diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/CloneFunction.cpp | 23 | ||||
| -rw-r--r-- | llvm/test/Transforms/Inline/infinite-loop-two-predecessors.ll | 32 |
2 files changed, 48 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp index 80736034005..9ae60962a63 100644 --- a/llvm/lib/Transforms/Utils/CloneFunction.cpp +++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp @@ -636,6 +636,22 @@ void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, Function::iterator Begin = cast<BasicBlock>(VMap[StartingBB])->getIterator(); Function::iterator I = Begin; while (I != NewFunc->end()) { + // We need to simplify conditional branches and switches with a constant + // operand. We try to prune these out when cloning, but if the + // simplification required looking through PHI nodes, those are only + // available after forming the full basic block. That may leave some here, + // and we still want to prune the dead code as early as possible. + // + // Do the folding before we check if the block is dead since we want code + // like + // bb: + // br i1 undef, label %bb, label %bb + // to be simplified to + // bb: + // br label %bb + // before we call I->getSinglePredecessor(). + ConstantFoldTerminator(&*I); + // Check if this block has become dead during inlining or other // simplifications. Note that the first block will appear dead, as it has // not yet been wired up properly. @@ -646,13 +662,6 @@ void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc, continue; } - // We need to simplify conditional branches and switches with a constant - // operand. We try to prune these out when cloning, but if the - // simplification required looking through PHI nodes, those are only - // available after forming the full basic block. That may leave some here, - // and we still want to prune the dead code as early as possible. - ConstantFoldTerminator(&*I); - BranchInst *BI = dyn_cast<BranchInst>(I->getTerminator()); if (!BI || BI->isConditional()) { ++I; continue; } diff --git a/llvm/test/Transforms/Inline/infinite-loop-two-predecessors.ll b/llvm/test/Transforms/Inline/infinite-loop-two-predecessors.ll new file mode 100644 index 00000000000..aa07315eb08 --- /dev/null +++ b/llvm/test/Transforms/Inline/infinite-loop-two-predecessors.ll @@ -0,0 +1,32 @@ +; RUN: opt -S -o - %s -inline | FileCheck %s + +define void @f1() { +bb.0: + br i1 false, label %bb.2, label %bb.1 + +bb.1: ; preds = %bb.0 + br label %bb.2 + +bb.2: ; preds = %bb.0, %bb.1 + %tmp0 = phi i1 [ true, %bb.1 ], [ false, %bb.0 ] + br i1 %tmp0, label %bb.4, label %bb.3 + +bb.3: ; preds = %bb.3, %bb.3 + br i1 undef, label %bb.3, label %bb.3 + +bb.4: ; preds = %bb.2 + ret void +} + +define void @f2() { +bb.0: + call void @f1() + ret void +} + +; f1 should be inlined into f2 and simplified/collapsed to nothing. + +; CHECK-LABEL: define void @f2() { +; CHECK-NEXT: bb.0: +; CHECK-NEXT: ret void +; CHECK-NEXT: } |