diff --git a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp --- a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp +++ b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp @@ -285,6 +285,10 @@ else PI.runAfterPass(*Pass, *L, PassPA); + if (LAR.MSSA && !PassPA.getChecker().preserved()) + report_fatal_error("Loop pass manager using MemorySSA contains a pass " + "that does not preserve MemorySSA"); + #ifndef NDEBUG // LoopAnalysisResults should always be valid. // Note that we don't LAR.SE.verify() because that can change observed SE diff --git a/llvm/test/Other/loop-mssa-not-preserved.ll b/llvm/test/Other/loop-mssa-not-preserved.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Other/loop-mssa-not-preserved.ll @@ -0,0 +1,17 @@ +; RUN: not --crash opt -passes='loop-mssa(loop-unroll-full)' 2>&1 < %s | FileCheck %s + +; CHECK: LLVM ERROR: Loop pass manager using MemorySSA contains a pass that does not preserve MemorySSA + +define void @test() { +entry: + br label %loop + +loop: + %i = phi i32 [ 0, %entry ], [ %i.inc, %loop ] + %i.inc = add i32 %i, 1 + %c = icmp ult i32 %i, 8 + br i1 %c, label %loop, label %exit + +exit: + ret void +}