diff options
Diffstat (limited to 'lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index ef19e065b7..4739d1b881 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -1912,11 +1912,31 @@ bool llvm::isSafeToSpeculativelyExecute(const Instruction *Inst, return false; return LI->getPointerOperand()->isDereferenceablePointer(); } - case Instruction::Call: + case Instruction::Call: { + if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) { + switch (II->getIntrinsicID()) { + case Intrinsic::bswap: + case Intrinsic::ctlz: + case Intrinsic::ctpop: + case Intrinsic::cttz: + case Intrinsic::objectsize: + case Intrinsic::sadd_with_overflow: + case Intrinsic::smul_with_overflow: + case Intrinsic::ssub_with_overflow: + case Intrinsic::uadd_with_overflow: + case Intrinsic::umul_with_overflow: + case Intrinsic::usub_with_overflow: + return true; + // TODO: some fp intrinsics are marked as having the same error handling + // as libm. They're safe to speculate when they won't error. + // TODO: are convert_{from,to}_fp16 safe? + // TODO: can we list target-specific intrinsics here? + default: break; + } + } return false; // The called function could have undefined behavior or - // side-effects. - // FIXME: We should special-case some intrinsics (bswap, - // overflow-checking arithmetic, etc.) + // side-effects, even if marked readnone nounwind. + } case Instruction::VAArg: case Instruction::Alloca: case Instruction::Invoke: |