diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/EarlyCSE.cpp | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp index 04479b6e49a..da33c7aa836 100644 --- a/llvm/lib/Transforms/Scalar/EarlyCSE.cpp +++ b/llvm/lib/Transforms/Scalar/EarlyCSE.cpp @@ -658,10 +658,25 @@ bool EarlyCSE::processNode(DomTreeNode *Node) { if (match(Inst, m_Intrinsic<Intrinsic::experimental_guard>())) { if (auto *CondI = dyn_cast<Instruction>(cast<CallInst>(Inst)->getArgOperand(0))) { - // The condition we're on guarding here is true for all dominated - // locations. - if (SimpleValue::canHandle(CondI)) + if (SimpleValue::canHandle(CondI)) { + // Do we already know the actual value of this condition? + if (auto *KnownCond = AvailableValues.lookup(CondI)) { + // Is the condition known to be true? + if (isa<ConstantInt>(KnownCond) && + cast<ConstantInt>(KnownCond)->isOneValue()) { + DEBUG(dbgs() << "EarlyCSE removing guard: " << *Inst << '\n'); + removeMSSA(Inst); + Inst->eraseFromParent(); + Changed = true; + continue; + } else + // Use the known value if it wasn't true. + cast<CallInst>(Inst)->setArgOperand(0, KnownCond); + } + // The condition we're on guarding here is true for all dominated + // locations. AvailableValues.insert(CondI, ConstantInt::getTrue(BB->getContext())); + } } // Guard intrinsics read all memory, but don't write any memory. |
