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Diffstat (limited to 'test/CodeGen/JS/alloca-contradiction.ll')
| -rw-r--r-- | test/CodeGen/JS/alloca-contradiction.ll | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/test/CodeGen/JS/alloca-contradiction.ll b/test/CodeGen/JS/alloca-contradiction.ll new file mode 100644 index 0000000000..82b1bf87c9 --- /dev/null +++ b/test/CodeGen/JS/alloca-contradiction.ll @@ -0,0 +1,35 @@ +; RUN: llc < %s + +; In theory, the @llvm.lifetime intrinsics shouldn't contradict each other, but +; in practice they apparently do sometimes. When they do, we should probably be +; conservative. + +target datalayout = "e-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-p:32:32:32-v128:32:128-n32-S128" +target triple = "asmjs-unknown-emscripten" + +; Don't merge these two allocas, even though lifetime markers may initially +; appear to indicate that it's safe, because they also indicate that it's +; unsafe. + +; CHECK: foo +; CHECK: HEAP8[$p] = 0; +; CHECK: HEAP8[$q] = 1; +define void @foo() nounwind { +entry: + %p = alloca i8 + %q = alloca i8 + br label %loop + +loop: + call void @llvm.lifetime.end(i64 1, i8* %q) + store volatile i8 0, i8* %p + store volatile i8 1, i8* %q + call void @llvm.lifetime.start(i64 1, i8* %p) + br i1 undef, label %loop, label %end + +end: ; preds = %red + ret void +} + +declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind +declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind |