1 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2 ; RUN: opt < %s -instsimplify -S | FileCheck %s 3 4 ; %r = shl nuw i8 C, %x 5 ; As per langref: If the nuw keyword is present, then the shift produces 6 ; a poison value if it shifts out any non-zero bits. 7 ; Thus, if the sign bit is set on C, then %x can only be 0, which means that 8 ; %r can only be C. 9 10 define i8 @shl_nuw (i8 %x) { 11 ; CHECK-LABEL: @shl_nuw( 12 ; CHECK-NEXT: ret i8 -1 13 ; 14 %ret = shl nuw i8 -1, %x 15 ; nuw here means that %x can only be 0 16 ret i8 %ret 17 } 18 19 define i8 @shl_nuw_nsw (i8 %x) { 20 ; CHECK-LABEL: @shl_nuw_nsw( 21 ; CHECK-NEXT: ret i8 -1 22 ; 23 %ret = shl nuw nsw i8 -1, %x 24 ; nuw here means that %x can only be 0 25 ret i8 %ret 26 } 27 28 define i8 @shl_128 (i8 %x) { 29 ; CHECK-LABEL: @shl_128( 30 ; CHECK-NEXT: ret i8 -128 31 ; 32 %ret = shl nuw i8 128, %x 33 ; 128 == 1<<7 == just the sign bit is set 34 ret i8 %ret 35 } 36 37 ; ============================================================================ ; 38 ; Positive tests with value range known 39 ; ============================================================================ ; 40 41 declare void @llvm.assume(i1 %cond); 42 43 define i8 @knownbits_negative(i8 %x, i8 %y) { 44 ; CHECK-LABEL: @knownbits_negative( 45 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 0 46 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 47 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 48 ; CHECK-NEXT: ret i8 [[RET]] 49 ; 50 %cmp = icmp slt i8 %x, 0 51 tail call void @llvm.assume(i1 %cmp) 52 %ret = shl nuw i8 %x, %y 53 ret i8 %ret 54 } 55 56 define i8 @knownbits_negativeorzero(i8 %x, i8 %y) { 57 ; CHECK-LABEL: @knownbits_negativeorzero( 58 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 1 59 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 60 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 61 ; CHECK-NEXT: ret i8 [[RET]] 62 ; 63 %cmp = icmp slt i8 %x, 1 64 tail call void @llvm.assume(i1 %cmp) 65 %ret = shl nuw i8 %x, %y 66 ret i8 %ret 67 } 68 69 ; ============================================================================ ; 70 ; Vectors 71 ; ============================================================================ ; 72 73 define <2 x i8> @shl_vec(<2 x i8> %x) { 74 ; CHECK-LABEL: @shl_vec( 75 ; CHECK-NEXT: ret <2 x i8> <i8 -1, i8 -1> 76 ; 77 %ret = shl nuw <2 x i8> <i8 -1, i8 -1>, %x 78 ret <2 x i8> %ret 79 } 80 81 define <3 x i8> @shl_vec_undef(<3 x i8> %x) { 82 ; CHECK-LABEL: @shl_vec_undef( 83 ; CHECK-NEXT: ret <3 x i8> <i8 -1, i8 undef, i8 -1> 84 ; 85 %ret = shl nuw <3 x i8> <i8 -1, i8 undef, i8 -1>, %x 86 ret <3 x i8> %ret 87 } 88 89 define <2 x i8> @shl_vec_nonsplat(<2 x i8> %x) { 90 ; CHECK-LABEL: @shl_vec_nonsplat( 91 ; CHECK-NEXT: ret <2 x i8> <i8 -1, i8 -2> 92 ; 93 %ret = shl nuw <2 x i8> <i8 -1, i8 -2>, %x 94 ret <2 x i8> %ret 95 } 96 97 ; ============================================================================ ; 98 ; Negative tests. Should not be folded. 99 ; ============================================================================ ; 100 101 define i8 @shl_127 (i8 %x) { 102 ; CHECK-LABEL: @shl_127( 103 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 127, [[X:%.