diff options
Diffstat (limited to 'contrib/llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/ValueTracking.cpp | 76 |
1 files changed, 55 insertions, 21 deletions
diff --git a/contrib/llvm/lib/Analysis/ValueTracking.cpp b/contrib/llvm/lib/Analysis/ValueTracking.cpp index d31472c0d33c..b79370baad10 100644 --- a/contrib/llvm/lib/Analysis/ValueTracking.cpp +++ b/contrib/llvm/lib/Analysis/ValueTracking.cpp @@ -526,7 +526,10 @@ static void computeKnownBitsFromAssume(const Value *V, APInt &KnownZero, unsigned BitWidth = KnownZero.getBitWidth(); - for (auto &AssumeVH : Q.AC->assumptions()) { + // Note that the patterns below need to be kept in sync with the code + // in AssumptionCache::updateAffectedValues. + + for (auto &AssumeVH : Q.AC->assumptionsFor(V)) { if (!AssumeVH) continue; CallInst *I = cast<CallInst>(AssumeVH); @@ -2580,51 +2583,70 @@ bool llvm::CannotBeNegativeZero(const Value *V, const TargetLibraryInfo *TLI, return false; } -bool llvm::CannotBeOrderedLessThanZero(const Value *V, - const TargetLibraryInfo *TLI, - unsigned Depth) { - if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V)) - return !CFP->getValueAPF().isNegative() || CFP->getValueAPF().isZero(); +/// If \p SignBitOnly is true, test for a known 0 sign bit rather than a +/// standard ordered compare. e.g. make -0.0 olt 0.0 be true because of the sign +/// bit despite comparing equal. +static bool cannotBeOrderedLessThanZeroImpl(const Value *V, + const TargetLibraryInfo *TLI, + bool SignBitOnly, + unsigned Depth) { + if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V)) { + return !CFP->getValueAPF().isNegative() || + (!SignBitOnly && CFP->getValueAPF().isZero()); + } if (Depth == MaxDepth) - return false; // Limit search depth. + return false; // Limit search depth. const Operator *I = dyn_cast<Operator>(V); - if (!I) return false; + if (!I) + return false; switch (I->getOpcode()) { - default: break; + default: + break; // Unsigned integers are always nonnegative. case Instruction::UIToFP: return true; case Instruction::FMul: // x*x is always non-negative or a NaN. - if (I->getOperand(0) == I->getOperand(1)) + if (I->getOperand(0) == I->getOperand(1) && + (!SignBitOnly || cast<FPMathOperator>(I)->hasNoNaNs())) return true; + LLVM_FALLTHROUGH; case Instruction::FAdd: case Instruction::FDiv: case Instruction::FRem: - return CannotBeOrderedLessThanZero(I->getOperand(0), TLI, Depth + 1) && - CannotBeOrderedLessThanZero(I->getOperand(1), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, + Depth + 1) && + cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly, + Depth + 1); case Instruction::Select: - return CannotBeOrderedLessThanZero(I->getOperand(1), TLI, Depth + 1) && - CannotBeOrderedLessThanZero(I->getOperand(2), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly, + Depth + 1) && + cannotBeOrderedLessThanZeroImpl(I->getOperand(2), TLI, SignBitOnly, + Depth + 1); case Instruction::FPExt: case Instruction::FPTrunc: // Widening/narrowing never change sign. - return CannotBeOrderedLessThanZero(I->getOperand(0), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, + Depth + 1); case Instruction::Call: Intrinsic::ID IID = getIntrinsicForCallSite(cast<CallInst>(I), TLI); switch (IID) { default: break; case Intrinsic::maxnum: - return CannotBeOrderedLessThanZero(I->getOperand(0), TLI, Depth + 1) || - CannotBeOrderedLessThanZero(I->getOperand(1), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, + Depth + 1) || + cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly, + Depth + 1); case Intrinsic::minnum: - return CannotBeOrderedLessThanZero(I->getOperand(0), TLI, Depth + 1) && - CannotBeOrderedLessThanZero(I->getOperand(1), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, + Depth + 1) && + cannotBeOrderedLessThanZeroImpl(I->getOperand(1), TLI, SignBitOnly, + Depth + 1); case Intrinsic::exp: case Intrinsic::exp2: case Intrinsic::fabs: @@ -2636,18 +2658,30 @@ bool llvm::CannotBeOrderedLessThanZero(const Value *V, if (CI->getBitWidth() <= 64 && CI->getSExtValue() % 2u == 0) return true; } - return CannotBeOrderedLessThanZero(I->getOperand(0), TLI, Depth + 1); + return cannotBeOrderedLessThanZeroImpl(I->getOperand(0), TLI, SignBitOnly, + Depth + 1); case Intrinsic::fma: case Intrinsic::fmuladd: // x*x+y is non-negative if y is non-negative. return I->getOperand(0) == I->getOperand(1) && - CannotBeOrderedLessThanZero(I->getOperand(2), TLI, Depth + 1); + (!SignBitOnly || cast<FPMathOperator>(I)->hasNoNaNs()) && + cannotBeOrderedLessThanZeroImpl(I->getOperand(2), TLI, SignBitOnly, + Depth + 1); } break; } return false; } +bool llvm::CannotBeOrderedLessThanZero(const Value *V, + const TargetLibraryInfo *TLI) { + return cannotBeOrderedLessThanZeroImpl(V, TLI, false, 0); +} + +bool llvm::SignBitMustBeZero(const Value *V, const TargetLibraryInfo *TLI) { + return cannotBeOrderedLessThanZeroImpl(V, TLI, true, 0); +} + /// If the specified value can be set by repeating the same byte in memory, /// return the i8 value that it is represented with. This is /// true for all i8 values obviously, but is also true for i32 0, i32 -1, |