[mssa] Fix case when there is no definition in a block prior to an inserted use.
Summary:
Check that the first access before one being tested is valid.
Before this patch, if there was no definition prior to the Use being tested,
the first time Iter was deferenced, it hit the sentinel.
Reviewers: dberlin, gbiv
Subscribers: sanjoy, Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D33950
llvm-svn: 304926
diff --git a/llvm/unittests/Analysis/MemorySSA.cpp b/llvm/unittests/Analysis/MemorySSA.cpp
index 7295591..affa0e7 100644
--- a/llvm/unittests/Analysis/MemorySSA.cpp
+++ b/llvm/unittests/Analysis/MemorySSA.cpp
@@ -244,6 +244,52 @@
MSSA.verifyMemorySSA();
}
+TEST_F(MemorySSATest, SinkLoad) {
+ F = Function::Create(
+ FunctionType::get(B.getVoidTy(), {B.getInt8PtrTy()}, false),
+ GlobalValue::ExternalLinkage, "F", &M);
+ BasicBlock *Entry(BasicBlock::Create(C, "", F));
+ BasicBlock *Left(BasicBlock::Create(C, "", F));
+ BasicBlock *Right(BasicBlock::Create(C, "", F));
+ BasicBlock *Merge(BasicBlock::Create(C, "", F));
+ B.SetInsertPoint(Entry);
+ B.CreateCondBr(B.getTrue(), Left, Right);
+ B.SetInsertPoint(Left, Left->begin());
+ Argument *PointerArg = &*F->arg_begin();
+ B.SetInsertPoint(Left);
+ B.CreateBr(Merge);
+ B.SetInsertPoint(Right);
+ B.CreateBr(Merge);
+
+ // Load in left block
+ B.SetInsertPoint(Left, Left->begin());
+ LoadInst *LoadInst1 = B.CreateLoad(PointerArg);
+ // Store in merge block
+ B.SetInsertPoint(Merge, Merge->begin());
+ B.CreateStore(B.getInt8(16), PointerArg);
+
+ setupAnalyses();
+ MemorySSA &MSSA = *Analyses->MSSA;
+ MemorySSAUpdater Updater(&MSSA);
+
+ // Mimic sinking of a load:
+ // - clone load
+ // - insert in "exit" block
+ // - insert in mssa
+ // - remove from original block
+
+ LoadInst *LoadInstClone = cast<LoadInst>(LoadInst1->clone());
+ Merge->getInstList().insert(Merge->begin(), LoadInstClone);
+ MemoryAccess * NewLoadAccess =
+ Updater.createMemoryAccessInBB(LoadInstClone, nullptr,
+ LoadInstClone->getParent(),
+ MemorySSA::Beginning);
+ Updater.insertUse(cast<MemoryUse>(NewLoadAccess));
+ MSSA.verifyMemorySSA();
+ Updater.removeMemoryAccess(MSSA.getMemoryAccess(LoadInst1));
+ MSSA.verifyMemorySSA();
+}
+
TEST_F(MemorySSATest, MoveAStore) {
// We create a diamond where there is a in the entry, a store on one side, and
// a load at the end. After building MemorySSA, we test updating by moving