"
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2010-12-21 14:00:22 +00:00
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#include "llvm/Analysis/InstructionSimplify.h"
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2013-01-02 11:36:10 +00:00
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#include "llvm/IR/IntrinsicInst.h"
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2010-01-05 06:09:35 +00:00
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#include "llvm/Support/PatternMatch.h"
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using namespace llvm;
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using namespace PatternMatch;
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Carve out a place in instcombine to put transformations which work knowing that their
result is non-zero. Implement an example optimization (PR9814), which allows us to
transform:
A / ((1 << B) >>u 2)
into:
A >>u (B-2)
which we compile into:
_divu3: ## @divu3
leal -2(%rsi), %ecx
shrl %cl, %edi
movl %edi, %eax
ret
instead of:
_divu3: ## @divu3
movb %sil, %cl
movl $1, %esi
shll %cl, %esi
shrl $2, %esi
movl %edi, %eax
xorl %edx, %edx
divl %esi, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131860 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22 18:18:41 +00:00
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/// simplifyValueKnownNonZero - The specific integer value is used in a context
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/// where it is known to be non-zero. If this allows us to simplify the
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/// computation, do so and return the new operand, otherwise return null.
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static Value *simplifyValueKnownNonZero(Value *V, InstCombiner &IC) {
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// If V has multiple uses, then we would have to do more analysis to determine
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// if this is safe. For example, the use could be in dynamically unreached
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// code.
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if (!V->hasOneUse()) return 0;
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2013-04-05 21:20:12 +00:00
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2011-05-23 00:32:19 +00:00
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bool MadeChange = false;
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// ((1 << A) >>u B) --> (1 << (A-B))
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// Because V cannot be zero, we know that B is less than A.
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Value *A = 0, *B = 0, *PowerOf2 = 0;
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if (match(V, m_LShr(m_OneUse(m_Shl(m_Value(PowerOf2), m_Value(A))),
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m_Value(B))) &&
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// The "1" can be any value known to be a power of 2.
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2012-12-13 03:37:24 +00:00
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isKnownToBeAPowerOfTwo(PowerOf2)) {
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2011-09-27 20:39:19 +00:00
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A = IC.Builder->CreateSub(A, B);
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2011-05-23 00:32:19 +00:00
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return IC.Builder->CreateShl(PowerOf2, A);
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}
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2013-04-05 21:20:12 +00:00
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2011-05-23 00:21:50 +00:00
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// (PowerOfTwo >>u B) --> isExact since shifting out the result would make it
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// inexact. Similarly for <<.
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if (BinaryOperator *I = dyn_cast<BinaryOperator>(V))
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2012-12-13 03:37:24 +00:00
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if (I->isLogicalShift() && isKnownToBeAPowerOfTwo(I->getOperand(0))) {
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2011-05-23 00:32:19 +00:00
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// We know that this is an exact/nuw shift and that the input is a
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// non-zero context as well.
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if (Value *V2 = simplifyValueKnownNonZero(I->getOperand(0), IC)) {
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I->setOperand(0, V2);
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MadeChange = true;
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}
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2013-04-05 21:20:12 +00:00
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2011-05-23 00:21:50 +00:00
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if (I->getOpcode() == Instruction::LShr && !I->isExact()) {
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I->setIsExact();
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2011-05-23 00:32:19 +00:00
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MadeChange = true;
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2011-05-23 00:21:50 +00:00
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}
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2013-04-05 21:20:12 +00:00
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2011-05-23 00:21:50 +00:00
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if (I->getOpcode() == Instruction::Shl && !I->hasNoUnsignedWrap()) {
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I->setHasNoUnsignedWrap();
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2011-05-23 00:32:19 +00:00
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MadeChange = true;
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2011-05-23 00:21:50 +00:00
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}
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}
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2011-05-23 00:32:19 +00:00
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2011-05-22 18:26:48 +00:00
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// TODO: Lots more we could do here:
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// If V is a phi node, we can call this on each of its operands.
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// "select cond, X, 0" can simplify to "X".
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2013-04-05 21:20:12 +00:00
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2011-05-23 00:32:19 +00:00
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return MadeChange ? V : 0;
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Carve out a place in instcombine to put transformations which work knowing that their
result is non-zero. Implement an example optimization (PR9814), which allows us to
transform:
A / ((1 << B) >>u 2)
into:
A >>u (B-2)
which we compile into:
_divu3: ## @divu3
leal -2(%rsi), %ecx
shrl %cl, %edi
movl %edi, %eax
ret
instead of:
_divu3: ## @divu3
movb %sil, %cl
movl $1, %esi
shll %cl, %esi
shrl $2, %esi
movl %edi, %eax
xorl %edx, %edx
divl %esi, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131860 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22 18:18:41 +00:00
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}
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2010-01-05 06:09:35 +00:00
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/// MultiplyOverflows - True if the multiply can not be expressed in an int
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/// this size.
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static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
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uint32_t W = C1->getBitWidth();
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APInt LHSExt = C1->getValue(), RHSExt = C2->getValue();
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if (sign) {
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2010-12-07 08:25:19 +00:00
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LHSExt = LHSExt.sext(W * 2);
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RHSExt = RHSExt.sext(W * 2);
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2010-01-05 06:09:35 +00:00
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} else {
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2010-12-07 08:25:19 +00:00
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LHSExt = LHSExt.zext(W * 2);
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RHSExt = RHSExt.zext(W * 2);
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2010-01-05 06:09:35 +00:00
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}
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2013-04-05 21:20:12 +00:00
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2010-01-05 06:09:35 +00:00
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APInt MulExt = LHSExt * RHSExt;
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2013-04-05 21:20:12 +00:00
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2010-01-05 06:09:35 +00:00
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if (!sign)
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return MulExt.ugt(APInt::getLowBitsSet(W * 2, W));
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2013-04-05 21:20:12 +00:00
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2010-01-05 06:09:35 +00:00
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APInt Min = APInt::getSignedMinValue(W).sext(W * 2);
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APInt Max = APInt::getSignedMaxValue(W).sext(W * 2);
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return MulExt.slt(Min) || MulExt.sgt(Max);
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}
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2013-05-31 14:27:15 +00:00
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/// \brief A helper routine of InstCombiner::visitMul().
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///
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/// If C is a vector of known powers of 2, then this function returns
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/// a new vector obtained from C replacing each element with its logBase2.
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/// Return a null pointer otherwise.
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static Constant *getLogBase2Vector(ConstantDataVector *CV) {
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const APInt *IVal;
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SmallVector<Constant *, 4> Elts;
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for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
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Constant *Elt = CV->getElementAsConstant(I);
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if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2())
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return 0;
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Elts.push_back(ConstantInt::get(Elt->getType(), IVal->logBase2()));
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}
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return ConstantVector::get(Elts);
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}
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2010-01-05 06:09:35 +00:00
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Instruction *InstCombiner::visitMul(BinaryOperator &I) {
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2010-11-13 15:10:37 +00:00
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bool Changed = SimplifyAssociativeOrCommutative(I);
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2010-01-05 06:09:35 +00:00
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Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
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2010-12-21 14:00:22 +00:00
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if (Value *V = SimplifyMulInst(Op0, Op1, TD))
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return ReplaceInstUsesWith(I, V);
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2010-01-05 06:09:35 +00:00
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2010-12-22 13:36:08 +00:00
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if (Value *V = SimplifyUsingDistributiveLaws(I))
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return ReplaceInstUsesWith(I, V);
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2011-02-10 05:36:31 +00:00
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if (match(Op1, m_AllOnes())) // X * -1 == 0 - X
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return BinaryOperator::CreateNeg(Op0, I.getName());
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2013-04-05 21:20:12 +00:00
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2013-05-31 14:27:15 +00:00
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// Also allow combining multiply instructions on vectors.
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{
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Value *NewOp;
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Constant *C1, *C2;
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const APInt *IVal;
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if (match(&I, m_Mul(m_Shl(m_Value(NewOp), m_Constant(C2)),
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m_Constant(C1))) &&
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match(C1, m_APInt(IVal)))
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// ((X << C1)*C2) == (X * (C2 << C1))
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return BinaryOperator::CreateMul(NewOp, ConstantExpr::getShl(C1, C2));
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if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) {
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Constant *NewCst = 0;
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if (match(C1, m_APInt(IVal)) && IVal->isPowerOf2())
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// Replace X*(2^C) with X << C, where C is either a scalar or a splat.
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NewCst = ConstantInt::get(NewOp->getType(), IVal->logBase2());
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else if (ConstantDataVector *CV = dyn_cast<ConstantDataVector>(C1))
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// Replace X*(2^C) with X << C, where C is a vector of known
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// constant powers of 2.
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NewCst = getLogBase2Vector(CV);
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if (NewCst) {
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BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
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if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
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if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
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return Shl;
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}
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2010-01-05 06:09:35 +00:00
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}
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2013-05-31 14:27:15 +00:00
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}
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2013-04-05 21:20:12 +00:00
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2013-05-31 14:27:15 +00:00
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if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
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2011-02-10 05:36:31 +00:00
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// Canonicalize (X+C1)*CI -> X*CI+C1*CI.
