diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Analysis/ScalarEvolution.cpp | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index a6fa842..9e48143 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -5693,8 +5693,16 @@ getRangeForUnknownRecurrence(const SCEVUnknown *U) { // until the caller issue can be fixed. PR49566 tracks the bug. return CR; - // TODO: Handle ashr and lshr cases to increase minimum value reported - if (BO->getOpcode() != Instruction::Shl || BO->getOperand(0) != P) + // TODO: Extend to other opcodes such as ashr, mul, and div + switch (BO->getOpcode()) { + default: + return CR; + case Instruction::Shl: + break; + }; + + if (BO->getOperand(0) != P) + // TODO: Handle the power function forms some day. return CR; unsigned TC = getSmallConstantMaxTripCount(L); @@ -5714,12 +5722,19 @@ getRangeForUnknownRecurrence(const SCEVUnknown *U) { if (Overflow) return CR; - // Iff no bits are shifted out, value increases on every shift. - auto KnownEnd = KnownBits::shl(KnownStart, - KnownBits::makeConstant(TotalShift)); - if (TotalShift.ult(KnownStart.countMinLeadingZeros())) - CR = CR.intersectWith(ConstantRange(KnownStart.getMinValue(), - KnownEnd.getMaxValue() + 1)); + switch (BO->getOpcode()) { + default: + llvm_unreachable("filtered out above"); + case Instruction::Shl: { + // Iff no bits are shifted out, value increases on every shift. + auto KnownEnd = KnownBits::shl(KnownStart, + KnownBits::makeConstant(TotalShift)); + if (TotalShift.ult(KnownStart.countMinLeadingZeros())) + CR = CR.intersectWith(ConstantRange(KnownStart.getMinValue(), + KnownEnd.getMaxValue() + 1)); + break; + } + }; return CR; } |