| ; RUN: opt -passes=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 |
| } |