| ; RUN: opt %s -lowerswitch -S | FileCheck %s |
| |
| define void @foo(i32 %x, i32* %p) { |
| ; Cases 2 and 4 are removed and become the new default case. |
| ; It is now enough to use two icmps to lower the switch. |
| ; |
| ; CHECK-LABEL: @foo |
| ; CHECK: icmp slt i32 %x, 5 |
| ; CHECK: icmp eq i32 %x, 1 |
| ; CHECK-NOT: icmp |
| ; |
| entry: |
| switch i32 %x, label %default [ |
| i32 1, label %bb0 |
| i32 2, label %popular |
| i32 4, label %popular |
| i32 5, label %bb1 |
| ] |
| bb0: |
| store i32 0, i32* %p |
| br label %exit |
| bb1: |
| store i32 1, i32* %p |
| br label %exit |
| popular: |
| store i32 2, i32* %p |
| br label %exit |
| exit: |
| ret void |
| default: |
| unreachable |
| } |
| |
| define void @unreachable_gap(i64 %x, i32* %p) { |
| ; Cases 6 and INT64_MAX become the new default, but we still exploit the fact |
| ; that 3-4 is unreachable, so four icmps is enough. |
| |
| ; CHECK-LABEL: @unreachable_gap |
| ; CHECK: icmp slt i64 %x, 2 |
| ; CHECK: icmp slt i64 %x, 5 |
| ; CHECK: icmp eq i64 %x, 5 |
| ; CHECK: icmp slt i64 %x, 1 |
| ; CHECK-NOT: icmp |
| |
| entry: |
| switch i64 %x, label %default [ |
| i64 -9223372036854775808, label %bb0 |
| i64 1, label %bb1 |
| i64 2, label %bb2 |
| i64 5, label %bb3 |
| i64 6, label %bb4 |
| i64 9223372036854775807, label %bb4 |
| ] |
| bb0: |
| store i32 0, i32* %p |
| br label %exit |
| bb1: |
| store i32 1, i32* %p |
| br label %exit |
| bb2: |
| store i32 2, i32* %p |
| br label %exit |
| bb3: |
| store i32 3, i32* %p |
| br label %exit |
| bb4: |
| store i32 4, i32* %p |
| br label %exit |
| exit: |
| ret void |
| default: |
| unreachable |
| } |
| |
| |
| |
| define void @nocases(i32 %x, i32* %p) { |
| ; Don't fall over when there are no cases. |
| ; |
| ; CHECK-LABEL: @nocases |
| ; CHECK-LABEL: entry |
| ; CHECK-NEXT: br label %default |
| ; |
| entry: |
| switch i32 %x, label %default [ |
| ] |
| default: |
| unreachable |
| } |
| |
| define void @nocasesleft(i32 %x, i32* %p) { |
| ; Cases 2 and 4 are removed and we are left with no cases. |
| ; |
| ; CHECK-LABEL: @nocasesleft |
| ; CHECK-LABEL: entry |
| ; CHECK-NEXT: br label %popular |
| ; |
| entry: |
| switch i32 %x, label %default [ |
| i32 2, label %popular |
| i32 4, label %popular |
| ] |
| popular: |
| store i32 2, i32* %p |
| br label %exit |
| exit: |
| ret void |
| default: |
| unreachable |
| } |