| ; Checks whether dead loops with multiple exits can be eliminated. |
| ; Note that we loop simplify and LCSSA over the test cases to make sure the |
| ; critical components remain after those passes and are visible to the loop |
| ; deletion pass. |
| ; |
| ; RUN: opt < %s -passes=loop-simplify,lcssa -S | FileCheck %s --check-prefixes=CHECK,BEFORE |
| ; RUN: opt < %s -passes=no-op-loop -S | FileCheck %s --check-prefixes=CHECK,BEFORE |
| ; RUN: opt < %s -passes=loop-deletion -S | FileCheck %s --check-prefixes=CHECK,AFTER |
| |
| |
| define void @foo(i64 %n, i64 %m) nounwind { |
| ; CHECK-LABEL: @foo( |
| |
| entry: |
| br label %bb |
| ; CHECK: entry: |
| ; BEFORE-NEXT: br label %bb |
| ; AFTER-NEXT: br label %return |
| |
| bb: |
| %x.0 = phi i64 [ 0, %entry ], [ %t0, %bb2 ] |
| %t0 = add i64 %x.0, 1 |
| %t1 = icmp slt i64 %x.0, %n |
| br i1 %t1, label %bb2, label %return |
| ; BEFORE: bb: |
| ; BEFORE: br i1 {{.*}}, label %bb2, label %return |
| ; AFTER-NOT: bb: |
| ; AFTER-NOT: br |
| |
| bb2: |
| %t2 = icmp slt i64 %x.0, %m |
| br i1 %t1, label %bb, label %return |
| ; BEFORE: bb2: |
| ; BEFORE: br i1 {{.*}}, label %bb, label %return |
| ; AFTER-NOT: bb2: |
| ; AFTER-NOT: br |
| |
| return: |
| ret void |
| ; CHECK: return: |
| ; CHECK-NEXT: ret void |
| } |
| |
| define i64 @bar(i64 %n, i64 %m, i64 %maybe_zero) nounwind { |
| ; CHECK-LABEL: @bar( |
| |
| entry: |
| br label %bb |
| ; CHECK: entry: |
| ; BEFORE-NEXT: br label %bb |
| ; AFTER-NEXT: br label %return |
| |
| bb: |
| %x.0 = phi i64 [ 0, %entry ], [ %t0, %bb3 ] |
| %t0 = add i64 %x.0, 1 |
| %t1 = icmp slt i64 %x.0, %n |
| br i1 %t1, label %bb2, label %return |
| ; BEFORE: bb: |
| ; BEFORE: br i1 {{.*}}, label %bb2, label %return |
| ; AFTER-NOT: bb: |
| ; AFTER-NOT: br |
| |
| bb2: |
| %t2 = icmp slt i64 %x.0, %m |
| ; This unused division prevents unifying this loop exit path with others |
| ; because it can be deleted but cannot be hoisted. |
| %unused1 = udiv i64 42, %maybe_zero |
| br i1 %t2, label %bb3, label %return |
| ; BEFORE: bb2: |
| ; BEFORE: br i1 {{.*}}, label %bb3, label %return |
| ; AFTER-NOT: bb2: |
| ; AFTER-NOT: br |
| |
| bb3: |
| %t3 = icmp slt i64 %x.0, %m |
| ; This unused division prevents unifying this loop exit path with others |
| ; because it can be deleted but cannot be hoisted. |
| %unused2 = sdiv i64 42, %maybe_zero |
| br i1 %t3, label %bb, label %return |
| ; BEFORE: bb3: |
| ; BEFORE: br i1 {{.*}}, label %bb, label %return |
| ; AFTER-NOT: bb3: |
| ; AFTER-NOT: br |
| |
| return: |
| %x.lcssa = phi i64 [ 10, %bb ], [ 10, %bb2 ], [ 10, %bb3 ] |
| ret i64 %x.lcssa |
| ; CHECK: return: |
| ; BEFORE-NEXT: %[[X:.*]] = phi i64 [ 10, %bb ], [ 10, %bb2 ], [ 10, %bb3 ] |
| ; AFTER-NEXT: %[[X:.*]] = phi i64 [ 10, %entry ] |
| ; CHECK-NEXT: ret i64 %[[X]] |
| } |
| |
| ; This function has a loop which looks like @bar's but that cannot be deleted |
| ; because which path we exit through determines which value is selected. |
| define i64 @baz(i64 %n, i64 %m, i64 %maybe_zero) nounwind { |
| ; CHECK-LABEL: @baz( |
| |
| entry: |
| br label %bb |
| ; CHECK: entry: |
| ; CHECK-NEXT: br label %bb |
| |
| bb: |
| %x.0 = phi i64 [ 0, %entry ], [ %t0, %bb3 ] |
| %t0 = add i64 %x.0, 1 |
| %t1 = icmp slt i64 %x.0, %n |
| br i1 %t1, label %bb2, label %return |
| ; CHECK: bb: |
| ; CHECK: br i1 {{.*}}, label %bb2, label %return |
| |
| bb2: |
| %t2 = icmp slt i64 %x.0, %m |
| ; This unused division prevents unifying this loop exit path with others |
| ; because it can be deleted but cannot be hoisted. |
| %unused1 = udiv i64 42, %maybe_zero |
| br i1 %t2, label %bb3, label %return |
| ; CHECK: bb2: |
| ; CHECK: br i1 {{.*}}, label %bb3, label %return |
| |
| bb3: |
| %t3 = icmp slt i64 %x.0, %m |
| ; This unused division prevents unifying this loop exit path with others |
| ; because it can be deleted but cannot be hoisted. |
| %unused2 = sdiv i64 42, %maybe_zero |
| br i1 %t3, label %bb, label %return |
| ; CHECK: bb3: |
| ; CHECK: br i1 {{.*}}, label %bb, label %return |
| |
| return: |
| %x.lcssa = phi i64 [ 12, %bb ], [ 10, %bb2 ], [ 10, %bb3 ] |
| ret i64 %x.lcssa |
| ; CHECK: return: |
| ; CHECK-NEXT: %[[X:.*]] = phi i64 [ 12, %bb ], [ 10, %bb2 ], [ 10, %bb3 ] |
| ; CHECK-NEXT: ret i64 %[[X]] |
| } |