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[ValueTracking][InstCombine] Use m_Shr instead m_CombineOr(m_LShr, m_AShr). NFC 

llvm-svn: 306205
This commit is contained in:
Craig Topper 2017-06-24 06:24:04 +00:00
parent 72ee6945af
commit 7b66ffe875
2 changed files with 3 additions and 7 deletions
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7
llvm/lib/Analysis/ValueTracking.cpp
View File

@ -686,8 +686,7 @@ static void computeKnownBitsFromAssume(const Value *V, KnownBits &Known,
Known.One |= RHSKnown.Zero;
// assume(v >> c = a)
} else if (match(Arg,
m_c_ICmp(Pred, m_CombineOr(m_LShr(m_V, m_ConstantInt(C)),
m_AShr(m_V, m_ConstantInt(C))),
m_c_ICmp(Pred, m_Shr(m_V, m_ConstantInt(C)),
m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ &&
isValidAssumeForContext(I, Q.CxtI, Q.DT)) {
@ -698,9 +697,7 @@ static void computeKnownBitsFromAssume(const Value *V, KnownBits &Known,
Known.Zero |= RHSKnown.Zero << C->getZExtValue();
Known.One |= RHSKnown.One << C->getZExtValue();
// assume(~(v >> c) = a)
} else if (match(Arg, m_c_ICmp(Pred, m_Not(m_CombineOr(
m_LShr(m_V, m_ConstantInt(C)),
m_AShr(m_V, m_ConstantInt(C)))),
} else if (match(Arg, m_c_ICmp(Pred, m_Not(m_Shr(m_V, m_ConstantInt(C))),
m_Value(A))) &&
Pred == ICmpInst::ICMP_EQ &&
isValidAssumeForContext(I, Q.CxtI, Q.DT)) {

3
llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
View File

@ -556,8 +556,7 @@ Instruction *InstCombiner::visitShl(BinaryOperator &I) {
// The inexact versions are deferred to DAGCombine, so we don't hide shl
// behind a bit mask.
const APInt *ShOp1;
if (match(Op0, m_CombineOr(m_Exact(m_LShr(m_Value(X), m_APInt(ShOp1))),
m_Exact(m_AShr(m_Value(X), m_APInt(ShOp1)))))) {
if (match(Op0, m_Exact(m_Shr(m_Value(X), m_APInt(ShOp1))))) {
unsigned ShrAmt = ShOp1->getZExtValue();
if (ShrAmt < ShAmt) {
// If C1 < C2: (X >>?,exact C1) << C2 --> X << (C2 - C1)