diff options
| -rw-r--r-- | polly/lib/CodeGen/CodeGeneration.cpp | 34 | ||||
| -rw-r--r-- | polly/test/Isl/CodeGen/stack-overflow-in-load-hoisting.ll | 2 |
2 files changed, 29 insertions, 7 deletions
diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp index d66ff944fc7..ec10b3e6255 100644 --- a/polly/lib/CodeGen/CodeGeneration.cpp +++ b/polly/lib/CodeGen/CodeGeneration.cpp @@ -110,6 +110,17 @@ public: } } + /// @brief Mark a basic block unreachable. + /// + /// Marks the basic block @p Block unreachable by equipping it with an + /// UnreachableInst. + void markBlockUnreachable(BasicBlock &Block, PollyIRBuilder &Builder) { + auto *OrigTerminator = Block.getTerminator(); + Builder.SetInsertPoint(OrigTerminator); + Builder.CreateUnreachable(); + OrigTerminator->eraseFromParent(); + } + /// @brief Generate LLVM-IR for the SCoP @p S. bool runOnScop(Scop &S) override { AI = &getAnalysis<IslAstInfo>(); @@ -146,7 +157,7 @@ public: // code generating this scop. BasicBlock *StartBlock = executeScopConditionally(S, this, Builder.getTrue()); - auto SplitBlock = StartBlock->getSinglePredecessor(); + auto *SplitBlock = StartBlock->getSinglePredecessor(); // First generate code for the hoisted invariant loads and transitively the // parameters they reference. Afterwards, for the remaining parameters that @@ -156,15 +167,26 @@ public: Builder.SetInsertPoint(SplitBlock->getTerminator()); if (!NodeBuilder.preloadInvariantLoads()) { + // Patch the introduced branch condition to ensure that we always execute + // the original SCoP. auto *FalseI1 = Builder.getFalse(); auto *SplitBBTerm = Builder.GetInsertBlock()->getTerminator(); SplitBBTerm->setOperand(0, FalseI1); - auto *StartBBTerm = StartBlock->getTerminator(); - Builder.SetInsertPoint(StartBBTerm); - Builder.CreateUnreachable(); - StartBBTerm->eraseFromParent(); - isl_ast_node_free(AstRoot); + // Since the other branch is hence ignored we mark it as unreachable and + // adjust the dominator tree accordingly. + auto *ExitingBlock = StartBlock->getUniqueSuccessor(); + assert(ExitingBlock); + auto *MergeBlock = ExitingBlock->getUniqueSuccessor(); + assert(MergeBlock); + markBlockUnreachable(*StartBlock, Builder); + markBlockUnreachable(*ExitingBlock, Builder); + auto *ExitingBB = R->getExitingBlock(); + assert(ExitingBB); + DT->changeImmediateDominator(MergeBlock, ExitingBB); + DT->eraseNode(ExitingBlock); + + isl_ast_node_free(AstRoot); } else { NodeBuilder.addParameters(S.getContext()); diff --git a/polly/test/Isl/CodeGen/stack-overflow-in-load-hoisting.ll b/polly/test/Isl/CodeGen/stack-overflow-in-load-hoisting.ll index 9534b7270ea..e43baca5462 100644 --- a/polly/test/Isl/CodeGen/stack-overflow-in-load-hoisting.ll +++ b/polly/test/Isl/CodeGen/stack-overflow-in-load-hoisting.ll @@ -1,4 +1,4 @@ -; RUN: opt %loadPolly -polly-codegen -S < %s | FileCheck %s +; RUN: opt %loadPolly -verify-dom-info -polly-codegen -S < %s | FileCheck %s ; ; This caused an infinite recursion during invariant load hoisting at some ; point. Check it does not and we add a "false" runtime check. |
