llvm-project/llvm/test/Transforms/Reassociate/xor_reassoc.ll

;RUN: opt -S -reassociate < %s | FileCheck %s

; ==========================================================================
;
;   Xor reassociation general cases
;  
; ==========================================================================

; (x | c1) ^ (x | c2) => (x & c3) ^ c3, where c3 = c1^c2
;   
define i32 @xor1(i32 %x) {
  %or = or i32 %x, 123
  %or1 = or i32 %x, 456
  %xor = xor i32 %or, %or1
  ret i32 %xor

;CHECK-LABEL: @xor1(
;CHECK: %and.ra = and i32 %x, 435
;CHECK: %xor = xor i32 %and.ra, 435
}

; Test rule : (x & c1) ^ (x & c2) = (x & (c1^c2))
; Real testing case : (x & 123) ^ y ^ (x & 345) => (x & 435) ^ y
define i32 @xor2(i32 %x, i32 %y) {
  %and = and i32 %x, 123
  %xor = xor i32 %and, %y
  %and1 = and i32 %x, 456
  %xor2 = xor i32 %xor, %and1
  ret i32 %xor2

;CHECK-LABEL: @xor2(
;CHECK: %and.ra = and i32 %x, 435
;CHECK: %xor2 = xor i32 %and.ra, %y
}

; Test rule: (x | c1) ^ (x & c2) = (x & c3) ^ c1, where c3 = ~c1 ^ c2
;  c3 = ~c1 ^ c2
define i32 @xor3(i32 %x, i32 %y) {
  %or = or i32 %x, 123
  %xor = xor i32 %or, %y
  %and = and i32 %x, 456
  %xor1 = xor i32 %xor, %and
  ret i32 %xor1

;CHECK-LABEL: @xor3(
;CHECK: %and.ra = and i32 %x, -436
;CHECK: %xor = xor i32 %y, 123
;CHECK: %xor1 = xor i32 %xor, %and.ra
}

; Test rule: (x | c1) ^ c2 = (x & ~c1) ^ (c1 ^ c2)
define i32 @xor4(i32 %x, i32 %y) {
  %and = and i32 %x, -124
  %xor = xor i32 %y, 435
  %xor1 = xor i32 %xor, %and
  ret i32 %xor1
; CHECK-LABEL: @xor4(
; CHECK: %and = and i32 %x, -124
; CHECK: %xor = xor i32 %y, 435
; CHECK: %xor1 = xor i32 %xor, %and
}

; ==========================================================================
;
;  Xor reassociation special cases
;  
; ==========================================================================

; Special case1: 
;  (x | c1) ^ (x & ~c1) = c1
define i32 @xor_special1(i32 %x, i32 %y) {
  %or = or i32 %x, 123
  %xor = xor i32 %or, %y
  %and = and i32 %x, -124
  %xor1 = xor i32 %xor, %and
  ret i32 %xor1
; CHECK-LABEL: @xor_special1(
; CHECK: %xor1 = xor i32 %y, 123
; CHECK: ret i32 %xor1
}

; Special case1: 
;  (x | c1) ^ (x & c1) = x ^ c1
define i32 @xor_special2(i32 %x, i32 %y) {
  %or = or i32 %x, 123
  %xor = xor i32 %or, %y
  %and = and i32 %x, 123
  %xor1 = xor i32 %xor, %and
  ret i32 %xor1
; CHECK-LABEL: @xor_special2(
; CHECK: %xor = xor i32 %y, 123
; CHECK: %xor1 = xor i32 %xor, %x
; CHECK: ret i32 %xor1
}

; (x | c1) ^ (x | c1) => 0
define i32 @xor_special3(i32 %x) {
  %or = or i32 %x, 123
  %or1 = or i32 %x, 123
  %xor = xor i32 %or, %or1
  ret i32 %xor
;CHECK-LABEL: @xor_special3(
;CHECK: ret i32 0
}

; (x & c1) ^ (x & c1) => 0
define i32 @xor_special4(i32 %x) {
  %or = and i32 %x, 123
  %or1 = and i32 123, %x
  %xor = xor i32 %or, %or1
  ret i32 %xor
;CHECK-LABEL: @xor_special4(
;CHECK: ret i32 0
}

; ==========================================================================
;
;  Xor reassociation curtail code size
;  
; ==========================================================================

; (x | c1) ^ (x | c2) => (x & c3) ^ c3
; is enabled if one of operands has multiple uses
;   
define i32 @xor_ra_size1(i32 %x) {
  %or = or i32 %x, 123
  %or1 = or i32 %x, 456
  %xor = xor i32 %or, %or1

  %add = add i32 %xor, %or
  ret i32 %add
;CHECK-LABEL: @xor_ra_size1(
;CHECK: %xor = xor i32 %and.ra, 435
}

; (x | c1) ^ (x | c2) => (x & c3) ^ c3
; is disenabled if bothf operands has multiple uses.
;   
define i32 @xor_ra_size2(i32 %x) {
  %or = or i32 %x, 123
  %or1 = or i32 %x, 456
  %xor = xor i32 %or, %or1

  %add = add i32 %xor, %or
  %add2 = add i32 %add, %or1
  ret i32 %add2

;CHECK-LABEL: @xor_ra_size2(
;CHECK: %or1 = or i32 %x, 456
;CHECK: %xor = xor i32 %or, %or1
}


; ==========================================================================
;
;  Xor reassociation bugs
;  
; ==========================================================================

@xor_bug1_data = external global <{}>, align 4
define void @xor_bug1() {
  %1 = ptrtoint i32* undef to i64
  %2 = xor i64 %1, ptrtoint (<{}>* @xor_bug1_data to i64)
  %3 = and i64 undef, %2
  ret void
}

; The bug was that when the compiler optimize "(x | c1)" ^ "(x & c2)", it may
; swap the two xor-subexpressions if they are not in canoninical order; however,
; when optimizer swaps two sub-expressions, if forgot to swap the cached value
; of c1 and c2 accordingly, hence cause the problem.
;
define i32 @xor_bug2(i32, i32, i32, i32) {
  %5 = mul i32 %0, 123
  %6 = add i32 %2, 24
  %7 = add i32 %1, 8
  %8 = and i32 %1, 3456789
  %9 = or i32 %8,  4567890
  %10 = and i32 %1, 543210987
  %11 = or i32 %1, 891034567
  %12 = and i32 %2, 255
  %13 = xor i32 %9, %10
  %14 = xor i32 %11, %13
  %15 = xor i32 %5, %14
  %16 = and i32 %3, 255
  %17 = xor i32 %16, 42
  %18 = add i32 %6, %7
  %19 = add i32 %18, %12
  %20 = add i32 %19, %15
  ret i32 %20
;CHECK-LABEL: @xor_bug2(
;CHECK: xor i32 %5, 891034567
}