diff options
Diffstat (limited to 'llvm/lib/Analysis/ScalarEvolution.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 3fab6b0..a64b93d 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -6417,8 +6417,18 @@ APInt ScalarEvolution::getConstantMultipleImpl(const SCEV *S, case scSequentialUMinExpr: return GetGCDMultiple(cast<SCEVNAryExpr>(S)); case scUnknown: { - // ask ValueTracking for known bits + // Ask ValueTracking for known bits. SCEVUnknown only become available at + // the point their underlying IR instruction has been defined. If CtxI was + // not provided, use: + // * the first instruction in the entry block if it is an argument + // * the instruction itself otherwise. const SCEVUnknown *U = cast<SCEVUnknown>(S); + if (!CtxI) { + if (isa<Argument>(U->getValue())) + CtxI = &*F.getEntryBlock().begin(); + else if (auto *I = dyn_cast<Instruction>(U->getValue())) + CtxI = I; + } unsigned Known = computeKnownBits(U->getValue(), getDataLayout(), &AC, CtxI, &DT) .countMinTrailingZeros(); @@ -15761,6 +15771,21 @@ void ScalarEvolution::LoopGuards::collectFromBlock( const SCEV *OneAlignedUp = GetNextSCEVDividesByDivisor(One, DividesBy); To = SE.getUMaxExpr(FromRewritten, OneAlignedUp); + } else { + if (LHS->getType()->isPointerTy()) { + LHS = SE.getLosslessPtrToIntExpr(LHS); + RHS = SE.getLosslessPtrToIntExpr(RHS); + if (isa<SCEVCouldNotCompute>(LHS) || isa<SCEVCouldNotCompute>(RHS)) + break; + } + auto AddSubRewrite = [&](const SCEV *A, const SCEV *B) { + const SCEV *Sub = SE.getMinusSCEV(A, B); + AddRewrite(Sub, Sub, + SE.getUMaxExpr(Sub, SE.getOne(From->getType()))); + }; + AddSubRewrite(LHS, RHS); + AddSubRewrite(RHS, LHS); + continue; } break; default: |