| Philip Reames | 44456b8 | 2016-02-02 03:15:40 +0000 | [diff] [blame] | 1 | ; RUN: opt -S -jump-threading < %s | FileCheck %s |
| 2 | |
| 3 | define i8 @test(i32 %a, i32 %length) { |
| 4 | ; CHECK-LABEL: @test |
| 5 | entry: |
| 6 | ; CHECK: br label %backedge |
| 7 | br label %loop |
| 8 | |
| 9 | loop: |
| 10 | ; CHECK-LABEL: backedge: |
| 11 | ; CHECK: phi i32 |
| 12 | ; CHECK: br i1 %cont, label %backedge, label %exit |
| 13 | %iv = phi i32 [0, %entry], [%iv.next, %backedge] |
| 14 | ;; We can use an inductive argument to prove %iv is always positive |
| 15 | %cnd = icmp sge i32 %iv, 0 |
| 16 | br i1 %cnd, label %backedge, label %exit |
| 17 | |
| 18 | backedge: |
| 19 | %iv.next = add nsw i32 %iv, 1 |
| 20 | %cont = icmp slt i32 %iv.next, 400 |
| 21 | br i1 %cont, label %loop, label %exit |
| 22 | exit: |
| 23 | ret i8 0 |
| 24 | } |
| 25 | |