[llvm-commits] [llvm] r125264 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
Chris Lattner
sabre at nondot.org
Wed Feb 9 21:14:58 PST 2011
Author: lattner
Date: Wed Feb 9 23:14:58 2011
New Revision: 125264
URL: http://llvm.org/viewvc/llvm-project?rev=125264&view=rev
Log:
A bunch of cleanups and simplifications using the new PatternMatch predicates
and generally tidying things up. Only very trivial functionality changes
like now doing (-1 - A) -> (~A) for vectors too.
InstCombineAddSub.cpp | 296 +++++++++++++++++++++-----------------------------
1 file changed, 126 insertions(+), 170 deletions(-)
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=125264&r1=125263&r2=125264&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Wed Feb 9 23:14:58 2011
@@ -95,35 +95,26 @@
if (Value *V = SimplifyUsingDistributiveLaws(I))
return ReplaceInstUsesWith(I, V);
- if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
- if (ConstantInt *CI = dyn_cast<ConstantInt>(RHSC)) {
- // X + (signbit) --> X ^ signbit
- const APInt& Val = CI->getValue();
- uint32_t BitWidth = Val.getBitWidth();
- if (Val == APInt::getSignBit(BitWidth))
- return BinaryOperator::CreateXor(LHS, RHS);
-
- // See if SimplifyDemandedBits can simplify this. This handles stuff like
- // (X & 254)+1 -> (X&254)|1
- if (SimplifyDemandedInstructionBits(I))
- return &I;
-
- // zext(bool) + C -> bool ? C + 1 : C
- if (ZExtInst *ZI = dyn_cast<ZExtInst>(LHS))
- if (ZI->getSrcTy() == Type::getInt1Ty(I.getContext()))
- return SelectInst::Create(ZI->getOperand(0), AddOne(CI), CI);
- }
-
- if (isa<PHINode>(LHS))
- if (Instruction *NV = FoldOpIntoPhi(I))
- return NV;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+ // X + (signbit) --> X ^ signbit
+ const APInt &Val = CI->getValue();
+ if (Val.isSignBit())
+ return BinaryOperator::CreateXor(LHS, RHS);
- ConstantInt *XorRHS = 0;
- Value *XorLHS = 0;
- if (isa<ConstantInt>(RHSC) &&
- match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
+ // See if SimplifyDemandedBits can simplify this. This handles stuff like
+ // (X & 254)+1 -> (X&254)|1
+ if (SimplifyDemandedInstructionBits(I))
+ return &I;
+
+ // zext(bool) + C -> bool ? C + 1 : C
+ if (ZExtInst *ZI = dyn_cast<ZExtInst>(LHS))
+ if (ZI->getSrcTy()->isIntegerTy(1))
+ return SelectInst::Create(ZI->getOperand(0), AddOne(CI), CI);
+
+ Value *XorLHS = 0; ConstantInt *XorRHS = 0;
+ if (match(LHS, m_Xor(m_Value(XorLHS), m_ConstantInt(XorRHS)))) {
uint32_t TySizeBits = I.getType()->getScalarSizeInBits();
- const APInt& RHSVal = cast<ConstantInt>(RHSC)->getValue();
+ const APInt &RHSVal = CI->getValue();
unsigned ExtendAmt = 0;
// If we have ADD(XOR(AND(X, 0xFF), 0x80), 0xF..F80), it's a sext.
// If we have ADD(XOR(AND(X, 0xFF), 0xF..F80), 0x80), it's a sext.
