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; 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
}
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