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{ Value *X; ConstantInt *C1;
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if (Op0->hasOneUse() &&
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match(Op0, m_Add(m_Value(X), m_ConstantInt(C1)))) {
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2011-09-27 20:39:19 +00:00
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Value *Add = Builder->CreateMul(X, CI);
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2011-02-10 05:36:31 +00:00
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return BinaryOperator::CreateAdd(Add, Builder->CreateMul(C1, CI));
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2010-01-05 06:09:35 +00:00
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}
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2011-02-10 05:36:31 +00:00
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}
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2011-05-30 20:00:33 +00:00
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2011-06-01 16:42:47 +00:00
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// (Y - X) * (-(2**n)) -> (X - Y) * (2**n), for positive nonzero n
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// (Y + const) * (-(2**n)) -> (-constY) * (2**n), for positive nonzero n
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// The "* (2**n)" thus becomes a potential shifting opportunity.
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2011-05-30 20:00:33 +00:00
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{
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const APInt & Val = CI->getValue();
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const APInt &PosVal = Val.abs();
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if (Val.isNegative() && PosVal.isPowerOf2()) {
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2011-06-01 16:42:47 +00:00
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Value *X = 0, *Y = 0;
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if (Op0->hasOneUse()) {
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ConstantInt *C1;
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Value *Sub = 0;
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if (match(Op0, m_Sub(m_Value(Y), m_Value(X))))
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Sub = Builder->CreateSub(X, Y, "suba");
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else if (match(Op0, m_Add(m_Value(Y), m_ConstantInt(C1))))
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Sub = Builder->CreateSub(Builder->CreateNeg(C1), Y, "subc");
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if (Sub)
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return
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BinaryOperator::CreateMul(Sub,
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ConstantInt::get(Y->getType(), PosVal));
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2011-05-30 20:00:33 +00:00
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}
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}
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}
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2011-02-10 05:36:31 +00:00
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}
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2013-04-05 21:20:12 +00:00
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2011-02-10 05:36:31 +00:00
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// Simplify mul instructions with a constant RHS.
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2013-04-05 21:20:12 +00:00
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if (isa<Constant>(Op1)) {
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2010-01-05 06:09:35 +00:00
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// Try to fold constant mul into select arguments.
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if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
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if (Instruction *R = FoldOpIntoSelect(I, SI))
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return R;
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if (isa<PHINode>(Op0))
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if (Instruction *NV = FoldOpIntoPhi(I))
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return NV;
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}
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if (Value *Op0v = dyn_castNegVal(Op0)) // -X * -Y = X*Y
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if (Value *Op1v = dyn_castNegVal(Op1))
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return BinaryOperator::CreateMul(Op0v, Op1v);
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// (X / Y) * Y = X - (X % Y)
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// (X / Y) * -Y = (X % Y) - X
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{
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Value *Op1C = Op1;
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BinaryOperator *BO = dyn_cast<BinaryOperator>(Op0);
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if (!BO ||
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2013-04-05 21:20:12 +00:00
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(BO->getOpcode() != Instruction::UDiv &&
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2010-01-05 06:09:35 +00:00
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BO->getOpcode() != Instruction::SDiv)) {
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Op1C = Op0;
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BO = dyn_cast<BinaryOperator>(Op1);
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}
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Value *Neg = dyn_castNegVal(Op1C);
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if (BO && BO->hasOneUse() &&
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(BO->getOperand(1) == Op1C || BO->getOperand(1) == Neg) &&
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(BO->getOpcode() == Instruction::UDiv ||
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BO->getOpcode() == Instruction::SDiv)) {
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Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);
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2011-02-06 21:44:57 +00:00
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// If the division is exact, X % Y is zero, so we end up with X or -X.
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if (PossiblyExactOperator *SDiv = dyn_cast<PossiblyExactOperator>(BO))
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2010-01-05 06:09:35 +00:00
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if (SDiv->isExact()) {
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if (Op1BO == Op1C)
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return ReplaceInstUsesWith(I, Op0BO);
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return BinaryOperator::CreateNeg(Op0BO);
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}
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Value *Rem;
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if (BO->getOpcode() == Instruction::UDiv)
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Rem = Builder->CreateURem(Op0BO, Op1BO);
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else
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Rem = Builder->CreateSRem(Op0BO, Op1BO);
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Rem->takeName(BO);
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if (Op1BO == Op1C)
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return BinaryOperator::CreateSub(Op0BO, Rem);
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return BinaryOperator::CreateSub(Rem, Op0BO);
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}
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}
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/// i1 mul -> i1 and.
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2010-02-15 16:12:20 +00:00
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if (I.getType()->isIntegerTy(1))
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2010-01-05 06:09:35 +00:00
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return BinaryOperator::CreateAnd(Op0, Op1);
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// X*(1 << Y) --> X << Y
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// (1 << Y)*X --> X << Y
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{
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Value *Y;
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if (match(Op0, m_Shl(m_One(), m_Value(Y))))
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return BinaryOperator::CreateShl(Op1, Y);
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if (match(Op1, m_Shl(m_One(), m_Value(Y))))
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return BinaryOperator::CreateShl(Op0, Y);
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}
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2013-04-05 21:20:12 +00:00
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2010-01-05 06:09:35 +00:00
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// If one of the operands of the multiply is a cast from a boolean value, then
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// we know the bool is either zero or one, so this is a 'masking' multiply.
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// X * Y (where Y is 0 or 1) -> X & (0-Y)
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2010-02-16 11:11:14 +00:00
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if (!I.getType()->isVectorTy()) {
|
2010-01-05 06:09:35 +00:00
|
|
|
// -2 is "-1 << 1" so it is all bits set except the low one.
|
|
|
|
APInt Negative2(I.getType()->getPrimitiveSizeInBits(), (uint64_t)-2, true);
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
Value *BoolCast = 0, *OtherOp = 0;
|
|
|
|
if (MaskedValueIsZero(Op0, Negative2))
|
|
|
|
BoolCast = Op0, OtherOp = Op1;
|
|
|
|
else if (MaskedValueIsZero(Op1, Negative2))
|
|
|
|
BoolCast = Op1, OtherOp = Op0;
|
|
|
|
|
|
|
|
if (BoolCast) {
|
|
|
|
Value *V = Builder->CreateSub(Constant::getNullValue(I.getType()),
|
2011-09-27 20:39:19 +00:00
|
|
|
BoolCast);
|
2010-01-05 06:09:35 +00:00
|
|
|
return BinaryOperator::CreateAnd(V, OtherOp);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return Changed ? &I : 0;
|
|
|
|
}
|
|
|
|
|
2012-11-30 22:07:05 +00:00
|
|
|
//
|
|
|
|
// Detect pattern:
|
|
|
|
//
|
|
|
|
// log2(Y*0.5)
|
|
|
|
//
|
|
|
|
// And check for corresponding fast math flags
|
|
|
|
//
|
|
|
|
|
|
|
|
static void detectLog2OfHalf(Value *&Op, Value *&Y, IntrinsicInst *&Log2) {
|
2012-11-30 22:47:15 +00:00
|
|
|
|
|
|
|
if (!Op->hasOneUse())
|
|
|
|
return;
|
|
|
|
|
|
|
|
IntrinsicInst *II = dyn_cast<IntrinsicInst>(Op);
|
|
|
|
if (!II)
|
|
|
|
return;
|
|
|
|
if (II->getIntrinsicID() != Intrinsic::log2 || !II->hasUnsafeAlgebra())
|
|
|
|
return;
|
|
|
|
Log2 = II;
|
|
|
|
|
|
|
|
Value *OpLog2Of = II->getArgOperand(0);
|
|
|
|
if (!OpLog2Of->hasOneUse())
|
|
|
|
return;
|
|
|
|
|
|
|
|
Instruction *I = dyn_cast<Instruction>(OpLog2Of);
|
|
|
|
if (!I)
|
|
|
|
return;
|
|
|
|
if (I->getOpcode() != Instruction::FMul || !I->hasUnsafeAlgebra())
|
|
|
|
return;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2012-11-30 22:47:15 +00:00
|
|
|
ConstantFP *CFP = dyn_cast<ConstantFP>(I->getOperand(0));
|
|
|
|
if (CFP && CFP->isExactlyValue(0.5)) {
|
|
|
|
Y = I->getOperand(1);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
CFP = dyn_cast<ConstantFP>(I->getOperand(1));
|
|
|
|
if (CFP && CFP->isExactlyValue(0.5))
|
|
|
|
Y = I->getOperand(0);
|
2013-04-05 21:20:12 +00:00
|
|
|
}
|
2012-11-30 22:07:05 +00:00
|
|
|
|
2013-01-07 21:39:23 +00:00
|
|
|
/// Helper function of InstCombiner::visitFMul(BinaryOperator(). It returns
|
|
|
|
/// true iff the given value is FMul or FDiv with one and only one operand
|
|
|
|
/// being a normal constant (i.e. not Zero/NaN/Infinity).
