From dba8b4c04d579b946572800d20419e70177b3194 Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Thu, 2 Jun 2016 20:01:37 +0000 Subject: transform obscured FP sign bit ops into a fabs/fneg using TLI hook This is effectively a revert of: http://reviews.llvm.org/rL249702 - [InstCombine] transform masking off of an FP sign bit into a fabs() intrinsic call (PR24886) and: http://reviews.llvm.org/rL249701 - [ValueTracking] teach computeKnownBits that a fabs() clears sign bits and a reimplementation as a DAG combine for targets that have IEEE754-compliant fabs/fneg instructions. This is intended to resolve the objections raised on the dev list: http://lists.llvm.org/pipermail/llvm-dev/2016-April/098154.html and: https://llvm.org/bugs/show_bug.cgi?id=24886#c4 In the interest of patch minimalism, I've only partly enabled AArch64. PowerPC, MIPS, x86 and others can enable later. Differential Revision: http://reviews.llvm.org/D19391 llvm-svn: 271573 --- llvm/lib/Analysis/ValueTracking.cpp | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) (limited to 'llvm/lib/Analysis/ValueTracking.cpp') diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 761b8332ec4..c7f662140d4 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -991,8 +991,7 @@ static void computeKnownBitsFromOperator(Operator *I, APInt &KnownZero, } case Instruction::BitCast: { Type *SrcTy = I->getOperand(0)->getType(); - if ((SrcTy->isIntegerTy() || SrcTy->isPointerTy() || - SrcTy->isFloatingPointTy()) && + if ((SrcTy->isIntegerTy() || SrcTy->isPointerTy()) && // TODO: For now, not handling conversions like: // (bitcast i64 %x to <2 x i32>) !I->getType()->isVectorTy()) { @@ -1316,12 +1315,6 @@ static void computeKnownBitsFromOperator(Operator *I, APInt &KnownZero, // of bits which might be set provided by popcnt KnownOne2. break; } - case Intrinsic::fabs: { - Type *Ty = II->getType(); - APInt SignBit = APInt::getSignBit(Ty->getScalarSizeInBits()); - KnownZero |= APInt::getSplat(Ty->getPrimitiveSizeInBits(), SignBit); - break; - } case Intrinsic::x86_sse42_crc32_64_64: KnownZero |= APInt::getHighBitsSet(64, 32); break; @@ -1381,9 +1374,8 @@ void computeKnownBits(Value *V, APInt &KnownZero, APInt &KnownOne, unsigned BitWidth = KnownZero.getBitWidth(); assert((V->getType()->isIntOrIntVectorTy() || - V->getType()->isFPOrFPVectorTy() || V->getType()->getScalarType()->isPointerTy()) && - "Not integer, floating point, or pointer type!"); + "Not integer or pointer type!"); assert((Q.DL.getTypeSizeInBits(V->getType()->getScalarType()) == BitWidth) && (!V->getType()->isIntOrIntVectorTy() || V->getType()->getScalarSizeInBits() == BitWidth) && -- cgit v1.2.3