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Diffstat (limited to 'test/Transforms/JumpThreading/conservative-lvi.ll')
| -rw-r--r-- | test/Transforms/JumpThreading/conservative-lvi.ll | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/test/Transforms/JumpThreading/conservative-lvi.ll b/test/Transforms/JumpThreading/conservative-lvi.ll new file mode 100644 index 0000000..1ea8cdc --- /dev/null +++ b/test/Transforms/JumpThreading/conservative-lvi.ll @@ -0,0 +1,58 @@ +; RUN: opt -jump-threading -S %s | FileCheck %s + +; Check that we thread arg2neg -> checkpos -> end. +; +; LazyValueInfo would previously fail to analyze the value of %arg in arg2neg +; because its predecessing blocks (checkneg) hadn't been processed yet (PR21238) + +; CHECK-LABEL: @test_jump_threading +; CHECK: arg2neg: +; CHECK-NEXT: br i1 %arg1, label %end, label %checkpos.thread +; CHECK: checkpos.thread: +; CHECK-NEXT: br label %end + +define i32 @test_jump_threading(i1 %arg1, i32 %arg2) { +checkneg: + %cmp = icmp slt i32 %arg2, 0 + br i1 %cmp, label %arg2neg, label %checkpos + +arg2neg: + br i1 %arg1, label %end, label %checkpos + +checkpos: + %cmp2 = icmp sgt i32 %arg2, 0 + br i1 %cmp2, label %arg2pos, label %end + +arg2pos: + br label %end + +end: + %0 = phi i32 [ 1, %arg2neg ], [ 2, %checkpos ], [ 3, %arg2pos ] + ret i32 %0 +} + + +; arg2neg has an edge back to itself. If LazyValueInfo is not careful when +; visiting predecessors, it could get into an infinite loop. + +; CHECK-LABEL: test_infinite_loop + +define i32 @test_infinite_loop(i1 %arg1, i32 %arg2) { +checkneg: + %cmp = icmp slt i32 %arg2, 0 + br i1 %cmp, label %arg2neg, label %checkpos + +arg2neg: + br i1 %arg1, label %arg2neg, label %checkpos + +checkpos: + %cmp2 = icmp sgt i32 %arg2, 0 + br i1 %cmp2, label %arg2pos, label %end + +arg2pos: + br label %end + +end: + %0 = phi i32 [ 2, %checkpos ], [ 3, %arg2pos ] + ret i32 %0 +} |