@@ -133,13 +124,13 @@
else if (XorRHS->getValue().isPowerOf2())
ExtendAmt = TySizeBits - XorRHS->getValue().logBase2() - 1;
}
-
+
if (ExtendAmt) {
APInt Mask = APInt::getHighBitsSet(TySizeBits, ExtendAmt);
if (!MaskedValueIsZero(XorLHS, Mask))
ExtendAmt = 0;
}
-
+
if (ExtendAmt) {
Constant *ShAmt = ConstantInt::get(I.getType(), ExtendAmt);
Value *NewShl = Builder->CreateShl(XorLHS, ShAmt, "sext");
@@ -148,23 +139,23 @@
}
}
+ if (isa<Constant>(RHS) && isa<PHINode>(LHS))
+ if (Instruction *NV = FoldOpIntoPhi(I))
+ return NV;
+
if (I.getType()->isIntegerTy(1))
return BinaryOperator::CreateXor(LHS, RHS);
- if (I.getType()->isIntegerTy()) {
- // X + X --> X << 1
- if (LHS == RHS)
- return BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
- }
+ // X + X --> X << 1
+ if (LHS == RHS && I.getType()->isIntegerTy())
+ return BinaryOperator::CreateShl(LHS, ConstantInt::get(I.getType(), 1));
// -A + B --> B - A
// -A + -B --> -(A + B)
if (Value *LHSV = dyn_castNegVal(LHS)) {
- if (LHS->getType()->isIntOrIntVectorTy()) {
- if (Value *RHSV = dyn_castNegVal(RHS)) {
- Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
- return BinaryOperator::CreateNeg(NewAdd);
- }
+ if (Value *RHSV = dyn_castNegVal(RHS)) {
+ Value *NewAdd = Builder->CreateAdd(LHSV, RHSV, "sum");
+ return BinaryOperator::CreateNeg(NewAdd);
}
return BinaryOperator::CreateSub(RHS, LHSV);
@@ -209,7 +200,7 @@
}
// W*X + Y*Z --> W * (X+Z) iff W == Y
- if (I.getType()->isIntOrIntVectorTy()) {
+ {
Value *W, *X, *Y, *Z;
if (match(LHS, m_Mul(m_Value(W), m_Value(X))) &&
match(RHS, m_Mul(m_Value(Y), m_Value(Z)))) {
@@ -238,24 +229,22 @@
// (X & FF00) + xx00 -> (X+xx00) & FF00
if (LHS->hasOneUse() &&
- match(LHS, m_And(m_Value(X), m_ConstantInt(C2)))) {
- Constant *Anded = ConstantExpr::getAnd(CRHS, C2);
- if (Anded == CRHS) {
- // See if all bits from the first bit set in the Add RHS up are included
- // in the mask. First, get the rightmost bit.
- const APInt &AddRHSV = CRHS->getValue();
-
- // Form a mask of all bits from the lowest bit added through the top.
- APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));
-
- // See if the and mask includes all of these bits.
- APInt AddRHSHighBitsAnd(AddRHSHighBits & C2->getValue());
-
- if (AddRHSHighBits == AddRHSHighBitsAnd) {
- // Okay, the xform is safe. Insert the new add pronto.
- Value *NewAdd = Builder->CreateAdd(X, CRHS, LHS->getName());
- return BinaryOperator::CreateAnd(NewAdd, C2);
- }
+ match(LHS, m_And(m_Value(X), m_ConstantInt(C2))) &&
+ CRHS->getValue() == (CRHS->getValue() & C2->getValue())) {
+ // See if all bits from the first bit set in the Add RHS up are included
+ // in the mask. First, get the rightmost bit.
+ const APInt &AddRHSV = CRHS->getValue();
+
+ // Form a mask of all bits from the lowest bit added through the top.
+ APInt AddRHSHighBits(~((AddRHSV & -AddRHSV)-1));
+
+ // See if the and mask includes all of these bits.
+ APInt AddRHSHighBitsAnd(AddRHSHighBits & C2->getValue());
+
+ if (AddRHSHighBits == AddRHSHighBitsAnd) {
+ // Okay, the xform is safe. Insert the new add pronto.
+ Value *NewAdd = Builder->CreateAdd(X, CRHS, LHS->getName());
+ return BinaryOperator::CreateAnd(NewAdd, C2);
}
}
@@ -280,12 +269,11 @@
// Can we fold the add into the argument of the select?
// We check both true and false select arguments for a matching subtract.
- if (match(FV, m_Zero()) &&
- match(TV, m_Sub(m_Value(N), m_Specific(A))))
+ if (match(FV, m_Zero()) && match(TV, m_Sub(m_Value(N), m_Specific(A))))
// Fold the add into the true select value.
return SelectInst::Create(SI->getCondition(), N, A);
- if (match(TV, m_Zero()) &&
- match(FV, m_Sub(m_Value(N), m_Specific(A))))
+
+ if (match(TV, m_Zero()) && match(FV, m_Sub(m_Value(N), m_Specific(A))))
// Fold the add into the false select value.
return SelectInst::Create(SI->getCondition(), A, N);
}
@@ -550,12 +538,12 @@
if (I.getType()->isIntegerTy(1))
return BinaryOperator::CreateXor(Op0, Op1);
+
+ // Replace (-1 - A) with (~A).
+ if (match(Op0, m_AllOnes()))
+ return BinaryOperator::CreateNot(Op1);
if (ConstantInt *C = dyn_cast<ConstantInt>(Op0)) {
- // Replace (-1 - A) with (~A).
- if (C->isAllOnesValue())
- return BinaryOperator::CreateNot(Op1);
-
// C - ~X == X + (1+C)
Value *X = 0;
if (match(Op1, m_Not(m_Value(X))))
@@ -564,29 +552,16 @@
// -(X >>u 31) -> (X >>s 31)
// -(X >>s 31) -> (X >>u 31)
if (C->isZero()) {
- if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op1)) {
- if (SI->getOpcode() == Instruction::LShr) {
- if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
- // Check to see if we are shifting out everything but the sign bit.
- if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
- SI->getType()->getPrimitiveSizeInBits()-1) {
- // Ok, the transformation is safe. Insert AShr.
- return BinaryOperator::Create(Instruction::AShr,
- SI->getOperand(0), CU, SI->getName());
- }
- }
- } else if (SI->getOpcode() == Instruction::AShr) {
- if (ConstantInt *CU = dyn_cast<ConstantInt>(SI->getOperand(1))) {
- // Check to see if we are shifting out everything but the sign bit.
- if (CU->getLimitedValue(SI->getType()->getPrimitiveSizeInBits()) ==
- SI->getType()->getPrimitiveSizeInBits()-1) {
- // Ok, the transformation is safe. Insert LShr.
- return BinaryOperator::CreateLShr(
- SI->getOperand(0), CU, SI->getName());
- }
- }
- }
- }
+ Value *X; ConstantInt *CI;
+ if (match(Op1, m_LShr(m_Value(X), m_ConstantInt(CI))) &&
+ // Verify we are shifting out everything but the sign bit.
+ CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
+ return BinaryOperator::CreateAShr(X, CI);
+
+ if (match(Op1, m_AShr(m_Value(X), m_ConstantInt(CI))) &&
+ // Verify we are shifting out everything but the sign bit.
+ CI->getValue() == I.getType()->getPrimitiveSizeInBits()-1)
+ return BinaryOperator::CreateLShr(X, CI);
}
// Try to fold constant sub into select arguments.
