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[SCEV] Simplify some flags expressions.

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Summary:
Sending for presubmit review out of an abundance of caution; it would be
bad to mess this up.

Reviewers: sanjoy

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D48238

llvm-svn: 334875
This commit is contained in:
Justin Lebar 2018-06-15 23:52:11 +00:00
parent 981d01ddf8
commit 91fb960d92
1 changed files with 4 additions and 4 deletions
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8
lib/Analysis/ScalarEvolution.cpp
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@ -3897,7 +3897,7 @@ const SCEV *ScalarEvolution::getMinusSCEV(const SCEV *LHS, const SCEV *RHS,
auto AddFlags = SCEV::FlagAnyWrap;
const bool RHSIsNotMinSigned =
!getSignedRangeMin(RHS).isMinSignedValue();
if ((Flags & SCEV::FlagNSW) == SCEV::FlagNSW) {
if (Flags & SCEV::FlagNSW) {
// Let M be the minimum representable signed value. Then (-1)*RHS
// signed-wraps if and only if RHS is M. That can happen even for
// a NSW subtraction because e.g. (-1)*M signed-wraps even though
@ -11940,7 +11940,7 @@ bool SCEVWrapPredicate::isAlwaysTrue() const {
SCEV::NoWrapFlags ScevFlags = AR->getNoWrapFlags();
IncrementWrapFlags IFlags = Flags;
if ((ScevFlags | SCEV::FlagNSW) == ScevFlags)
if (ScevFlags & SCEV::FlagNSW)
IFlags &= ~IncrementNSSW;
return IFlags == IncrementAnyWrap;
@ -11962,10 +11962,10 @@ SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR,
SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags();
// We can safely transfer the NSW flag as NSSW.
if ((StaticFlags | SCEV::FlagNSW) == StaticFlags)
if (StaticFlags & SCEV::FlagNSW)
ImpliedFlags = IncrementNSSW;
if ((StaticFlags | SCEV::FlagNUW) == StaticFlags) {
if (StaticFlags & SCEV::FlagNUW) {
// If the increment is positive, the SCEV NUW flag will also imply the
// WrapPredicate NUSW flag.
if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))