diff options
| author | Dimitry Andric <dim@FreeBSD.org> | 2021-06-18 19:08:25 +0000 |
|---|---|---|
| committer | Dimitry Andric <dim@FreeBSD.org> | 2021-06-18 19:08:25 +0000 |
| commit | e4bbddaec8689e1b24f25e88958bea700e989542 (patch) | |
| tree | 054adb83b829924d4a01d719429d91d42d885e77 /llvm/lib/Analysis/ValueTracking.cpp | |
| parent | b4125f7d51da2bb55d3b850dba9a69c201c3422c (diff) | |
Vendor import of llvm-project branch release/12.x llvmorg-12.0.1-rc2-0-ge7dac564cd0e, a.k.a. 12.0.1 rc2.llvmorg-12.0.1-rc2-0-ge7dac564cd0e
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index e174c5efe424..75486d3c80e7 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -5150,6 +5150,9 @@ static bool programUndefinedIfUndefOrPoison(const Value *V, return false; } + // Limit number of instructions we look at, to avoid scanning through large + // blocks. The current limit is chosen arbitrarily. + unsigned ScanLimit = 32; BasicBlock::const_iterator End = BB->end(); if (!PoisonOnly) { @@ -5160,6 +5163,11 @@ static bool programUndefinedIfUndefOrPoison(const Value *V, // For example, 'udiv x, (undef | 1)' isn't UB. for (auto &I : make_range(Begin, End)) { + if (isa<DbgInfoIntrinsic>(I)) + continue; + if (--ScanLimit == 0) + break; + if (const auto *CB = dyn_cast<CallBase>(&I)) { for (unsigned i = 0; i < CB->arg_size(); ++i) { if (CB->paramHasAttr(i, Attribute::NoUndef) && @@ -5186,9 +5194,12 @@ static bool programUndefinedIfUndefOrPoison(const Value *V, for_each(V->users(), Propagate); Visited.insert(BB); - unsigned Iter = 0; - while (Iter++ < MaxAnalysisRecursionDepth) { + while (true) { for (auto &I : make_range(Begin, End)) { + if (isa<DbgInfoIntrinsic>(I)) + continue; + if (--ScanLimit == 0) + return false; if (mustTriggerUB(&I, YieldsPoison)) return true; if (!isGuaranteedToTransferExecutionToSuccessor(&I)) |