| ; RUN: opt < %s -instcombine -S | FileCheck %s |
| |
| ; With left shift, the comparison should not be modified. |
| ; CHECK-LABEL: @test_shift_and_cmp_not_changed1( |
| ; CHECK: icmp slt i8 %andp, 32 |
| define i1 @test_shift_and_cmp_not_changed1(i8 %p) #0 { |
| entry: |
| %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. |
| ; CHECK-LABEL: @test_shift_and_cmp_not_changed2( |
| ; CHECK: icmp slt i8 %andp, 32 |
| define i1 @test_shift_and_cmp_not_changed2(i8 %p) #0 { |
| entry: |
| %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. |
| ; CHECK-LABEL: @test_shift_and_cmp_changed1( |
| ; CHECK: %andp = shl i8 %p, 5 |
| ; CHECK-NEXT: %shl = and i8 %andp, -64 |
| ; CHECK-NEXT: %cmp = icmp slt i8 %shl, 32 |
| define i1 @test_shift_and_cmp_changed1(i8 %p, i8 %q) #0 { |
| entry: |
| %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. |
| ; CHECK-LABEL: @test_shift_and_cmp_changed2( |
| ; CHECK: icmp eq i8 %andp, 0 |
| define i1 @test_shift_and_cmp_changed2(i8 %p) #0 { |
| entry: |
| %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. |
| ; CHECK-LABEL: @test_shift_and_cmp_changed3( |
| ; CHECK: icmp slt i8 %andp, 32 |
| define i1 @test_shift_and_cmp_changed3(i8 %p) #0 { |
| entry: |
| %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. |
| ; CHECK-LABEL: @test_shift_and_cmp_changed4( |
| ; CHECK: ret i1 true |
| define i1 @test_shift_and_cmp_changed4(i8 %p) #0 { |
| entry: |
| %shlp = lshr i8 %p, 5 |
| %andp = and i8 %shlp, -64 |
| %cmp = icmp slt i8 %andp, 32 |
| ret i1 %cmp |
| } |
| |