[Verifier] Fix performance regression for LTO builds
Summary:
Fix a significant performance regression by introducing GlobalValueVisited field and reusing the map.
This is a follow up to r257823 that slowed down linking Chrome with LTO by 2.5x.
If you revert this commit, please, also revert r257823.
BUG=https://llvm.org/bugs/show_bug.cgi?id=26214
Reviewers: pcc, loladiro, joker.eph
Subscribers: krasin1, joker.eph, loladiro, pcc
Differential Revision: http://reviews.llvm.org/D16338
llvm-svn: 258297
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 8db7fec..4018460 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -217,6 +217,12 @@
/// Cache of constants visited in search of ConstantExprs.
SmallPtrSet<const Constant *, 32> ConstantExprVisited;
+ // Verify that this GlobalValue is only used in this module.
+ // This map is used to avoid visiting uses twice. We can arrive at a user
+ // twice, if they have multiple operands. In particular for very large
+ // constant expressions, we can arrive at a particular user many times.
+ SmallPtrSet<const Value *, 32> GlobalValueVisited;
+
void checkAtomicMemAccessSize(const Module *M, Type *Ty,
const Instruction *I);
public:
@@ -494,12 +500,7 @@
if (GV.isDeclarationForLinker())
Assert(!GV.hasComdat(), "Declaration may not be in a Comdat!", &GV);
- // Verify that this GlobalValue is only used in this module.
- // This map is used to avoid visiting uses twice. We can arrive at a user
- // twice, if they have multiple operands. In particular for very large
- // constant expressions, we can arrive at a particular user many times.
- SmallPtrSet<const Value *, 32> Visited;
- forEachUser(&GV, Visited, [&](const Value *V) -> bool {
+ forEachUser(&GV, GlobalValueVisited, [&](const Value *V) -> bool {
if (const Instruction *I = dyn_cast<Instruction>(V)) {
if (!I->getParent() || !I->getParent()->getParent())
CheckFailed("Global is referenced by parentless instruction!", &GV,