1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: opt < %s -instcombine -S | FileCheck %s 3 4; With left shift, the comparison should not be modified. 5define i1 @test_shift_and_cmp_not_changed1(i8 %p) { 6; CHECK-LABEL: @test_shift_and_cmp_not_changed1( 7; CHECK-NEXT: [[SHLP:%.*]] = shl i8 %p, 5 8; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 9; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 10; CHECK-NEXT: ret i1 [[CMP]] 11; 12 %shlp = shl i8 %p, 5 13 %andp = and i8 %shlp, -64 14 %cmp = icmp slt i8 %andp, 32 15 ret i1 %cmp 16} 17 18; With arithmetic right shift, the comparison should not be modified. 19define i1 @test_shift_and_cmp_not_changed2(i8 %p) { 20; CHECK-LABEL: @test_shift_and_cmp_not_changed2( 21; CHECK-NEXT: [[SHLP:%.*]] = ashr i8 %p, 5 22; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 23; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 24; CHECK-NEXT: ret i1 [[CMP]] 25; 26 %shlp = ashr i8 %p, 5 27 %andp = and i8 %shlp, -64 28 %cmp = icmp slt i8 %andp, 32 29 ret i1 %cmp 30} 31 32; This should simplify functionally to the left shift case. 33; The extra input parameter should be optimized away. 34define i1 @test_shift_and_cmp_changed1(i8 %p, i8 %q) { 35; CHECK-LABEL: @test_shift_and_cmp_changed1( 36; CHECK-NEXT: [[ANDP:%.*]] = shl i8 %p, 5 37; CHECK-NEXT: [[SHL:%.*]] = and i8 [[ANDP]], -64 38; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[SHL]], 32 39; CHECK-NEXT: ret i1 [[CMP]] 40; 41 %andp = and i8 %p, 6 42 %andq = and i8 %q, 8 43 %or = or i8 %andq, %andp 44 %shl = shl i8 %or, 5 45 %ashr = ashr i8 %shl, 5 46 %cmp = icmp slt i8 %ashr, 1 47 ret i1 %cmp 48} 49 50define <2 x i1> @test_shift_and_cmp_changed1_vec(<2 x i8> %p, <2 x i8> %q) { 51; CHECK-LABEL: @test_shift_and_cmp_changed1_vec( 52; CHECK-NEXT: [[ANDP:%.*]] = shl <2 x i8> [[P:%.*]], <i8 5, i8 5> 53; CHECK-NEXT: [[SHL:%.*]] = and <2 x i8> [[ANDP]], <i8 -64, i8 -64> 54; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> [[SHL]], <i8 32, i8 32> 55; CHECK-NEXT: ret <2 x i1> [[CMP]] 56; 57 %andp = and <2 x i8> %p, <i8 6, i8 6> 58 %andq = and <2 x i8> %q, <i8 8, i8 8> 59 %or = or <2 x i8> %andq, %andp 60 %shl = shl <2 x i8> %or, <i8 5, i8 5> 61 %ashr = ashr <2 x i8> %shl, <i8 5, i8 5> 62 %cmp = icmp slt <2 x i8> %ashr, <i8 1, i8 1> 63 ret <2 x i1> %cmp 64} 65 66; Unsigned compare allows a transformation to compare against 0. 67define i1 @test_shift_and_cmp_changed2(i8 %p) { 68; CHECK-LABEL: @test_shift_and_cmp_changed2( 69; CHECK-NEXT: [[ANDP:%.*]] = and i8 %p, 6 70; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[ANDP]], 0 71; CHECK-NEXT: ret i1 [[CMP]] 72; 73 %shlp = shl i8 %p, 5 74 %andp = and i8 %shlp, -64 75 %cmp = icmp ult i8 %andp, 32 76 ret i1 %cmp 77} 78 79define <2 x i1> @test_shift_and_cmp_changed2_vec(<2 x i8> %p) { 80; CHECK-LABEL: @test_shift_and_cmp_changed2_vec( 81; CHECK-NEXT: [[ANDP:%.*]] = and <2 x i8> %p, <i8 6, i8 6> 82; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i8> [[ANDP]], zeroinitializer 83; CHECK-NEXT: ret <2 x i1> [[CMP]] 84; 85 %shlp = shl <2 x i8> %p, <i8 5, i8 5> 86 %andp = and <2 x i8> %shlp, <i8 -64, i8 -64> 87 %cmp = icmp ult <2 x i8> %andp, <i8 32, i8 32> 88 ret <2 x i1> %cmp 89} 90 91; nsw on the shift should not affect the comparison. 92define i1 @test_shift_and_cmp_changed3(i8 %p) { 93; CHECK-LABEL: @test_shift_and_cmp_changed3( 94; CHECK-NEXT: [[SHLP:%.*]] = shl nsw i8 %p, 5 95; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 96; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 97; CHECK-NEXT: ret i1 [[CMP]] 98; 99 %shlp = shl nsw i8 %p, 5 100 %andp = and i8 %shlp, -64 101 %cmp = icmp slt i8 %andp, 32 102 ret i1 %cmp 103} 104 105; Logical shift right allows a return true because the 'and' guarantees no bits are set. 106define i1 @test_shift_and_cmp_changed4(i8 %p) { 107; CHECK-LABEL: @test_shift_and_cmp_changed4( 108; CHECK-NEXT: ret i1 true 109; 110 %shlp = lshr i8 %p, 5 111 %andp = and i8 %shlp, -64 112 %cmp = icmp slt i8 %andp, 32 113 ret i1 %cmp 114} 115 116