|
|
|
|
static bool isFMulOrFDivWithConstant(Value *V) {
|
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
2013-04-05 21:20:12 +00:00
|
|
|
if (!I || (I->getOpcode() != Instruction::FMul &&
|
2013-01-07 22:41:28 +00:00
|
|
|
I->getOpcode() != Instruction::FDiv))
|
2013-01-07 21:39:23 +00:00
|
|
|
return false;
|
|
|
|
|
|
|
|
ConstantFP *C0 = dyn_cast<ConstantFP>(I->getOperand(0));
|
|
|
|
ConstantFP *C1 = dyn_cast<ConstantFP>(I->getOperand(1));
|
|
|
|
|
|
|
|
if (C0 && C1)
|
|
|
|
return false;
|
|
|
|
|
2013-06-19 21:23:18 +00:00
|
|
|
return (C0 && C0->getValueAPF().isFiniteNonZero()) ||
|
|
|
|
(C1 && C1->getValueAPF().isFiniteNonZero());
|
2013-01-07 21:39:23 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static bool isNormalFp(const ConstantFP *C) {
|
|
|
|
const APFloat &Flt = C->getValueAPF();
|
2013-06-26 23:17:31 +00:00
|
|
|
return Flt.isNormal();
|
2013-01-07 21:39:23 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/// foldFMulConst() is a helper routine of InstCombiner::visitFMul().
|
|
|
|
/// The input \p FMulOrDiv is a FMul/FDiv with one and only one operand
|
|
|
|
/// being a constant (i.e. isFMulOrFDivWithConstant(FMulOrDiv) == true).
|
2013-04-05 21:20:12 +00:00
|
|
|
/// This function is to simplify "FMulOrDiv * C" and returns the
|
2013-01-07 21:39:23 +00:00
|
|
|
/// resulting expression. Note that this function could return NULL in
|
|
|
|
/// case the constants cannot be folded into a normal floating-point.
|
2013-04-05 21:20:12 +00:00
|
|
|
///
|
2013-01-07 22:41:28 +00:00
|
|
|
Value *InstCombiner::foldFMulConst(Instruction *FMulOrDiv, ConstantFP *C,
|
|
|
|
Instruction *InsertBefore) {
|
2013-01-07 21:39:23 +00:00
|
|
|
assert(isFMulOrFDivWithConstant(FMulOrDiv) && "V is invalid");
|
|
|
|
|
|
|
|
Value *Opnd0 = FMulOrDiv->getOperand(0);
|
|
|
|
Value *Opnd1 = FMulOrDiv->getOperand(1);
|
|
|
|
|
|
|
|
ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
|
|
|
|
ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
|
|
|
|
|
|
|
|
BinaryOperator *R = 0;
|
|
|
|
|
|
|
|
// (X * C0) * C => X * (C0*C)
|
|
|
|
if (FMulOrDiv->getOpcode() == Instruction::FMul) {
|
|
|
|
Constant *F = ConstantExpr::getFMul(C1 ? C1 : C0, C);
|
|
|
|
if (isNormalFp(cast<ConstantFP>(F)))
|
|
|
|
R = BinaryOperator::CreateFMul(C1 ? Opnd0 : Opnd1, F);
|
|
|
|
} else {
|
|
|
|
if (C0) {
|
|
|
|
// (C0 / X) * C => (C0 * C) / X
|
2013-09-19 21:13:46 +00:00
|
|
|
if (FMulOrDiv->hasOneUse()) {
|
|
|
|
// It would otherwise introduce another div.
|
|
|
|
ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFMul(C0, C));
|
|
|
|
if (isNormalFp(F))
|
|
|
|
R = BinaryOperator::CreateFDiv(F, Opnd1);
|
|
|
|
}
|
2013-01-07 21:39:23 +00:00
|
|
|
} else {
|
|
|
|
// (X / C1) * C => X * (C/C1) if C/C1 is not a denormal
|
|
|
|
ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFDiv(C, C1));
|
|
|
|
if (isNormalFp(F)) {
|
|
|
|
R = BinaryOperator::CreateFMul(Opnd0, F);
|
|
|
|
} else {
|
2013-04-05 21:20:12 +00:00
|
|
|
// (X / C1) * C => X / (C1/C)
|
2013-01-07 21:39:23 +00:00
|
|
|
Constant *F = ConstantExpr::getFDiv(C1, C);
|
|
|
|
if (isNormalFp(cast<ConstantFP>(F)))
|
|
|
|
R = BinaryOperator::CreateFDiv(Opnd0, F);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (R) {
|
|
|
|
R->setHasUnsafeAlgebra(true);
|
|
|
|
InsertNewInstWith(R, *InsertBefore);
|
|
|
|
}
|
|
|
|
|
|
|
|
return R;
|
|
|
|
}
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
|
2010-11-13 15:10:37 +00:00
|
|
|
bool Changed = SimplifyAssociativeOrCommutative(I);
|
2010-01-05 06:09:35 +00:00
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
2013-01-07 21:39:23 +00:00
|
|
|
if (isa<Constant>(Op0))
|
|
|
|
std::swap(Op0, Op1);
|
|
|
|
|
2012-12-12 00:28:32 +00:00
|
|
|
if (Value *V = SimplifyFMulInst(Op0, Op1, I.getFastMathFlags(), TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
2010-01-05 06:09:35 +00:00
|
|
|
|
2013-01-15 21:09:32 +00:00
|
|
|
bool AllowReassociate = I.hasUnsafeAlgebra();
|
|
|
|
|
2012-12-12 00:28:32 +00:00
|
|
|
// Simplify mul instructions with a constant RHS.
|
|
|
|
if (isa<Constant>(Op1)) {
|
2010-01-05 06:09:35 +00:00
|
|
|
// Try to fold constant mul into select arguments.
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
|
|
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
|
|
return R;
|
|
|
|
|
|
|
|
if (isa<PHINode>(Op0))
|
|
|
|
if (Instruction *NV = FoldOpIntoPhi(I))
|
|
|
|
return NV;
|
2013-01-07 21:39:23 +00:00
|
|
|
|
|
|
|
ConstantFP *C = dyn_cast<ConstantFP>(Op1);
|
2013-06-19 21:23:18 +00:00
|
|
|
if (C && AllowReassociate && C->getValueAPF().isFiniteNonZero()) {
|
2013-01-07 21:39:23 +00:00
|
|
|
// Let MDC denote an expression in one of these forms:
|
|
|
|
// X * C, C/X, X/C, where C is a constant.
|
|
|
|
//
|
|
|
|
// Try to simplify "MDC * Constant"
|
|
|
|
if (isFMulOrFDivWithConstant(Op0)) {
|
|
|
|
Value *V = foldFMulConst(cast<Instruction>(Op0), C, &I);
|
|
|
|
if (V)
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
}
|
|
|
|
|
2013-02-28 21:12:40 +00:00
|
|
|
// (MDC +/- C1) * C => (MDC * C) +/- (C1 * C)
|
2013-01-07 21:39:23 +00:00
|
|
|
Instruction *FAddSub = dyn_cast<Instruction>(Op0);
|
|
|
|
if (FAddSub &&
|
|
|
|
(FAddSub->getOpcode() == Instruction::FAdd ||
|
|
|
|
FAddSub->getOpcode() == Instruction::FSub)) {
|
|
|
|
Value *Opnd0 = FAddSub->getOperand(0);
|
|
|
|
Value *Opnd1 = FAddSub->getOperand(1);
|
|
|
|
ConstantFP *C0 = dyn_cast<ConstantFP>(Opnd0);
|
|
|
|
ConstantFP *C1 = dyn_cast<ConstantFP>(Opnd1);
|
|
|
|
bool Swap = false;
|
|
|
|
if (C0) {
|
2013-01-07 22:41:28 +00:00
|
|
|
std::swap(C0, C1);
|
|
|
|
std::swap(Opnd0, Opnd1);
|
2013-04-05 21:20:12 +00:00
|
|
|
Swap = true;
|
2013-01-07 21:39:23 +00:00
|
|
|
}
|
|
|
|
|
2013-06-19 21:23:18 +00:00
|
|
|
if (C1 && C1->getValueAPF().isFiniteNonZero() &&
|
2013-01-07 21:39:23 +00:00
|
|
|
isFMulOrFDivWithConstant(Opnd0)) {
|
2013-02-28 21:12:40 +00:00
|
|
|
Value *M1 = ConstantExpr::getFMul(C1, C);
|
2013-04-05 21:20:12 +00:00
|
|
|
Value *M0 = isNormalFp(cast<ConstantFP>(M1)) ?
|
2013-01-07 21:39:23 +00:00
|
|
|
foldFMulConst(cast<Instruction>(Opnd0), C, &I) :
|
|
|
|
0;
|
|
|
|
if (M0 && M1) {
|
|
|
|
if (Swap && FAddSub->getOpcode() == Instruction::FSub)
|
|
|
|
std::swap(M0, M1);
|
|
|
|
|
|
|
|
Value *R = (FAddSub->getOpcode() == Instruction::FAdd) ?
