diff options
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 20 | ||||
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/attr-convergent.ll | 28 |
2 files changed, 34 insertions, 14 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index f88334a05ea..3c8317252ee 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1690,19 +1690,6 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB, return true; } -/// \returns True if this block contains a CallInst with the NoDuplicate -/// attribute. -static bool HasNoDuplicateCall(const BasicBlock *BB) { - for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E; ++I) { - const CallInst *CI = dyn_cast<CallInst>(I); - if (!CI) - continue; - if (CI->cannotDuplicate()) - return true; - } - return false; -} - /// Return true if we can thread a branch across this block. static bool BlockIsSimpleEnoughToThreadThrough(BasicBlock *BB) { BranchInst *BI = cast<BranchInst>(BB->getTerminator()); @@ -1747,7 +1734,12 @@ static bool FoldCondBranchOnPHI(BranchInst *BI, const DataLayout &DL) { // Now we know that this block has multiple preds and two succs. if (!BlockIsSimpleEnoughToThreadThrough(BB)) return false; - if (HasNoDuplicateCall(BB)) return false; + // Can't fold blocks that contain noduplicate or convergent calls. + if (llvm::any_of(*BB, [](const Instruction &I) { + const CallInst *CI = dyn_cast<CallInst>(&I); + return CI && (CI->cannotDuplicate() || CI->isConvergent()); + })) + return false; // Okay, this is a simple enough basic block. See if any phi values are // constants. diff --git a/llvm/test/Transforms/SimplifyCFG/attr-convergent.ll b/llvm/test/Transforms/SimplifyCFG/attr-convergent.ll new file mode 100644 index 00000000000..a5f363d055a --- /dev/null +++ b/llvm/test/Transforms/SimplifyCFG/attr-convergent.ll @@ -0,0 +1,28 @@ +; RUN: opt < %s -simplifycfg -S | FileCheck %s + +; Checks that the SimplifyCFG pass won't duplicate a call to a function marked +; convergent. +; +; CHECK: call void @barrier +; CHECK-NOT: call void @barrier +define void @check(i1 %cond, i32* %out) { +entry: + br i1 %cond, label %if.then, label %if.end + +if.then: + store i32 5, i32* %out + br label %if.end + +if.end: + %x = phi i1 [ true, %entry ], [ false, %if.then ] + call void @barrier() + br i1 %x, label %cond.end, label %cond.false + +cond.false: + br label %cond.end + +cond.end: + ret void +} + +declare void @barrier() convergent |
