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| ; 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
| }
|
|
