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author | Rafael Espindola <rafael.espindola@gmail.com> | 2012-04-04 12:51:34 +0000 |
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committer | Rafael Espindola <rafael.espindola@gmail.com> | 2012-04-04 12:51:34 +0000 |
commit | 26c8dcc692fb2addd475446cfff24d6a4e958bca (patch) | |
tree | b71cb0d781e2735397c728f276f14ea63780d04c /lib/Analysis/ScalarEvolution.cpp | |
parent | 00b73a5e443d49d68f59a5fb517e940842423ae6 (diff) | |
download | llvm-26c8dcc692fb2addd475446cfff24d6a4e958bca.tar.gz llvm-26c8dcc692fb2addd475446cfff24d6a4e958bca.tar.bz2 llvm-26c8dcc692fb2addd475446cfff24d6a4e958bca.tar.xz |
Always compute all the bits in ComputeMaskedBits.
This allows us to keep passing reduced masks to SimplifyDemandedBits, but
know about all the bits if SimplifyDemandedBits fails. This allows instcombine
to simplify cases like the one in the included testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154011 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ScalarEvolution.cpp')
-rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 8b5397946e..205227ca0b 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -3261,9 +3261,8 @@ ScalarEvolution::GetMinTrailingZeros(const SCEV *S) { if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { // For a SCEVUnknown, ask ValueTracking. unsigned BitWidth = getTypeSizeInBits(U->getType()); - APInt Mask = APInt::getAllOnesValue(BitWidth); APInt Zeros(BitWidth, 0), Ones(BitWidth, 0); - ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones); + ComputeMaskedBits(U->getValue(), Zeros, Ones); return Zeros.countTrailingOnes(); } @@ -3401,9 +3400,8 @@ ScalarEvolution::getUnsignedRange(const SCEV *S) { if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) { // For a SCEVUnknown, ask ValueTracking. - APInt Mask = APInt::getAllOnesValue(BitWidth); APInt Zeros(BitWidth, 0), Ones(BitWidth, 0); - ComputeMaskedBits(U->getValue(), Mask, Zeros, Ones, TD); + ComputeMaskedBits(U->getValue(), Zeros, Ones, TD); if (Ones == ~Zeros + 1) return setUnsignedRange(U, ConservativeResult); return setUnsignedRange(U, @@ -3660,9 +3658,8 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) { // knew about to reconstruct a low-bits mask value. unsigned LZ = A.countLeadingZeros(); unsigned BitWidth = A.getBitWidth(); - APInt AllOnes = APInt::getAllOnesValue(BitWidth); APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0); - ComputeMaskedBits(U->getOperand(0), AllOnes, KnownZero, KnownOne, TD); + ComputeMaskedBits(U->getOperand(0), KnownZero, KnownOne, TD); APInt EffectiveMask = APInt::getLowBitsSet(BitWidth, BitWidth - LZ); |