diff options
| author | Dan Gohman <sunfish@mozilla.com> | 2014-03-15 15:20:54 -0700 |
|---|---|---|
| committer | Dan Gohman <sunfish@mozilla.com> | 2014-03-15 16:28:55 -0700 |
| commit | 8bcbabf86eb3d09086221aca4286a65c09f597bd (patch) | |
| tree | 9e99e441674e5363dd7d5370e35530de2f43975d /test | |
| parent | 4966d3e8f33d27b41df3ab7802005afdfbeac3ef (diff) | |
Handle conflicting lifetime markers conservatively.
Avoid infinite looping in AllocaManager::computeInterBlockLiveness,
without using new temporary variables. This also makes it clear that
the algorithm is conservative in the face of conflicting liveness
intrinsics.
Diffstat (limited to 'test')
| -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 |