|
|
|
|
BinaryOperator::CreateFAdd(M0, M1) :
|
|
|
|
BinaryOperator::CreateFSub(M0, M1);
|
|
|
|
Instruction *RI = cast<Instruction>(R);
|
2013-01-15 21:09:32 +00:00
|
|
|
RI->copyFastMathFlags(&I);
|
2013-01-07 21:39:23 +00:00
|
|
|
return RI;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2012-11-30 19:09:41 +00:00
|
|
|
// Under unsafe algebra do:
|
|
|
|
// X * log2(0.5*Y) = X*log2(Y) - X
|
|
|
|
if (I.hasUnsafeAlgebra()) {
|
|
|
|
Value *OpX = NULL;
|
|
|
|
Value *OpY = NULL;
|
|
|
|
IntrinsicInst *Log2;
|
2012-11-30 22:07:05 +00:00
|
|
|
detectLog2OfHalf(Op0, OpY, Log2);
|
|
|
|
if (OpY) {
|
|
|
|
OpX = Op1;
|
|
|
|
} else {
|
|
|
|
detectLog2OfHalf(Op1, OpY, Log2);
|
|
|
|
if (OpY) {
|
|
|
|
OpX = Op0;
|
2012-11-30 19:09:41 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
// if pattern detected emit alternate sequence
|
|
|
|
if (OpX && OpY) {
|
|
|
|
Log2->setArgOperand(0, OpY);
|
|
|
|
Value *FMulVal = Builder->CreateFMul(OpX, Log2);
|
2012-11-30 22:07:05 +00:00
|
|
|
Instruction *FMul = cast<Instruction>(FMulVal);
|
2012-11-30 19:09:41 +00:00
|
|
|
FMul->copyFastMathFlags(Log2);
|
|
|
|
Instruction *FSub = BinaryOperator::CreateFSub(FMulVal, OpX);
|
|
|
|
FSub->copyFastMathFlags(Log2);
|
|
|
|
return FSub;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-01-15 21:09:32 +00:00
|
|
|
// Handle symmetric situation in a 2-iteration loop
|
|
|
|
Value *Opnd0 = Op0;
|
|
|
|
Value *Opnd1 = Op1;
|
|
|
|
for (int i = 0; i < 2; i++) {
|
|
|
|
bool IgnoreZeroSign = I.hasNoSignedZeros();
|
|
|
|
if (BinaryOperator::isFNeg(Opnd0, IgnoreZeroSign)) {
|
|
|
|
Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign);
|
|
|
|
Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
|
|
|
|
|
|
|
|
// -X * -Y => X*Y
|
|
|
|
if (N1)
|
|
|
|
return BinaryOperator::CreateFMul(N0, N1);
|
|
|
|
|
|
|
|
if (Opnd0->hasOneUse()) {
|
|
|
|
// -X * Y => -(X*Y) (Promote negation as high as possible)
|
|
|
|
Value *T = Builder->CreateFMul(N0, Opnd1);
|
|
|
|
cast<Instruction>(T)->setDebugLoc(I.getDebugLoc());
|
|
|
|
Instruction *Neg = BinaryOperator::CreateFNeg(T);
|
|
|
|
if (I.getFastMathFlags().any()) {
|
|
|
|
cast<Instruction>(T)->copyFastMathFlags(&I);
|
|
|
|
Neg->copyFastMathFlags(&I);
|
|
|
|
}
|
|
|
|
return Neg;
|
|
|
|
}
|
2012-12-14 18:46:06 +00:00
|
|
|
}
|
|
|
|
|
2013-01-15 21:09:32 +00:00
|
|
|
// (X*Y) * X => (X*X) * Y where Y != X
|
2013-04-05 21:20:12 +00:00
|
|
|
// The purpose is two-fold:
|
2013-01-15 21:09:32 +00:00
|
|
|
// 1) to form a power expression (of X).
|
|
|
|
// 2) potentially shorten the critical path: After transformation, the
|
|
|
|
// latency of the instruction Y is amortized by the expression of X*X,
|
|
|
|
// and therefore Y is in a "less critical" position compared to what it
|
|
|
|
// was before the transformation.
|
|
|
|
//
|
|
|
|
if (AllowReassociate) {
|
|
|
|
Value *Opnd0_0, *Opnd0_1;
|
|
|
|
if (Opnd0->hasOneUse() &&
|
|
|
|
match(Opnd0, m_FMul(m_Value(Opnd0_0), m_Value(Opnd0_1)))) {
|
|
|
|
Value *Y = 0;
|
|
|
|
if (Opnd0_0 == Opnd1 && Opnd0_1 != Opnd1)
|
|
|
|
Y = Opnd0_1;
|
|
|
|
else if (Opnd0_1 == Opnd1 && Opnd0_0 != Opnd1)
|
|
|
|
Y = Opnd0_0;
|
|
|
|
|
|
|
|
if (Y) {
|
|
|
|
Instruction *T = cast<Instruction>(Builder->CreateFMul(Opnd1, Opnd1));
|
|
|
|
T->copyFastMathFlags(&I);
|
|
|
|
T->setDebugLoc(I.getDebugLoc());
|
|
|
|
|
|
|
|
Instruction *R = BinaryOperator::CreateFMul(T, Y);
|
|
|
|
R->copyFastMathFlags(&I);
|
|
|
|
return R;
|
|
|
|
}
|
2012-12-14 18:46:06 +00:00
|
|
|
}
|
|
|
|
}
|
2013-01-15 21:09:32 +00:00
|
|
|
|
2013-07-17 20:06:03 +00:00
|
|
|
// B * (uitofp i1 C) -> select C, B, 0
|
|
|
|
if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
|
|
|
|
Value *LHS = Op0, *RHS = Op1;
|
|
|
|
Value *B, *C;
|
2013-07-26 17:55:00 +00:00
|
|
|
if (!match(RHS, m_UIToFP(m_Value(C))))
|
2013-07-17 20:06:03 +00:00
|
|
|
std::swap(LHS, RHS);
|
|
|
|
|
2013-07-26 17:55:00 +00:00
|
|
|
if (match(RHS, m_UIToFP(m_Value(C))) && C->getType()->isIntegerTy(1)) {
|
2013-07-17 20:06:03 +00:00
|
|
|
B = LHS;
|
|
|
|
Value *Zero = ConstantFP::getNegativeZero(B->getType());
|
|
|
|
return SelectInst::Create(C, B, Zero);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// A * (1 - uitofp i1 C) -> select C, 0, A
|
|
|
|
if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
|
|
|
|
Value *LHS = Op0, *RHS = Op1;
|
|
|
|
Value *A, *C;
|
2013-07-26 17:55:00 +00:00
|
|
|
if (!match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))))
|
2013-07-17 20:06:03 +00:00
|
|
|
std::swap(LHS, RHS);
|
|
|
|
|
2013-07-26 17:55:00 +00:00
|
|
|
if (match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))) &&
|
2013-07-17 20:06:03 +00:00
|
|
|
C->getType()->isIntegerTy(1)) {
|
|
|
|
A = LHS;
|
|
|
|
Value *Zero = ConstantFP::getNegativeZero(A->getType());
|
|
|
|
return SelectInst::Create(C, Zero, A);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-01-15 21:09:32 +00:00
|
|
|
if (!isa<Constant>(Op1))
|
|
|
|
std::swap(Opnd0, Opnd1);
|
|
|
|
else
|
|
|
|
break;
|
2012-12-14 18:46:06 +00:00
|
|
|
}
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
return Changed ? &I : 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/// SimplifyDivRemOfSelect - Try to fold a divide or remainder of a select
|
|
|
|
/// instruction.
|
|
|
|
bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
|
|
|
|
SelectInst *SI = cast<SelectInst>(I.getOperand(1));
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// div/rem X, (Cond ? 0 : Y) -> div/rem X, Y
|
|
|
|
int NonNullOperand = -1;
|
|
|
|
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(1)))
|
|
|
|
if (ST->isNullValue())
|
|
|
|
NonNullOperand = 2;
|
|
|
|
// div/rem X, (Cond ? Y : 0) -> div/rem X, Y
|
|
|
|
if (Constant *ST = dyn_cast<Constant>(SI->getOperand(2)))
|
|
|
|
if (ST->isNullValue())
|
|
|
|
NonNullOperand = 1;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
if (NonNullOperand == -1)
|
|
|
|
return false;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
Value *SelectCond = SI->getOperand(0);
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Change the div/rem to use 'Y' instead of the select.
|
|
|
|
I.setOperand(1, SI->getOperand(NonNullOperand));
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Okay, we know we replace the operand of the div/rem with 'Y' with no
|
|
|
|
// problem. However, the select, or the condition of the select may have
|
|
|
|
// multiple uses. Based on our knowledge that the operand must be non-zero,
|
|
|
|
// propagate the known value for the select into other uses of it, and
|
|
|
|
// propagate a known value of the condition into its other users.
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// If the select and condition only have a single use, don't bother with this,
|
|
|
|
// early exit.
|
|
|
|
if (SI->use_empty() && SelectCond->hasOneUse())
|
|
|
|
return true;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Scan the current block backward, looking for other uses of SI.
|
|
|
|
BasicBlock::iterator BBI = &I, BBFront = I.getParent()->begin();
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
while (BBI != BBFront) {
|
|
|
|
--BBI;
|
|
|
|
// If we found a call to a function, we can't assume it will return, so
|
|
|
|
// information from below it cannot be propagated above it.
|
|
|
|
if (isa<CallInst>(BBI) && !isa<IntrinsicInst>(BBI))
|
|
|
|
break;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Replace uses of the select or its condition with the known values.
|
|
|
|
for (Instruction::op_iterator I = BBI->op_begin(), E = BBI->op_end();
|
|
|
|
I != E; ++I) {
|
|
|
|
if (*I == SI) {
|
|
|
|
*I = SI->getOperand(NonNullOperand);
|
|
|
|
Worklist.Add(BBI);
|
|
|
|
} else if (*I == SelectCond) {
|
2013-06-06 23:34:59 +00:00
|
|
|
*I = Builder->getInt1(NonNullOperand == 1);
|
2010-01-05 06:09:35 +00:00
|
|
|
Worklist.Add(BBI);
|
|
|
|
}
|
|
|
|
}
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// If we past the instruction, quit looking for it.
|
|
|
|
if (&*BBI == SI)
|
|
|
|
SI = 0;
|
|
|
|
if (&*BBI == SelectCond)
|
|
|
|
SelectCond = 0;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// If we ran out of things to eliminate, break out of the loop.
|
|
|
|
if (SelectCond == 0 && SI == 0)
|
|
|
|
break;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/// This function implements the transforms common to both integer division
|
|
|
|
/// instructions (udiv and sdiv). It is called by the visitors to those integer
|
|
|
|
/// division instructions.
|
|
|
|
/// @brief Common integer divide transforms
|
|
|
|
Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
Carve out a place in instcombine to put transformations which work knowing that their
result is non-zero. Implement an example optimization (PR9814), which allows us to
transform:
A / ((1 << B) >>u 2)
into:
A >>u (B-2)
which we compile into:
_divu3: ## @divu3
leal -2(%rsi), %ecx
shrl %cl, %edi
movl %edi, %eax
ret
instead of:
_divu3: ## @divu3
movb %sil, %cl
movl $1, %esi
shll %cl, %esi
shrl $2, %esi
movl %edi, %eax
xorl %edx, %edx
divl %esi, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131860 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22 18:18:41 +00:00
|
|
|
// The RHS is known non-zero.
|
|
|
|
if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
|
|
|
|
I.setOperand(1, V);
|
|
|
|
return &I;
|
|
|
|
}
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Handle cases involving: [su]div X, (select Cond, Y, Z)
|
|
|
|
// This does not apply for fdiv.
|
|
|
|
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
|
|
|
|
return &I;
|
|
|
|
|
|
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
|
|
|
|
// (X / C1) / C2 -> X / (C1*C2)
|
|
|
|
if (Instruction *LHS = dyn_cast<Instruction>(Op0))
|
|
|
|
if (Instruction::BinaryOps(LHS->getOpcode()) == I.getOpcode())
|
|
|
|
if (ConstantInt *LHSRHS = dyn_cast<ConstantInt>(LHS->getOperand(1))) {
|
|
|
|
if (MultiplyOverflows(RHS, LHSRHS,
|
|
|
|
I.getOpcode()==Instruction::SDiv))
|
|
|
|
return ReplaceInstUsesWith(I, Constant::getNullValue(I.getType()));
|
2011-02-10 05:36:31 +00:00
|
|
|
return BinaryOperator::Create(I.getOpcode(), LHS->getOperand(0),
|
|
|
|
ConstantExpr::getMul(RHS, LHSRHS));
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
if (!RHS->isZero()) { // avoid X udiv 0
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
|
|
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
|
|
return R;
|
|
|
|
if (isa<PHINode>(Op0))
|
|
|
|
if (Instruction *NV = FoldOpIntoPhi(I))
|
|
|
|
return NV;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-04-30 18:16:00 +00:00
|
|
|
// See if we can fold away this div instruction.
|
|
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
|
|
return &I;
|
|
|
|
|
2011-01-28 16:51:11 +00:00
|
|
|
// (X - (X rem Y)) / Y -> X / Y; usually originates as ((X / Y) * Y) / Y
|
|
|
|
Value *X = 0, *Z = 0;
|
|
|
|
if (match(Op0, m_Sub(m_Value(X), m_Value(Z)))) { // (X - Z) / Y; Y = Op1
|
|
|
|
bool isSigned = I.getOpcode() == Instruction::SDiv;
|
|
|
|
if ((isSigned && match(Z, m_SRem(m_Specific(X), m_Specific(Op1)))) ||
|
|
|
|
(!isSigned && match(Z, m_URem(m_Specific(X), m_Specific(Op1)))))
|
|
|
|
return BinaryOperator::Create(I.getOpcode(), X, Op1);
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-04-30 18:16:07 +00:00
|
|
|
/// dyn_castZExtVal - Checks if V is a zext or constant that can
|
|
|
|
/// be truncated to Ty without losing bits.
|
2011-07-18 04:54:35 +00:00
|
|
|
static Value *dyn_castZExtVal(Value *V, Type *Ty) {
|
2011-04-30 18:16:07 +00:00
|
|
|
if (ZExtInst *Z = dyn_cast<ZExtInst>(V)) {
|
|
|
|
if (Z->getSrcTy() == Ty)
|
|
|
|
return Z->getOperand(0);
|
|
|
|
} else if (ConstantInt *C = dyn_cast<ConstantInt>(V)) {
|
|
|
|
if (C->getValue().getActiveBits() <= cast<IntegerType>(Ty)->getBitWidth())
|
|
|
|
return ConstantExpr::getTrunc(C, Ty);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
namespace {
|
|
|
|
const unsigned MaxDepth = 6;
|
|
|
|
typedef Instruction *(*FoldUDivOperandCb)(Value *Op0, Value *Op1,
|
|
|
|
const BinaryOperator &I,
|
|
|
|
InstCombiner &IC);
|
|
|
|
|
|
|
|
/// \brief Used to maintain state for visitUDivOperand().
|
|
|
|
struct UDivFoldAction {
|
|
|
|
FoldUDivOperandCb FoldAction; ///< Informs visitUDiv() how to fold this
|
|
|
|
///< operand. This can be zero if this action
|
|
|
|
///< joins two actions together.
|
|
|
|
|
|
|
|
Value *OperandToFold; ///< Which operand to fold.
|
|
|
|
union {
|
|
|
|
Instruction *FoldResult; ///< The instruction returned when FoldAction is
|
|
|
|
///< invoked.
|
|
|
|
|
|
|
|
size_t SelectLHSIdx; ///< Stores the LHS action index if this action
|
|
|
|
///< joins two actions together.
|
|
|
|
};
|
|
|
|
|
|
|
|
UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand)
|
|
|
|
: FoldAction(FA), OperandToFold(InputOperand), FoldResult(0) {}
|
|
|
|
UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS)
|
|
|
|
: FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {}
|
|
|
|
};
|
|
|
|
}
|
Revert r185257 (InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms)
I'm reverting this commit because:
1. As discussed during review, it needs to be rewritten (to avoid creating and
then deleting instructions).
2. This is causing optimizer crashes. Specifically, I'm seeing things like
this:
While deleting: i1 %
Use still stuck around after Def is destroyed: <badref> = select i1 <badref>, i32 0, i32 1
opt: /src/llvm-trunk/lib/IR/Value.cpp:79: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed.
I'd guess that these will go away once we're no longer creating/deleting
instructions here, but just in case, I'm adding a regression test.
Because the code is bring rewritten, I've just XFAIL'd the original regression test. Original commit message:
InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms
Real world code sometimes has the denominator of a 'udiv' be a
'select'. LLVM can handle such cases but only when the 'select'
operands are symmetric in structure (both select operands are a constant
power of two or a left shift, etc.). This falls apart if we are dealt a
'udiv' where the code is not symetric or if the select operands lead us
to more select instructions.
Instead, we should treat the LHS and each select operand as a distinct
divide operation and try to optimize them independently. If we can
to simplify each operation, then we can replace the 'udiv' with, say, a
'lshr' that has a new select with a bunch of new operands for the
select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185415 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-02 05:21:11 +00:00
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
// X udiv 2^C -> X >> C
|
|
|
|
static Instruction *foldUDivPow2Cst(Value *Op0, Value *Op1,
|
|
|
|
const BinaryOperator &I, InstCombiner &IC) {
|
|
|
|
const APInt &C = cast<Constant>(Op1)->getUniqueInteger();
|
|
|
|
BinaryOperator *LShr = BinaryOperator::CreateLShr(
|
|
|
|
Op0, ConstantInt::get(Op0->getType(), C.logBase2()));
|
|
|
|
if (I.isExact()) LShr->setIsExact();
|
|
|
|
return LShr;
|
|
|
|
}
|
Revert r185257 (InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms)
I'm reverting this commit because:
1. As discussed during review, it needs to be rewritten (to avoid creating and
then deleting instructions).
2. This is causing optimizer crashes. Specifically, I'm seeing things like
this:
While deleting: i1 %
Use still stuck around after Def is destroyed: <badref> = select i1 <badref>, i32 0, i32 1
opt: /src/llvm-trunk/lib/IR/Value.cpp:79: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed.
I'd guess that these will go away once we're no longer creating/deleting
instructions here, but just in case, I'm adding a regression test.
Because the code is bring rewritten, I've just XFAIL'd the original regression test. Original commit message:
InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms
Real world code sometimes has the denominator of a 'udiv' be a
'select'. LLVM can handle such cases but only when the 'select'
operands are symmetric in structure (both select operands are a constant
power of two or a left shift, etc.). This falls apart if we are dealt a
'udiv' where the code is not symetric or if the select operands lead us
to more select instructions.
