1 ; RUN: opt %s -S -simplifycfg | FileCheck %s 2 declare void @foo(i32) 3 4 define void @test(i1 %a) { 5 ; CHECK-LABEL: @test 6 ; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false 7 switch i1 %a, label %default [i1 1, label %true 8 i1 0, label %false] 9 true: 10 call void @foo(i32 1) 11 ret void 12 false: 13 call void @foo(i32 3) 14 ret void 15 default: 16 call void @foo(i32 2) 17 ret void 18 } 19 20 define void @test2(i2 %a) { 21 ; CHECK-LABEL: @test2 22 switch i2 %a, label %default [i2 0, label %case0 23 i2 1, label %case1 24 i2 2, label %case2 25 i2 3, label %case3] 26 case0: 27 call void @foo(i32 0) 28 ret void 29 case1: 30 call void @foo(i32 1) 31 ret void 32 case2: 33 call void @foo(i32 2) 34 ret void 35 case3: 36 call void @foo(i32 3) 37 ret void 38 default: 39 ; CHECK-LABEL: default1: 40 ; CHECK-NEXT: unreachable 41 call void @foo(i32 4) 42 ret void 43 } 44 45 ; This one is a negative test - we know the value of the default, 46 ; but that's about it 47 define void @test3(i2 %a) { 48 ; CHECK-LABEL: @test3 49 switch i2 %a, label %default [i2 0, label %case0 50 i2 1, label %case1 51 i2 2, label %case2] 52 53 case0: 54 call void @foo(i32 0) 55 ret void 56 case1: 57 call void @foo(i32 1) 58 ret void 59 case2: 60 call void @foo(i32 2) 61 ret void 62 default: 63 ; CHECK-LABEL: default: 64 ; CHECK-NEXT: call void @foo 65 call void @foo(i32 0) 66 ret void 67 } 68 69 ; Negative test - check for possible overflow when computing 70 ; number of possible cases. 71 define void @test4(i128 %a) { 72 ; CHECK-LABEL: @test4 73 switch i128 %a, label %default [i128 0, label %case0 74 i128 1, label %case1] 75 76 case0: 77 call void @foo(i32 0) 78 ret void 79 case1: 80 call void @foo(i32 1) 81 ret void 82 default: 83 ; CHECK-LABEL: default: 84 ; CHECK-NEXT: call void @foo 85 call void @foo(i32 0) 86 ret void 87 } 88 89 ; All but one bit known zero 90 define void @test5(i8 %a) { 91 ; CHECK-LABEL: @test5 92 ; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false 93 %cmp = icmp ult i8 %a, 2 94 call void @llvm.assume(i1 %cmp) 95 switch i8 %a, label %default [i8 1, label %true 96 i8 0, label %false] 97 true: 98 call void @foo(i32 1) 99 ret void 100 false: 101 call void @foo(i32 3) 102 ret void 103 default: 104 call void @foo(i32 2) 105 ret void 106 } 107 108 ;; All but one bit known one 109 define void @test6(i8 %a) { 110 ; CHECK-LABEL: @test6 111 ; CHECK: @llvm.assume 112 ; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false 113 %and = and i8 %a, 254 114 %cmp = icmp eq i8 %and, 254 115 call void @llvm.assume(i1 %cmp) 116 switch i8 %a, label %default [i8 255, label %true 117 i8 254, label %false] 118 true: 119 call void @foo(i32 1) 120 ret void 121 false: 122 call void @foo(i32 3) 123 ret void 124 default: 125 call void @foo(i32 2) 126 ret void 127 } 128 129 ; Check that we can eliminate both dead cases and dead defaults 130 ; within a single run of simplify-cfg 131 define void @test7(i8 %a) { 132 ; CHECK-LABEL: @test7 133 ; CHECK: @llvm.assume 134 ; CHECK: br i1 [[IGNORE:%.*]], label %true, label %false 135 %and = and i8 %a, 254 136 %cmp = icmp eq i8 %and, 254 137 call void @llvm.assume(i1 %cmp) 138 switch i8 %a, label %default [i8 255, label %true 139 i8 254, label %false 140 i8 0, label %also_dead] 141 true: 142 call void @foo(i32 1) 143 ret void 144 false: 145 call void @foo(i32 3) 146 ret void 147 also_dead: 148 call void @foo(i32 5) 149 ret void 150 default: 151 call void @foo(i32 2) 152 ret void 153 } 154 155 ;; All but one bit known undef 156 ;; Note: This is currently testing an optimization which doesn't trigger. The 157 ;; case this is protecting against is that a bit could be assumed both zero 158 ;; *or* one given we know it's undef. ValueTracking doesn't do this today, 159 ;; but it doesn't hurt to confirm. 160 define void @test8(i8 %a) { 161 ; CHECK-LABEL: @test8( 162 ; CHECK: switch i8 163 %and = and i8 %a, 254 164 %cmp = icmp eq i8 %and, undef 165 call void @llvm.assume(i1 %cmp) 166 switch i8 %a, label %default [i8 255, label %true 167 i8 254, label %false] 168 true: 169 call void @foo(i32 1) 170 ret void 171 false: 172 call void @foo(i32 3) 173 ret void 174 default: 175 call void @foo(i32 2) 176 ret void 177 } 178 179 declare void @llvm.assume(i1) 180
