| ; edgefailure - This function illustrates how SCCP is not doing it's job. This |
| ; function should be optimized almost completely away: the loop should be |
| ; analyzed to detect that the body executes exactly once, and thus the branch |
| ; can be eliminated and code becomes trivially dead. This is distilled from a |
| ; real benchmark (mst from Olden benchmark, MakeGraph function). When SCCP is |
| ; fixed, this should be eliminated by a single SCCP application. |
| ; |
| ; RUN: opt < %s -sccp -S | not grep loop |
| |
| define i32* @test() { |
| bb1: |
| %A = malloc i32 ; <i32*> [#uses=2] |
| br label %bb2 |
| bb2: ; preds = %bb2, %bb1 |
| ;; Always 0 |
| %i = phi i32 [ %i2, %bb2 ], [ 0, %bb1 ] ; <i32> [#uses=2] |
| ;; Always 1 |
| %i2 = add i32 %i, 1 ; <i32> [#uses=2] |
| store i32 %i, i32* %A |
| ;; Always false |
| %loop = icmp sle i32 %i2, 0 ; <i1> [#uses=1] |
| br i1 %loop, label %bb2, label %bb3 |
| bb3: ; preds = %bb2 |
| ret i32* %A |
| } |
| |
