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[LFTR] Stylistic cleanup as suggested in last review comment of D62939 [NFC]

(Resumbit of r363292 which was reverted along w/an earlier patch)

llvm-svn: 363877
This commit is contained in:
Philip Reames 2019-06-19 20:45:57 +00:00
parent 495c7b3f90
commit 54a13158b2

View File

@ -2388,12 +2388,15 @@ bool IndVarSimplify::
linearFunctionTestReplace(Loop *L, BasicBlock *ExitingBB,
const SCEV *ExitCount,
PHINode *IndVar, SCEVExpander &Rewriter) {
assert(L->getLoopLatch() && "Loop no longer in simplified form?");
assert(isLoopCounter(IndVar, L, SE));
Instruction * const IncVar =
cast<Instruction>(IndVar->getIncomingValueForBlock(L->getLoopLatch()));
// Initialize CmpIndVar and IVCount to their preincremented values.
Value *CmpIndVar = IndVar;
const SCEV *IVCount = ExitCount;
assert(L->getLoopLatch() && "Loop no longer in simplified form?");
// If the exiting block is the same as the backedge block, we prefer to
// compare against the post-incremented value, otherwise we must compare
// against the preincremented value.
@ -2404,14 +2407,12 @@ linearFunctionTestReplace(Loop *L, BasicBlock *ExitingBB,
// to add a potentially UB introducing use. We need to either a) show
// the loop test we're modifying is already in post-inc form, or b) show
// that adding a use must not introduce UB.
Instruction *Inc =
cast<Instruction>(IndVar->getIncomingValueForBlock(L->getLoopLatch()));
if (ICmpInst *LoopTest = getLoopTest(L, ExitingBB))
SafeToPostInc = LoopTest->getOperand(0) == Inc ||
LoopTest->getOperand(1) == Inc;
SafeToPostInc = LoopTest->getOperand(0) == IncVar ||
LoopTest->getOperand(1) == IncVar;
if (!SafeToPostInc)
SafeToPostInc =
mustExecuteUBIfPoisonOnPathTo(Inc, ExitingBB->getTerminator(), DT);
mustExecuteUBIfPoisonOnPathTo(IncVar, ExitingBB->getTerminator(), DT);
}
if (SafeToPostInc) {
// Add one to the "backedge-taken" count to get the trip count.
@ -2422,7 +2423,7 @@ linearFunctionTestReplace(Loop *L, BasicBlock *ExitingBB,
// The BackedgeTaken expression contains the number of times that the
// backedge branches to the loop header. This is one less than the
// number of times the loop executes, so use the incremented indvar.
CmpIndVar = IndVar->getIncomingValueForBlock(ExitingBB);
CmpIndVar = IncVar;
}
}
@ -2438,7 +2439,6 @@ linearFunctionTestReplace(Loop *L, BasicBlock *ExitingBB,
// dynamically dead IV that wraps on the first loop iteration only, which is
// not covered by the post-inc addrec. (If the new IV was not dynamically
// dead, it could not be poison on the first iteration in the first place.)
Value *IncVar = IndVar->getIncomingValueForBlock(L->getLoopLatch());
if (auto *BO = dyn_cast<BinaryOperator>(IncVar)) {
const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(SE->getSCEV(IncVar));
if (BO->hasNoUnsignedWrap())