*]] 104 ; CHECK-NEXT: ret i8 [[RET]] 105 ; 106 %ret = shl nuw i8 127, %x 107 ; 127 == (1<<7)-1 == all bits except the sign bit are set. 108 ret i8 %ret 109 } 110 111 define i8 @bad_shl (i8 %x) { 112 ; CHECK-LABEL: @bad_shl( 113 ; CHECK-NEXT: [[RET:%.*]] = shl i8 -1, [[X:%.*]] 114 ; CHECK-NEXT: ret i8 [[RET]] 115 ; 116 %ret = shl i8 -1, %x ; need nuw 117 ret i8 %ret 118 } 119 120 define i8 @bad_nsw (i8 %x) { 121 ; CHECK-LABEL: @bad_nsw( 122 ; CHECK-NEXT: [[RET:%.*]] = shl nsw i8 -1, [[X:%.*]] 123 ; CHECK-NEXT: ret i8 [[RET]] 124 ; 125 %ret = shl nsw i8 -1, %x ; need nuw 126 ret i8 %ret 127 } 128 129 ; First `shl` operand is not `-1` constant 130 131 define i8 @bad_shl0(i8 %shlop1, i8 %x) { 132 ; CHECK-LABEL: @bad_shl0( 133 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[SHLOP1:%.*]], [[X:%.*]] 134 ; CHECK-NEXT: ret i8 [[RET]] 135 ; 136 %ret = shl nuw i8 %shlop1, %x 137 ret i8 %ret 138 } 139 140 ; Bad shl nuw constant 141 142 define i8 @bad_shl1(i8 %x) { 143 ; CHECK-LABEL: @bad_shl1( 144 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 1, [[X:%.*]] 145 ; CHECK-NEXT: ret i8 [[RET]] 146 ; 147 %ret = shl nuw i8 1, %x ; not -1 148 ret i8 %ret 149 } 150 151 define <2 x i8> @bad_shl_vec_nonsplat(<2 x i8> %x) { 152 ; CHECK-LABEL: @bad_shl_vec_nonsplat( 153 ; CHECK-NEXT: [[RET:%.*]] = shl nuw <2 x i8> <i8 -1, i8 1>, [[X:%.*]] 154 ; CHECK-NEXT: ret <2 x i8> [[RET]] 155 ; 156 %ret = shl nuw <2 x i8> <i8 -1, i8 1>, %x 157 ret <2 x i8> %ret 158 } 159 160 ; Bad known bits 161 162 define i8 @bad_knownbits(i8 %x, i8 %y) { 163 ; CHECK-LABEL: @bad_knownbits( 164 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 2 165 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 166 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 167 ; CHECK-NEXT: ret i8 [[RET]] 168 ; 169 %cmp = icmp slt i8 %x, 2 170 tail call void @llvm.assume(i1 %cmp) 171 %ret = shl nuw i8 %x, %y 172 ret i8 %ret 173 } 174 175 define i8 @bad_knownbits_minusoneormore(i8 %x, i8 %y) { 176 ; CHECK-LABEL: @bad_knownbits_minusoneormore( 177 ; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], -2 178 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 179 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 180 ; CHECK-NEXT: ret i8 [[RET]] 181 ; 182 %cmp = icmp sgt i8 %x, -2 183 tail call void @llvm.assume(i1 %cmp) 184 %ret = shl nuw i8 %x, %y 185 ret i8 %ret 186 } 187 188 define i8 @bad_knownbits_zeroorpositive(i8 %x, i8 %y) { 189 ; CHECK-LABEL: @bad_knownbits_zeroorpositive( 190 ; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], -1 191 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 192 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 193 ; CHECK-NEXT: ret i8 [[RET]] 194 ; 195 %cmp = icmp sgt i8 %x, -1 196 tail call void @llvm.assume(i1 %cmp) 197 %ret = shl nuw i8 %x, %y 198 ret i8 %ret 199 } 200 201 define i8 @bad_knownbits_positive(i8 %x, i8 %y) { 202 ; CHECK-LABEL: @bad_knownbits_positive( 203 ; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[X:%.*]], 0 204 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 205 ; CHECK-NEXT: [[RET:%.*]] = shl nuw i8 [[X]], [[Y:%.*]] 206 ; CHECK-NEXT: ret i8 [[RET]] 207 ; 208 %cmp = icmp sgt i8 %x, 0 209 tail call void @llvm.assume(i1 %cmp) 210 %ret = shl nuw i8 %x, %y 211 ret i8 %ret 212 } 213