Instead, we should treat the LHS and each select operand as a distinct
divide operation and try to optimize them independently. If we can
to simplify each operation, then we can replace the 'udiv' with, say, a
'lshr' that has a new select with a bunch of new operands for the
select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185415 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-02 05:21:11 +00:00
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
// X udiv C, where C >= signbit
|
|
|
|
static Instruction *foldUDivNegCst(Value *Op0, Value *Op1,
|
|
|
|
const BinaryOperator &I, InstCombiner &IC) {
|
|
|
|
Value *ICI = IC.Builder->CreateICmpULT(Op0, cast<ConstantInt>(Op1));
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
return SelectInst::Create(ICI, Constant::getNullValue(I.getType()),
|
|
|
|
ConstantInt::get(I.getType(), 1));
|
|
|
|
}
|
|
|
|
|
|
|
|
// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2)
|
|
|
|
static Instruction *foldUDivShl(Value *Op0, Value *Op1, const BinaryOperator &I,
|
|
|
|
InstCombiner &IC) {
|
|
|
|
Instruction *ShiftLeft = cast<Instruction>(Op1);
|
|
|
|
if (isa<ZExtInst>(ShiftLeft))
|
|
|
|
ShiftLeft = cast<Instruction>(ShiftLeft->getOperand(0));
|
|
|
|
|
|
|
|
const APInt &CI =
|
|
|
|
cast<Constant>(ShiftLeft->getOperand(0))->getUniqueInteger();
|
|
|
|
Value *N = ShiftLeft->getOperand(1);
|
|
|
|
if (CI != 1)
|
|
|
|
N = IC.Builder->CreateAdd(N, ConstantInt::get(N->getType(), CI.logBase2()));
|
|
|
|
if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
|
|
|
|
N = IC.Builder->CreateZExt(N, Z->getDestTy());
|
|
|
|
BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N);
|
|
|
|
if (I.isExact()) LShr->setIsExact();
|
|
|
|
return LShr;
|
|
|
|
}
|
|
|
|
|
|
|
|
// \brief Recursively visits the possible right hand operands of a udiv
|
|
|
|
// instruction, seeing through select instructions, to determine if we can
|
|
|
|
// replace the udiv with something simpler. If we find that an operand is not
|
|
|
|
// able to simplify the udiv, we abort the entire transformation.
|
|
|
|
static size_t visitUDivOperand(Value *Op0, Value *Op1, const BinaryOperator &I,
|
|
|
|
SmallVectorImpl<UDivFoldAction> &Actions,
|
|
|
|
unsigned Depth = 0) {
|
|
|
|
// Check to see if this is an unsigned division with an exact power of 2,
|
|
|
|
// if so, convert to a right shift.
|
|
|
|
if (match(Op1, m_Power2())) {
|
|
|
|
Actions.push_back(UDivFoldAction(foldUDivPow2Cst, Op1));
|
|
|
|
return Actions.size();
|
2011-11-07 23:04:49 +00:00
|
|
|
}
|
2010-01-05 06:09:35 +00:00
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
if (ConstantInt *C = dyn_cast<ConstantInt>(Op1))
|
2010-01-05 06:09:35 +00:00
|
|
|
// X udiv C, where C >= signbit
|
|
|
|
if (C->getValue().isNegative()) {
|
2013-07-04 21:17:49 +00:00
|
|
|
Actions.push_back(UDivFoldAction(foldUDivNegCst, C));
|
|
|
|
return Actions.size();
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
2013-07-04 21:17:49 +00:00
|
|
|
|
|
|
|
// X udiv (C1 << N), where C1 is "1<<C2" --> X >> (N+C2)
|
|
|
|
if (match(Op1, m_Shl(m_Power2(), m_Value())) ||
|
|
|
|
match(Op1, m_ZExt(m_Shl(m_Power2(), m_Value())))) {
|
|
|
|
Actions.push_back(UDivFoldAction(foldUDivShl, Op1));
|
|
|
|
return Actions.size();
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
// The remaining tests are all recursive, so bail out if we hit the limit.
|
|
|
|
if (Depth++ == MaxDepth)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
|
|
|
|
if (size_t LHSIdx = visitUDivOperand(Op0, SI->getOperand(1), I, Actions))
|
|
|
|
if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions)) {
|
|
|
|
Actions.push_back(UDivFoldAction((FoldUDivOperandCb)0, Op1, LHSIdx-1));
|
|
|
|
return Actions.size();
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
|
|
|
if (Value *V = SimplifyUDivInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
|
|
|
// Handle the integer div common cases
|
|
|
|
if (Instruction *Common = commonIDivTransforms(I))
|
|
|
|
return Common;
|
|
|
|
|
Revert r185257 (InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms)
I'm reverting this commit because:
1. As discussed during review, it needs to be rewritten (to avoid creating and
then deleting instructions).
2. This is causing optimizer crashes. Specifically, I'm seeing things like
this:
While deleting: i1 %
Use still stuck around after Def is destroyed: <badref> = select i1 <badref>, i32 0, i32 1
opt: /src/llvm-trunk/lib/IR/Value.cpp:79: virtual llvm::Value::~Value(): Assertion `use_empty() && "Uses remain when a value is destroyed!"' failed.
I'd guess that these will go away once we're no longer creating/deleting
instructions here, but just in case, I'm adding a regression test.
Because the code is bring rewritten, I've just XFAIL'd the original regression test. Original commit message:
InstCombine: Be more agressive optimizing 'udiv' instrs with 'select' denoms
Real world code sometimes has the denominator of a 'udiv' be a
'select'. LLVM can handle such cases but only when the 'select'
operands are symmetric in structure (both select operands are a constant
power of two or a left shift, etc.). This falls apart if we are dealt a
'udiv' where the code is not symetric or if the select operands lead us
to more select instructions.
Instead, we should treat the LHS and each select operand as a distinct
divide operation and try to optimize them independently. If we can
to simplify each operation, then we can replace the 'udiv' with, say, a
'lshr' that has a new select with a bunch of new operands for the
select.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185415 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-02 05:21:11 +00:00
|
|
|
// (x lshr C1) udiv C2 --> x udiv (C2 << C1)
|
|
|
|
if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
|
|
|
|
Value *X;
|
|
|
|
ConstantInt *C1;
|
|
|
|
if (match(Op0, m_LShr(m_Value(X), m_ConstantInt(C1)))) {
|
|
|
|
APInt NC = C2->getValue().shl(C1->getLimitedValue(C1->getBitWidth()-1));
|
|
|
|
return BinaryOperator::CreateUDiv(X, Builder->getInt(NC));
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-04-30 18:16:07 +00:00
|
|
|
// (zext A) udiv (zext B) --> zext (A udiv B)
|
|
|
|
if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
|
|
|
|
if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
|
|
|
|
return new ZExtInst(Builder->CreateUDiv(ZOp0->getOperand(0), ZOp1, "div",
|
|
|
|
I.isExact()),
|
|
|
|
I.getType());
|
|
|
|
|
2013-07-04 21:17:49 +00:00
|
|
|
// (LHS udiv (select (select (...)))) -> (LHS >> (select (select (...))))
|
|
|
|
SmallVector<UDivFoldAction, 6> UDivActions;
|
|
|
|
if (visitUDivOperand(Op0, Op1, I, UDivActions))
|
|
|
|
for (unsigned i = 0, e = UDivActions.size(); i != e; ++i) {
|
|
|
|
FoldUDivOperandCb Action = UDivActions[i].FoldAction;
|
|
|
|
Value *ActionOp1 = UDivActions[i].OperandToFold;
|
|
|
|
Instruction *Inst;
|
|
|
|
if (Action)
|
|
|
|
Inst = Action(Op0, ActionOp1, I, *this);
|
|
|
|
else {
|
|
|
|
// This action joins two actions together. The RHS of this action is
|
|
|
|
// simply the last action we processed, we saved the LHS action index in
|
|
|
|
// the joining action.
|
|
|
|
size_t SelectRHSIdx = i - 1;
|
|
|
|
Value *SelectRHS = UDivActions[SelectRHSIdx].FoldResult;
|
|
|
|
size_t SelectLHSIdx = UDivActions[i].SelectLHSIdx;
|
|
|
|
Value *SelectLHS = UDivActions[SelectLHSIdx].FoldResult;
|
|
|
|
Inst = SelectInst::Create(cast<SelectInst>(ActionOp1)->getCondition(),
|
|
|
|
SelectLHS, SelectRHS);
|
|
|
|
}
|
|
|
|
|
|
|
|
// If this is the last action to process, return it to the InstCombiner.
|
|
|
|
// Otherwise, we insert it before the UDiv and record it so that we may
|
|
|
|
// use it as part of a joining action (i.e., a SelectInst).
|
|
|
|
if (e - i != 1) {
|
|
|
|
Inst->insertBefore(&I);
|
|
|
|
UDivActions[i].FoldResult = Inst;
|
|
|
|
} else
|
|
|
|
return Inst;
|
|
|
|
}
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
2011-01-28 16:51:11 +00:00
|
|
|
if (Value *V = SimplifySDivInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Handle the integer div common cases
|
|
|
|
if (Instruction *Common = commonIDivTransforms(I))
|
|
|
|
return Common;
|
|
|
|
|
|
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
|
|
|
|
// sdiv X, -1 == -X
|
|
|
|
if (RHS->isAllOnesValue())
|
|
|
|
return BinaryOperator::CreateNeg(Op0);
|
|
|
|
|
2011-02-10 05:36:31 +00:00
|
|
|
// sdiv X, C --> ashr exact X, log2(C)
|
|
|
|
if (I.isExact() && RHS->getValue().isNonNegative() &&
|
2010-01-05 06:09:35 +00:00
|
|
|
RHS->getValue().isPowerOf2()) {
|
|
|
|
Value *ShAmt = llvm::ConstantInt::get(RHS->getType(),
|
|
|
|
RHS->getValue().exactLogBase2());
|
2011-02-10 05:36:31 +00:00
|
|
|
return BinaryOperator::CreateExactAShr(Op0, ShAmt, I.getName());
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
// -X/C --> X/-C provided the negation doesn't overflow.
