; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instcombine -S | FileCheck %s ; With left shift, the comparison should not be modified. define i1 @test_shift_and_cmp_not_changed1(i8 %p) #0 { ; CHECK-LABEL: @test_shift_and_cmp_not_changed1( ; CHECK-NEXT: [[SHLP:%.*]] = shl i8 %p, 5 ; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 ; CHECK-NEXT: ret i1 [[CMP]] ; %shlp = shl i8 %p, 5 %andp = and i8 %shlp, -64 %cmp = icmp slt i8 %andp, 32 ret i1 %cmp } ; With arithmetic right shift, the comparison should not be modified. define i1 @test_shift_and_cmp_not_changed2(i8 %p) #0 { ; CHECK-LABEL: @test_shift_and_cmp_not_changed2( ; CHECK-NEXT: [[SHLP:%.*]] = ashr i8 %p, 5 ; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 ; CHECK-NEXT: ret i1 [[CMP]] ; %shlp = ashr i8 %p, 5 %andp = and i8 %shlp, -64 %cmp = icmp slt i8 %andp, 32 ret i1 %cmp } ; This should simplify functionally to the left shift case. ; The extra input parameter should be optimized away. define i1 @test_shift_and_cmp_changed1(i8 %p, i8 %q) #0 { ; CHECK-LABEL: @test_shift_and_cmp_changed1( ; CHECK-NEXT: [[ANDP:%.*]] = shl i8 %p, 5 ; CHECK-NEXT: [[SHL:%.*]] = and i8 [[ANDP]], -64 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[SHL]], 32 ; CHECK-NEXT: ret i1 [[CMP]] ; %andp = and i8 %p, 6 %andq = and i8 %q, 8 %or = or i8 %andq, %andp %shl = shl i8 %or, 5 %ashr = ashr i8 %shl, 5 %cmp = icmp slt i8 %ashr, 1 ret i1 %cmp } ; Unsigned compare allows a transformation to compare against 0. define i1 @test_shift_and_cmp_changed2(i8 %p) #0 { ; CHECK-LABEL: @test_shift_and_cmp_changed2( ; CHECK-NEXT: [[ANDP:%.*]] = and i8 %p, 6 ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[ANDP]], 0 ; CHECK-NEXT: ret i1 [[CMP]] ; %shlp = shl i8 %p, 5 %andp = and i8 %shlp, -64 %cmp = icmp ult i8 %andp, 32 ret i1 %cmp } ; nsw on the shift should not affect the comparison. define i1 @test_shift_and_cmp_changed3(i8 %p) #0 { ; CHECK-LABEL: @test_shift_and_cmp_changed3( ; CHECK-NEXT: [[SHLP:%.*]] = shl nsw i8 %p, 5 ; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64 ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32 ; CHECK-NEXT: ret i1 [[CMP]] ; %shlp = shl nsw i8 %p, 5 %andp = and i8 %shlp, -64 %cmp = icmp slt i8 %andp, 32 ret i1 %cmp } ; Logical shift right allows a return true because the 'and' guarantees no bits are set. define i1 @test_shift_and_cmp_changed4(i8 %p) #0 { ; CHECK-LABEL: @test_shift_and_cmp_changed4( ; CHECK-NEXT: ret i1 true ; %shlp = lshr i8 %p, 5 %andp = and i8 %shlp, -64 %cmp = icmp slt i8 %andp, 32 ret i1 %cmp }