@@ -596,99 +571,80 @@
// C - zext(bool) -> bool ? C - 1 : C
if (ZExtInst *ZI = dyn_cast<ZExtInst>(Op1))
- if (ZI->getSrcTy() == Type::getInt1Ty(I.getContext()))
+ if (ZI->getSrcTy()->isIntegerTy(1))
return SelectInst::Create(ZI->getOperand(0), SubOne(C), C);
- }
- if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) {
- if (Op1I->getOpcode() == Instruction::Add) {
- if (Op1I->getOperand(0) == Op0) // X-(X+Y) == -Y
- return BinaryOperator::CreateNeg(Op1I->getOperand(1),
- I.getName());
- else if (Op1I->getOperand(1) == Op0) // X-(Y+X) == -Y
- return BinaryOperator::CreateNeg(Op1I->getOperand(0),
- I.getName());
- else if (ConstantInt *CI1 = dyn_cast<ConstantInt>(I.getOperand(0))) {
- if (ConstantInt *CI2 = dyn_cast<ConstantInt>(Op1I->getOperand(1)))
- // C1-(X+C2) --> (C1-C2)-X
- return BinaryOperator::CreateSub(
- ConstantExpr::getSub(CI1, CI2), Op1I->getOperand(0));
- }
- }
-
- if (Op1I->hasOneUse()) {
- // Replace (x - (y - z)) with (x + (z - y)) if the (y - z) subexpression
- // is not used by anyone else...
- //
- if (Op1I->getOpcode() == Instruction::Sub) {
- // Swap the two operands of the subexpr...
- Value *IIOp0 = Op1I->getOperand(0), *IIOp1 = Op1I->getOperand(1);
- Op1I->setOperand(0, IIOp1);
- Op1I->setOperand(1, IIOp0);
-
- // Create the new top level add instruction...
- return BinaryOperator::CreateAdd(Op0, Op1);
- }
-
- // Replace (A - (A & B)) with (A & ~B) if this is the only use of (A&B)...
- //
- if (Op1I->getOpcode() == Instruction::And &&
- (Op1I->getOperand(0) == Op0 || Op1I->getOperand(1) == Op0)) {
- Value *OtherOp = Op1I->getOperand(Op1I->getOperand(0) == Op0);
-
- Value *NewNot = Builder->CreateNot(OtherOp, "B.not");
- return BinaryOperator::CreateAnd(Op0, NewNot);
- }
-
- // 0 - (X sdiv C) -> (X sdiv -C)
- if (Op1I->getOpcode() == Instruction::SDiv)
- if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
- if (CSI->isZero())
- if (Constant *DivRHS = dyn_cast<Constant>(Op1I->getOperand(1)))
- return BinaryOperator::CreateSDiv(Op1I->getOperand(0),
- ConstantExpr::getNeg(DivRHS));
-
- // 0 - (C << X) -> (-C << X)
- if (Op1I->getOpcode() == Instruction::Shl)
- if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
- if (CSI->isZero())
- if (Value *ShlLHSNeg = dyn_castNegVal(Op1I->getOperand(0)))
- return BinaryOperator::CreateShl(ShlLHSNeg, Op1I->getOperand(1));
-
- // X - X*C --> X * (1-C)
- ConstantInt *C2 = 0;
- if (dyn_castFoldableMul(Op1I, C2) == Op0) {
- Constant *CP1 =
- ConstantExpr::getSub(ConstantInt::get(I.getType(), 1),
- C2);
- return BinaryOperator::CreateMul(Op0, CP1);
- }
-
- // X - A*-B -> X + A*B
- // X - -A*B -> X + A*B
- Value *A, *B;
- if (match(Op1I, m_Mul(m_Value(A), m_Neg(m_Value(B)))) ||
- match(Op1I, m_Mul(m_Neg(m_Value(A)), m_Value(B)))) {
- Value *NewMul = Builder->CreateMul(A, B);
- return BinaryOperator::CreateAdd(Op0, NewMul);
- }
-
- // X - A*Cst -> X + A*-Cst
- // X - Cst*A -> X + A*-Cst
- ConstantInt *BCst;