|
|
|
|
if (SubOperator *Sub = dyn_cast<SubOperator>(Op0))
|
2011-02-10 05:36:31 +00:00
|
|
|
if (match(Sub->getOperand(0), m_Zero()) && Sub->hasNoSignedWrap())
|
2010-01-05 06:09:35 +00:00
|
|
|
return BinaryOperator::CreateSDiv(Sub->getOperand(1),
|
|
|
|
ConstantExpr::getNeg(RHS));
|
|
|
|
}
|
|
|
|
|
|
|
|
// If the sign bits of both operands are zero (i.e. we can prove they are
|
|
|
|
// unsigned inputs), turn this into a udiv.
|
2010-02-15 16:12:20 +00:00
|
|
|
if (I.getType()->isIntegerTy()) {
|
2010-01-05 06:09:35 +00:00
|
|
|
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
|
|
|
|
if (MaskedValueIsZero(Op0, Mask)) {
|
|
|
|
if (MaskedValueIsZero(Op1, Mask)) {
|
2012-09-27 10:14:43 +00:00
|
|
|
// X sdiv Y -> X udiv Y, iff X and Y don't have sign bit set
|
2010-01-05 06:09:35 +00:00
|
|
|
return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
|
|
|
|
}
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2011-02-10 05:36:31 +00:00
|
|
|
if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
|
2010-01-05 06:09:35 +00:00
|
|
|
// X sdiv (1 << Y) -> X udiv (1 << Y) ( -> X u>> Y)
|
|
|
|
// Safe because the only negative value (1 << Y) can take on is
|
|
|
|
// INT_MIN, and X sdiv INT_MIN == X udiv INT_MIN == 0 if X doesn't have
|
|
|
|
// the sign bit set.
|
|
|
|
return BinaryOperator::CreateUDiv(Op0, Op1, I.getName());
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2013-01-14 22:48:41 +00:00
|
|
|
/// CvtFDivConstToReciprocal tries to convert X/C into X*1/C if C not a special
|
|
|
|
/// FP value and:
|
2013-04-05 21:20:12 +00:00
|
|
|
/// 1) 1/C is exact, or
|
2013-01-14 22:48:41 +00:00
|
|
|
/// 2) reciprocal is allowed.
|
2013-05-14 23:36:24 +00:00
|
|
|
/// If the conversion was successful, the simplified expression "X * 1/C" is
|
2013-01-14 22:48:41 +00:00
|
|
|
/// returned; otherwise, NULL is returned.
|
|
|
|
///
|
|
|
|
static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
|
|
|
|
ConstantFP *Divisor,
|
|
|
|
bool AllowReciprocal) {
|
|
|
|
const APFloat &FpVal = Divisor->getValueAPF();
|
|
|
|
APFloat Reciprocal(FpVal.getSemantics());
|
|
|
|
bool Cvt = FpVal.getExactInverse(&Reciprocal);
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2013-06-19 21:23:18 +00:00
|
|
|
if (!Cvt && AllowReciprocal && FpVal.isFiniteNonZero()) {
|
2013-01-14 22:48:41 +00:00
|
|
|
Reciprocal = APFloat(FpVal.getSemantics(), 1.0f);
|
|
|
|
(void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven);
|
|
|
|
Cvt = !Reciprocal.isDenormal();
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!Cvt)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
ConstantFP *R;
|
|
|
|
R = ConstantFP::get(Dividend->getType()->getContext(), Reciprocal);
|
|
|
|
return BinaryOperator::CreateFMul(Dividend, R);
|
|
|
|
}
|
|
|
|
|
2011-01-29 17:50:27 +00:00
|
|
|
Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
|
|
|
if (Value *V = SimplifyFDivInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
2013-07-20 07:13:13 +00:00
|
|
|
if (isa<Constant>(Op0))
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
|
|
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
|
|
return R;
|
|
|
|
|
2013-01-14 22:48:41 +00:00
|
|
|
bool AllowReassociate = I.hasUnsafeAlgebra();
|
|
|
|
bool AllowReciprocal = I.hasAllowReciprocal();
|
|
|
|
|
2011-03-30 15:42:35 +00:00
|
|
|
if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
|
2013-07-20 07:13:13 +00:00
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
|
|
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
|
|
return R;
|
|
|
|
|
2013-01-14 22:48:41 +00:00
|
|
|
if (AllowReassociate) {
|
|
|
|
ConstantFP *C1 = 0;
|
|
|
|
ConstantFP *C2 = Op1C;
|
|
|
|
Value *X;
|
|
|
|
Instruction *Res = 0;
|
|
|
|
|
|
|
|
if (match(Op0, m_FMul(m_Value(X), m_ConstantFP(C1)))) {
|
|
|
|
// (X*C1)/C2 => X * (C1/C2)
|
|
|
|
//
|
|
|
|
Constant *C = ConstantExpr::getFDiv(C1, C2);
|
|
|
|
const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
|
2013-06-26 23:17:31 +00:00
|
|
|
if (F.isNormal())
|
2013-01-14 22:48:41 +00:00
|
|
|
Res = BinaryOperator::CreateFMul(X, C);
|
|
|
|
} else if (match(Op0, m_FDiv(m_Value(X), m_ConstantFP(C1)))) {
|
|
|
|
// (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed]
|
|
|
|
//
|
|
|
|
Constant *C = ConstantExpr::getFMul(C1, C2);
|
|
|
|
const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
|
2013-06-26 23:17:31 +00:00
|
|
|
if (F.isNormal()) {
|
2013-04-05 21:20:12 +00:00
|
|
|
Res = CvtFDivConstToReciprocal(X, cast<ConstantFP>(C),
|
2013-01-14 22:48:41 +00:00
|
|
|
AllowReciprocal);
|
|
|
|
if (!Res)
|
2013-04-05 21:20:12 +00:00
|
|
|
Res = BinaryOperator::CreateFDiv(X, C);
|
2013-01-14 22:48:41 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (Res) {
|
|
|
|
Res->setFastMathFlags(I.getFastMathFlags());
|
|
|
|
return Res;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// X / C => X * 1/C
|
|
|
|
if (Instruction *T = CvtFDivConstToReciprocal(Op0, Op1C, AllowReciprocal))
|
|
|
|
return T;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (AllowReassociate && isa<ConstantFP>(Op0)) {
|
|
|
|
ConstantFP *C1 = cast<ConstantFP>(Op0), *C2;
|
|
|
|
Constant *Fold = 0;
|
|
|
|
Value *X;
|
|
|
|
bool CreateDiv = true;
|
|
|
|
|
|
|
|
// C1 / (X*C2) => (C1/C2) / X
|
|
|
|
if (match(Op1, m_FMul(m_Value(X), m_ConstantFP(C2))))
|
|
|
|
Fold = ConstantExpr::getFDiv(C1, C2);
|
|
|
|
else if (match(Op1, m_FDiv(m_Value(X), m_ConstantFP(C2)))) {
|
|
|
|
// C1 / (X/C2) => (C1*C2) / X
|
|
|
|
Fold = ConstantExpr::getFMul(C1, C2);
|
|
|
|
} else if (match(Op1, m_FDiv(m_ConstantFP(C2), m_Value(X)))) {
|
|
|
|
// C1 / (C2/X) => (C1/C2) * X
|
|
|
|
Fold = ConstantExpr::getFDiv(C1, C2);
|
|
|
|
CreateDiv = false;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (Fold) {
|
|
|
|
const APFloat &FoldC = cast<ConstantFP>(Fold)->getValueAPF();
|
2013-06-26 23:17:31 +00:00
|
|
|
if (FoldC.isNormal()) {
|
2013-04-05 21:20:12 +00:00
|
|
|
Instruction *R = CreateDiv ?
|
2013-01-14 22:48:41 +00:00
|
|
|
BinaryOperator::CreateFDiv(Fold, X) :
|
|
|
|
BinaryOperator::CreateFMul(X, Fold);
|
|
|
|
R->setFastMathFlags(I.getFastMathFlags());
|
|
|
|
return R;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (AllowReassociate) {
|
|
|
|
Value *X, *Y;
|
|
|
|
Value *NewInst = 0;
|
|
|
|
Instruction *SimpR = 0;
|
|
|
|
|
|
|
|
if (Op0->hasOneUse() && match(Op0, m_FDiv(m_Value(X), m_Value(Y)))) {
|
|
|
|
// (X/Y) / Z => X / (Y*Z)
|
|
|
|
//
|
|
|
|
if (!isa<ConstantFP>(Y) || !isa<ConstantFP>(Op1)) {
|
|
|
|
NewInst = Builder->CreateFMul(Y, Op1);
|
|
|
|
SimpR = BinaryOperator::CreateFDiv(X, NewInst);
|
|
|
|
}
|
|
|
|
} else if (Op1->hasOneUse() && match(Op1, m_FDiv(m_Value(X), m_Value(Y)))) {
|
|
|
|
// Z / (X/Y) => Z*Y / X
|
|
|
|
//
|
|
|
|
if (!isa<ConstantFP>(Y) || !isa<ConstantFP>(Op0)) {
|
|
|
|
NewInst = Builder->CreateFMul(Op0, Y);
|
|
|
|
SimpR = BinaryOperator::CreateFDiv(NewInst, X);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (NewInst) {
|
|
|
|
if (Instruction *T = dyn_cast<Instruction>(NewInst))
|
|
|
|
T->setDebugLoc(I.getDebugLoc());
|
|
|
|
SimpR->setFastMathFlags(I.getFastMathFlags());
|
|
|
|
return SimpR;
|
2011-03-30 15:42:35 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-01-29 17:50:27 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
/// This function implements the transforms common to both integer remainder
|
|
|
|
/// instructions (urem and srem). It is called by the visitors to those integer
|
|
|
|
/// remainder instructions.
