forked from OSchip/llvm-project
180 lines
4.1 KiB
LLVM
180 lines
4.1 KiB
LLVM
; RUN: opt %s -S -simplifycfg | FileCheck %s
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declare void @foo(i32)
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define void @test(i1 %a) {
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; CHECK-LABEL: @test
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; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false
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switch i1 %a, label %default [i1 1, label %true
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i1 0, label %false]
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true:
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call void @foo(i32 1)
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ret void
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false:
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call void @foo(i32 3)
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ret void
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default:
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call void @foo(i32 2)
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ret void
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}
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define void @test2(i2 %a) {
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; CHECK-LABEL: @test2
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switch i2 %a, label %default [i2 0, label %case0
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i2 1, label %case1
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i2 2, label %case2
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i2 3, label %case3]
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case0:
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call void @foo(i32 0)
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ret void
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case1:
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call void @foo(i32 1)
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ret void
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case2:
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call void @foo(i32 2)
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ret void
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case3:
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call void @foo(i32 3)
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ret void
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default:
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; CHECK-LABEL: default1:
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; CHECK-NEXT: unreachable
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call void @foo(i32 4)
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ret void
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}
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; This one is a negative test - we know the value of the default,
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; but that's about it
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define void @test3(i2 %a) {
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; CHECK-LABEL: @test3
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switch i2 %a, label %default [i2 0, label %case0
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i2 1, label %case1
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i2 2, label %case2]
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case0:
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call void @foo(i32 0)
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ret void
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case1:
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call void @foo(i32 1)
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ret void
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case2:
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call void @foo(i32 2)
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ret void
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default:
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; CHECK-LABEL: default:
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; CHECK-NEXT: call void @foo
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call void @foo(i32 0)
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ret void
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}
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; Negative test - check for possible overflow when computing
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; number of possible cases.
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define void @test4(i128 %a) {
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; CHECK-LABEL: @test4
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switch i128 %a, label %default [i128 0, label %case0
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i128 1, label %case1]
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case0:
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call void @foo(i32 0)
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ret void
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case1:
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call void @foo(i32 1)
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ret void
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default:
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; CHECK-LABEL: default:
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; CHECK-NEXT: call void @foo
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call void @foo(i32 0)
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ret void
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}
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; All but one bit known zero
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define void @test5(i8 %a) {
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; CHECK-LABEL: @test5
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; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false
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%cmp = icmp ult i8 %a, 2
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call void @llvm.assume(i1 %cmp)
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switch i8 %a, label %default [i8 1, label %true
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i8 0, label %false]
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true:
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call void @foo(i32 1)
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ret void
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false:
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call void @foo(i32 3)
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ret void
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default:
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call void @foo(i32 2)
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ret void
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}
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;; All but one bit known one
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define void @test6(i8 %a) {
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; CHECK-LABEL: @test6
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; CHECK: @llvm.assume
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; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false
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%and = and i8 %a, 254
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%cmp = icmp eq i8 %and, 254
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call void @llvm.assume(i1 %cmp)
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switch i8 %a, label %default [i8 255, label %true
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i8 254, label %false]
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true:
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call void @foo(i32 1)
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ret void
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false:
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call void @foo(i32 3)
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ret void
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default:
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call void @foo(i32 2)
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ret void
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}
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; Check that we can eliminate both dead cases and dead defaults
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; within a single run of simplify-cfg
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define void @test7(i8 %a) {
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; CHECK-LABEL: @test7
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; CHECK: @llvm.assume
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; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false
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%and = and i8 %a, 254
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%cmp = icmp eq i8 %and, 254
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call void @llvm.assume(i1 %cmp)
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switch i8 %a, label %default [i8 255, label %true
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i8 254, label %false
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i8 0, label %also_dead]
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true:
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call void @foo(i32 1)
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ret void
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false:
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call void @foo(i32 3)
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ret void
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also_dead:
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call void @foo(i32 5)
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ret void
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default:
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call void @foo(i32 2)
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ret void
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}
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;; All but one bit known undef
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;; Note: This is currently testing an optimization which doesn't trigger. The
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;; case this is protecting against is that a bit could be assumed both zero
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;; *or* one given we know it's undef. ValueTracking doesn't do this today,
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;; but it doesn't hurt to confirm.
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define void @test8(i8 %a) {
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; CHECK-LABEL: @test8(
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; CHECK: switch i8
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%and = and i8 %a, 254
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%cmp = icmp eq i8 %and, undef
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call void @llvm.assume(i1 %cmp)
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switch i8 %a, label %default [i8 255, label %true
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i8 254, label %false]
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true:
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call void @foo(i32 1)
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ret void
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false:
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call void @foo(i32 3)
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ret void
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default:
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call void @foo(i32 2)
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ret void
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}
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declare void @llvm.assume(i1)
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