- if (match(Op1I, m_Mul(m_Value(A), m_ConstantInt(BCst))) ||
- match(Op1I, m_Mul(m_ConstantInt(BCst), m_Value(A)))) {
- Value *NewMul = Builder->CreateMul(A, ConstantExpr::getNeg(BCst));
- return BinaryOperator::CreateAdd(Op0, NewMul);
- }
- }
+ // C-(X+C2) --> (C-C2)-X
+ ConstantInt *C2;
+ if (match(Op1, m_Add(m_Value(X), m_ConstantInt(C2))))
+ return BinaryOperator::CreateSub(ConstantExpr::getSub(C, C2), X);
}
- if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) {
- if (Op0I->getOpcode() == Instruction::Sub) {
- if (Op0I->getOperand(0) == Op1) // (X-Y)-X == -Y
- return BinaryOperator::CreateNeg(Op0I->getOperand(1),
- I.getName());
+
+ { Value *Y;
+ // X-(X+Y) == -Y X-(Y+X) == -Y
+ if (match(Op1, m_Add(m_Specific(Op0), m_Value(Y))) ||
+ match(Op1, m_Add(m_Value(Y), m_Specific(Op0))))
+ return BinaryOperator::CreateNeg(Y);
+
+ // (X-Y)-X == -Y
+ if (match(Op0, m_Sub(m_Specific(Op1), m_Value(Y))))
+ return BinaryOperator::CreateNeg(Y);
+ }
+
+ if (Op1->hasOneUse()) {
+ Value *X = 0, *Y = 0, *Z = 0;
+ Constant *C = 0;
+ ConstantInt *CI = 0;
+
+ // (X - (Y - Z)) --> (X + (Z - Y)).
+ if (match(Op1, m_Sub(m_Value(Y), m_Value(Z))))
+ return BinaryOperator::CreateAdd(Op0,
+ Builder->CreateSub(Z, Y, Op1->getName()));
+
+ // (X - (X & Y)) --> (X & ~Y)
+ //
+ if (match(Op1, m_And(m_Value(Y), m_Specific(Op0))) ||
+ match(Op1, m_And(m_Specific(Op0), m_Value(Y))))
+ return BinaryOperator::CreateAnd(Op0,
+ Builder->CreateNot(Y, Y->getName() + ".not"));
+
+ // 0 - (X sdiv C) -> (X sdiv -C)
+ if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) &&
+ match(Op0, m_Zero()))
+ return BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));
+
+ // 0 - (X << Y) -> (-X << Y) when X is freely negatable.
+ if (match(Op1, m_Shl(m_Value(X), m_Value(Y))) && match(Op0, m_Zero()))
+ if (Value *XNeg = dyn_castNegVal(X))
+ return BinaryOperator::CreateShl(XNeg, Y);
+
+ // X - X*C --> X * (1-C)
+ if (match(Op1, m_Mul(m_Specific(Op0), m_ConstantInt(CI)))) {
+ Constant *CP1 = ConstantExpr::getSub(ConstantInt::get(I.getType(),1), CI);
+ return BinaryOperator::CreateMul(Op0, CP1);
+ }
+
+ // X - X<<C --> X * (1-(1<<C))
+ if (match(Op1, m_Shl(m_Specific(Op0), m_ConstantInt(CI)))) {
+ Constant *One = ConstantInt::get(I.getType(), 1);
+ C = ConstantExpr::getSub(One, ConstantExpr::getShl(One, CI));
+ return BinaryOperator::CreateMul(Op0, C);
+ }
+
+ // X - A*-B -> X + A*B
+ // X - -A*B -> X + A*B
+ Value *A, *B;
+ if (match(Op1, m_Mul(m_Value(A), m_Neg(m_Value(B)))) ||
+ match(Op1, m_Mul(m_Neg(m_Value(A)), m_Value(B))))
+ return BinaryOperator::CreateAdd(Op0, Builder->CreateMul(A, B));
+
+ // X - A*CI -> X + A*-CI
+ // X - CI*A -> X + A*-CI
+ if (match(Op1, m_Mul(m_Value(A), m_ConstantInt(CI))) ||
+ match(Op1, m_Mul(m_ConstantInt(CI), m_Value(A)))) {
+ Value *NewMul = Builder->CreateMul(A, ConstantExpr::getNeg(CI));
+ return BinaryOperator::CreateAdd(Op0, NewMul);
}
}
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