|
|
|
|
/// @brief Common integer remainder transforms
|
|
|
|
Instruction *InstCombiner::commonIRemTransforms(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
Carve out a place in instcombine to put transformations which work knowing that their
result is non-zero. Implement an example optimization (PR9814), which allows us to
transform:
A / ((1 << B) >>u 2)
into:
A >>u (B-2)
which we compile into:
_divu3: ## @divu3
leal -2(%rsi), %ecx
shrl %cl, %edi
movl %edi, %eax
ret
instead of:
_divu3: ## @divu3
movb %sil, %cl
movl $1, %esi
shll %cl, %esi
shrl $2, %esi
movl %edi, %eax
xorl %edx, %edx
divl %esi, %eax
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131860 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-22 18:18:41 +00:00
|
|
|
// The RHS is known non-zero.
|
|
|
|
if (Value *V = simplifyValueKnownNonZero(I.getOperand(1), *this)) {
|
|
|
|
I.setOperand(1, V);
|
|
|
|
return &I;
|
|
|
|
}
|
|
|
|
|
2011-05-02 16:27:02 +00:00
|
|
|
// Handle cases involving: rem X, (select Cond, Y, Z)
|
|
|
|
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
|
|
|
|
return &I;
|
2010-01-05 06:09:35 +00:00
|
|
|
|
2011-05-02 18:41:29 +00:00
|
|
|
if (isa<ConstantInt>(Op1)) {
|
2010-01-05 06:09:35 +00:00
|
|
|
if (Instruction *Op0I = dyn_cast<Instruction>(Op0)) {
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(Op0I)) {
|
|
|
|
if (Instruction *R = FoldOpIntoSelect(I, SI))
|
|
|
|
return R;
|
|
|
|
} else if (isa<PHINode>(Op0I)) {
|
|
|
|
if (Instruction *NV = FoldOpIntoPhi(I))
|
|
|
|
return NV;
|
|
|
|
}
|
|
|
|
|
|
|
|
// See if we can fold away this rem instruction.
|
|
|
|
if (SimplifyDemandedInstructionBits(I))
|
|
|
|
return &I;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
Instruction *InstCombiner::visitURem(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
2011-05-02 16:27:02 +00:00
|
|
|
if (Value *V = SimplifyURemInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
if (Instruction *common = commonIRemTransforms(I))
|
|
|
|
return common;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2013-05-12 00:07:05 +00:00
|
|
|
// (zext A) urem (zext B) --> zext (A urem B)
|
|
|
|
if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
|
|
|
|
if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
|
|
|
|
return new ZExtInst(Builder->CreateURem(ZOp0->getOperand(0), ZOp1),
|
|
|
|
I.getType());
|
|
|
|
|
2013-05-11 09:01:28 +00:00
|
|
|
// X urem Y -> X and Y-1, where Y is a power of 2,
|
|
|
|
if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true)) {
|
2011-02-10 05:36:31 +00:00
|
|
|
Constant *N1 = Constant::getAllOnesValue(I.getType());
|
2011-09-27 20:39:19 +00:00
|
|
|
Value *Add = Builder->CreateAdd(Op1, N1);
|
2011-02-10 05:36:31 +00:00
|
|
|
return BinaryOperator::CreateAnd(Op0, Add);
|
2010-01-05 06:09:35 +00:00
|
|
|
}
|
|
|
|
|
2013-07-13 01:16:47 +00:00
|
|
|
// 1 urem X -> zext(X != 1)
|
|
|
|
if (match(Op0, m_One())) {
|
|
|
|
Value *Cmp = Builder->CreateICmpNE(Op1, Op0);
|
|
|
|
Value *Ext = Builder->CreateZExt(Cmp, I.getType());
|
|
|
|
return ReplaceInstUsesWith(I, Ext);
|
|
|
|
}
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
Instruction *InstCombiner::visitSRem(BinaryOperator &I) {
|
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
|
|
|
|
2011-05-02 16:27:02 +00:00
|
|
|
if (Value *V = SimplifySRemInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
// Handle the integer rem common cases
|
|
|
|
if (Instruction *Common = commonIRemTransforms(I))
|
|
|
|
return Common;
|
2013-04-05 21:20:12 +00:00
|
|
|
|
2010-01-05 06:09:35 +00:00
|
|
|
if (Value *RHSNeg = dyn_castNegVal(Op1))
|
|
|
|
if (!isa<Constant>(RHSNeg) ||
|
|
|
|
(isa<ConstantInt>(RHSNeg) &&
|
|
|
|
cast<ConstantInt>(RHSNeg)->getValue().isStrictlyPositive())) {
|
|
|
|
// X % -Y -> X % Y
|
|
|
|
Worklist.AddValue(I.getOperand(1));
|
|
|
|
I.setOperand(1, RHSNeg);
|
|
|
|
return &I;
|
|
|
|
}
|
|
|
|
|
|
|
|
// If the sign bits of both operands are zero (i.e. we can prove they are
|
|
|
|
// unsigned inputs), turn this into a urem.
|
2010-02-15 16:12:20 +00:00
|
|
|
if (I.getType()->isIntegerTy()) {
|
2010-01-05 06:09:35 +00:00
|
|
|
APInt Mask(APInt::getSignBit(I.getType()->getPrimitiveSizeInBits()));
|
|
|
|
if (MaskedValueIsZero(Op1, Mask) && MaskedValueIsZero(Op0, Mask)) {
|
2012-09-27 10:14:43 +00:00
|
|
|
// X srem Y -> X urem Y, iff X and Y don't have sign bit set
|
2010-01-05 06:09:35 +00:00
|
|
|
return BinaryOperator::CreateURem(Op0, Op1, I.getName());
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// If it's a constant vector, flip any negative values positive.
|
2012-01-27 03:08:05 +00:00
|
|
|
if (isa<ConstantVector>(Op1) || isa<ConstantDataVector>(Op1)) {
|
|
|
|
Constant *C = cast<Constant>(Op1);
|
|
|
|
unsigned VWidth = C->getType()->getVectorNumElements();
|
2010-01-05 06:09:35 +00:00
|
|
|
|
|
|
|
bool hasNegative = false;
|
2012-01-27 03:08:05 +00:00
|
|
|
bool hasMissing = false;
|
|
|
|
for (unsigned i = 0; i != VWidth; ++i) {
|
|
|
|
Constant *Elt = C->getAggregateElement(i);
|
|
|
|
if (Elt == 0) {
|
|
|
|
hasMissing = true;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elt))
|
2011-07-15 06:08:15 +00:00
|
|
|
if (RHS->isNegative())
|
2010-01-05 06:09:35 +00:00
|
|
|
hasNegative = true;
|
2012-01-27 03:08:05 +00:00
|
|
|
}
|
2010-01-05 06:09:35 +00:00
|
|
|
|
2012-01-27 03:08:05 +00:00
|
|
|
if (hasNegative && !hasMissing) {
|
2012-01-25 06:02:56 +00:00
|
|
|
SmallVector<Constant *, 16> Elts(VWidth);
|
2010-01-05 06:09:35 +00:00
|
|
|
for (unsigned i = 0; i != VWidth; ++i) {
|
2012-02-06 21:56:39 +00:00
|
|
|
Elts[i] = C->getAggregateElement(i); // Handle undef, etc.
|
2012-01-27 03:08:05 +00:00
|
|
|
if (ConstantInt *RHS = dyn_cast<ConstantInt>(Elts[i])) {
|
2011-07-15 06:08:15 +00:00
|
|
|
if (RHS->isNegative())
|
2010-01-05 06:09:35 +00:00
|
|
|
Elts[i] = cast<ConstantInt>(ConstantExpr::getNeg(RHS));
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
Constant *NewRHSV = ConstantVector::get(Elts);
|
2012-01-27 03:08:05 +00:00
|
|
|
if (NewRHSV != C) { // Don't loop on -MININT
|
2010-01-05 06:09:35 +00:00
|
|
|
Worklist.AddValue(I.getOperand(1));
|
|
|
|
I.setOperand(1, NewRHSV);
|
|
|
|
return &I;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
Instruction *InstCombiner::visitFRem(BinaryOperator &I) {
|
2011-05-02 16:27:02 +00:00
|
|
|
Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
|
2010-01-05 06:09:35 +00:00
|
|
|
|
2011-05-02 16:27:02 +00:00
|
|
|
if (Value *V = SimplifyFRemInst(Op0, Op1, TD))
|
|
|
|
return ReplaceInstUsesWith(I, V);
|
|
|
|
|
|
|
|
// Handle cases involving: rem X, (select Cond, Y, Z)
|
|
|
|
if (isa<SelectInst>(Op1) && SimplifyDivRemOfSelect(I))
|
|
|
|
return &I;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|