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