llvm-project/llvm/test/Transforms/InstCombine/xor2.ll

; This test makes sure that these instructions are properly eliminated.
;
; RUN: opt < %s -instcombine -S | FileCheck %s

; PR1253
define i1 @test0(i32 %A) {
; CHECK: @test0
; CHECK: %C = icmp slt i32 %A, 0
	%B = xor i32 %A, -2147483648
	%C = icmp sgt i32 %B, -1
	ret i1 %C
}

define i1 @test1(i32 %A) {
; CHECK: @test1
; CHECK: %C = icmp slt i32 %A, 0
	%B = xor i32 %A, 12345
	%C = icmp slt i32 %B, 0
	ret i1 %C
}

; PR1014
define i32 @test2(i32 %tmp1) {
; CHECK:      @test2
; CHECK-NEXT:   and i32 %tmp1, 32
; CHECK-NEXT:   or i32 %ovm, 8 
; CHECK-NEXT:   ret i32
        %ovm = and i32 %tmp1, 32
        %ov3 = add i32 %ovm, 145
        %ov110 = xor i32 %ov3, 153
        ret i32 %ov110
}

define i32 @test3(i32 %tmp1) {
; CHECK:      @test3
; CHECK-NEXT:   and i32 %tmp1, 32
; CHECK-NEXT:   or i32 %ovm, 8
; CHECK-NEXT:   ret i32
  %ovm = or i32 %tmp1, 145 
  %ov31 = and i32 %ovm, 177
  %ov110 = xor i32 %ov31, 153
  ret i32 %ov110
}

define i32 @test4(i32 %A, i32 %B) {
	%1 = xor i32 %A, -1
	%2 = ashr i32 %1, %B
	%3 = xor i32 %2, -1
	ret i32 %3
; CHECK: @test4
; CHECK: %1 = ashr i32 %A, %B
; CHECK: ret i32 %1
}

; defect-2 in rdar://12329730
; (X^C1) >> C2) ^ C3 -> (X>>C2) ^ ((C1>>C2)^C3)
;   where the "X" has more than one use
define i32 @test5(i32 %val1) {
test5:
  %xor = xor i32 %val1, 1234
  %shr = lshr i32 %xor, 8
  %xor1 = xor i32 %shr, 1
  %add = add i32 %xor1, %xor
  ret i32 %add
; CHECK: @test5
; CHECK: lshr i32 %val1, 8
; CHECK: ret
}

; defect-1 in rdar://12329730
; Simplify (X^Y) -> X or Y in the user's context if we know that 
; only bits from X or Y are demanded.
; e.g. the "x ^ 1234" can be optimized into x in the context of "t >> 16".
;  Put in other word, t >> 16 -> x >> 16.
; unsigned foo(unsigned x) { nsigned t = x ^ 1234; ;  return (t >> 16) + t;}
define i32 @test6(i32 %x) {
  %xor = xor i32 %x, 1234
  %shr = lshr i32 %xor, 16
  %add = add i32 %shr, %xor
  ret i32 %add
; CHECK: @test6
; CHECK: lshr i32 %x, 16
; CHECK: ret
}