diff options
Diffstat (limited to 'llvm/lib/Analysis/ScalarEvolution.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index af366aba1bb..c820464c1da 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -5504,17 +5504,16 @@ ScalarEvolution::getSmallConstantTripMultiple(const Loop *L, return 1; // Get the trip count from the BE count by adding 1. - const SCEV *TCMul = getAddExpr(ExitCount, getOne(ExitCount->getType())); - // FIXME: SCEV distributes multiplication as V1*C1 + V2*C1. We could attempt - // to factor simple cases. - if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(TCMul)) - TCMul = Mul->getOperand(0); - - const SCEVConstant *MulC = dyn_cast<SCEVConstant>(TCMul); - if (!MulC) - return 1; + const SCEV *TCExpr = getAddExpr(ExitCount, getOne(ExitCount->getType())); + + const SCEVConstant *TC = dyn_cast<SCEVConstant>(TCExpr); + if (!TC) + // Attempt to factor more general cases. Returns the greatest power of + // two divisor. If overflow happens, the trip count expression is still + // divisible by the greatest power of 2 divisor returned. + return 1U << std::min((uint32_t)31, GetMinTrailingZeros(TCExpr)); - ConstantInt *Result = MulC->getValue(); + ConstantInt *Result = TC->getValue(); // Guard against huge trip counts (this requires checking // for zero to handle the case where the trip count == -1 and the @@ -9667,6 +9666,13 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE, OS << "Unpredictable predicated backedge-taken count. "; } OS << "\n"; + + if (SE->hasLoopInvariantBackedgeTakenCount(L)) { + OS << "Loop "; + L->getHeader()->printAsOperand(OS, /*PrintType=*/false); + OS << ": "; + OS << "Trip multiple is " << SE->getSmallConstantTripMultiple(L) << "\n"; + } } static StringRef loopDispositionToStr(ScalarEvolution::LoopDisposition LD) { |
