1 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2 ; RUN: opt < %s -instsimplify -S | FileCheck %s 3 4 ; %ret = add nuw i8 %x, C 5 ; nuw means no unsigned wrap, from -1 to 0. 6 ; So if C is -1, %x can only be 0, and the result is always -1. 7 8 define i8 @add_nuw (i8 %x) { 9 ; CHECK-LABEL: @add_nuw( 10 ; CHECK-NEXT: ret i8 -1 11 ; 12 %ret = add nuw i8 %x, -1 13 ; nuw here means that %x can only be 0 14 ret i8 %ret 15 } 16 17 define i8 @add_nuw_nsw (i8 %x) { 18 ; CHECK-LABEL: @add_nuw_nsw( 19 ; CHECK-NEXT: ret i8 -1 20 ; 21 %ret = add nuw nsw i8 %x, -1 22 ; nuw here means that %x can only be 0 23 ret i8 %ret 24 } 25 26 define i8 @add_nuw_commute (i8 %x) { 27 ; CHECK-LABEL: @add_nuw_commute( 28 ; CHECK-NEXT: ret i8 -1 29 ; 30 %ret = add nuw i8 -1, %x ; swapped 31 ; nuw here means that %x can only be 0 32 ret i8 %ret 33 } 34 35 ; ============================================================================ ; 36 ; Positive tests with value range known 37 ; ============================================================================ ; 38 39 declare void @llvm.assume(i1 %cond); 40 41 define i8 @knownbits_allones(i8 %x, i8 %y) { 42 ; CHECK-LABEL: @knownbits_allones( 43 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[Y:%.*]], -2 44 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 45 ; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], [[Y]] 46 ; CHECK-NEXT: ret i8 [[RET]] 47 ; 48 %cmp = icmp slt i8 %y, 254 49 tail call void @llvm.assume(i1 %cmp) 50 %ret = add nuw i8 %x, %y 51 ret i8 %ret 52 } 53 54 ; ============================================================================ ; 55 ; Vectors 56 ; ============================================================================ ; 57 58 define <2 x i8> @add_vec(<2 x i8> %x) { 59 ; CHECK-LABEL: @add_vec( 60 ; CHECK-NEXT: ret <2 x i8> <i8 -1, i8 -1> 61 ; 62 %ret = add nuw <2 x i8> %x, <i8 -1, i8 -1> 63 ret <2 x i8> %ret 64 } 65 66 define <3 x i8> @add_vec_undef(<3 x i8> %x) { 67 ; CHECK-LABEL: @add_vec_undef( 68 ; CHECK-NEXT: ret <3 x i8> <i8 -1, i8 undef, i8 -1> 69 ; 70 %ret = add nuw <3 x i8> %x, <i8 -1, i8 undef, i8 -1> 71 ret <3 x i8> %ret 72 } 73 74 ; ============================================================================ ; 75 ; Negative tests. Should not be folded. 76 ; ============================================================================ ; 77 78 define i8 @bad_add (i8 %x) { 79 ; CHECK-LABEL: @bad_add( 80 ; CHECK-NEXT: [[RET:%.*]] = add i8 [[X:%.*]], -1 81 ; CHECK-NEXT: ret i8 [[RET]] 82 ; 83 %ret = add i8 %x, -1 ; need nuw 84 ret i8 %ret 85 } 86 87 define i8 @bad_add_nsw (i8 %x) { 88 ; CHECK-LABEL: @bad_add_nsw( 89 ; CHECK-NEXT: [[RET:%.*]] = add nsw i8 [[X:%.*]], -1 90 ; CHECK-NEXT: ret i8 [[RET]] 91 ; 92 %ret = add nsw i8 %x, -1 ; need nuw 93 ret i8 %ret 94 } 95 96 ; Second `add` operand is not `-1` constant 97 98 define i8 @bad_add0(i8 %x, i8 %addop2) { 99 ; CHECK-LABEL: @bad_add0( 100 ; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], [[ADDOP2:%.*]] 101 ; CHECK-NEXT: ret i8 [[RET]] 102 ; 103 %ret = add nuw i8 %x, %addop2 104 ret i8 %ret 105 } 106 107 ; Bad constant 108 109 define i8 @bad_add1(i8 %x) { 110 ; CHECK-LABEL: @bad_add1( 111 ; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X:%.*]], 1 112 ; CHECK-NEXT: ret i8 [[RET]] 113 ; 114 %ret = add nuw i8 %x, 1 ; not -1 115 ret i8 %ret 116 } 117 118 define <2 x i8> @bad_add_vec_nonsplat(<2 x i8> %x) { 119 ; CHECK-LABEL: @bad_add_vec_nonsplat( 120 ; CHECK-NEXT: [[RET:%.*]] = add nuw <2 x i8> [[X:%.*]], <i8 -1, i8 1> 121 ; CHECK-NEXT: ret <2 x i8> [[RET]] 122 ; 123 %ret = add nuw <2 x i8> %x, <i8 -1, i8 1> 124 ret <2 x i8> %ret 125 } 126 127 ; Bad known bits 128 129 define i8 @bad_knownbits(i8 %x, i8 %y) { 130 ; CHECK-LABEL: @bad_knownbits( 131 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], -3 132 ; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]]) 133 ; CHECK-NEXT: [[RET:%.*]] = add nuw i8 [[X]], [[Y:%.*]] 134 ; CHECK-NEXT: ret i8 [[RET]] 135 ; 136 %cmp = icmp slt i8 %x, 253 137 tail call void @llvm.assume(i1 %cmp) 138 %ret = add nuw i8 %x, %y 139 ret i8 %ret 140 } 141
