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[InstCombine] Add test cases to demonstrate failure to fold (a | b) ^ (~a | ~b) --> ~(a ^ b) and its commuted variants. 

llvm-svn: 306801
This commit is contained in:
Craig Topper 2017-06-30 07:37:42 +00:00
parent 880bf82685
commit 97cd0173b9
2 changed files with 152 additions and 0 deletions
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84
llvm/test/Transforms/InstCombine/and-or-not.ll
View File

@ -564,3 +564,87 @@ define i32 @or_to_nxor_multiuse(i32 %a, i32 %b) {
%mul2 = mul i32 %mul1, %or2 %mul2 = mul i32 %mul1, %or2
ret i32 %mul2 ret i32 %mul2
} }
; (a | b) ^ (~a | ~b) --> ~(a ^ b)
define i32 @xor_to_xnor1(float %fa, float %fb) {
; CHECK-LABEL: @xor_to_xnor1(
; CHECK-NEXT: [[A:%.*]] = fptosi float [[FA:%.*]] to i32
; CHECK-NEXT: [[B:%.*]] = fptosi float [[FB:%.*]] to i32
; CHECK-NEXT: [[OR1:%.*]] = or i32 [[A]], [[B]]
; CHECK-NEXT: [[OR2_DEMORGAN:%.*]] = and i32 [[A]], [[B]]
; CHECK-NEXT: [[OR2:%.*]] = xor i32 [[OR2_DEMORGAN]], -1
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR1]], [[OR2]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%a = fptosi float %fa to i32
%b = fptosi float %fb to i32
%nota = xor i32 %a, -1
%notb = xor i32 %b, -1
%or1 = or i32 %a, %b
%or2 = or i32 %nota, %notb
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; (a | b) ^ (~b | ~a) --> ~(a ^ b)
define i32 @xor_to_xnor2(float %fa, float %fb) {
; CHECK-LABEL: @xor_to_xnor2(
; CHECK-NEXT: [[A:%.*]] = fptosi float [[FA:%.*]] to i32
; CHECK-NEXT: [[B:%.*]] = fptosi float [[FB:%.*]] to i32
; CHECK-NEXT: [[OR1:%.*]] = or i32 [[A]], [[B]]
; CHECK-NEXT: [[OR2_DEMORGAN:%.*]] = and i32 [[B]], [[A]]
; CHECK-NEXT: [[OR2:%.*]] = xor i32 [[OR2_DEMORGAN]], -1
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR1]], [[OR2]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%a = fptosi float %fa to i32
%b = fptosi float %fb to i32
%nota = xor i32 %a, -1
%notb = xor i32 %b, -1
%or1 = or i32 %a, %b
%or2 = or i32 %notb, %nota
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; (~a | ~b) ^ (a | b) --> ~(a ^ b)
define i32 @xor_to_xnor3(float %fa, float %fb) {
; CHECK-LABEL: @xor_to_xnor3(
; CHECK-NEXT: [[A:%.*]] = fptosi float [[FA:%.*]] to i32
; CHECK-NEXT: [[B:%.*]] = fptosi float [[FB:%.*]] to i32
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and i32 [[A]], [[B]]
; CHECK-NEXT: [[OR1:%.*]] = xor i32 [[OR1_DEMORGAN]], -1
; CHECK-NEXT: [[OR2:%.*]] = or i32 [[A]], [[B]]
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR2]], [[OR1]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%a = fptosi float %fa to i32
%b = fptosi float %fb to i32
%nota = xor i32 %a, -1
%notb = xor i32 %b, -1
%or1 = or i32 %nota, %notb
%or2 = or i32 %a, %b
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; (~a | ~b) ^ (b | a) --> ~(a ^ b)
define i32 @xor_to_xnor4(float %fa, float %fb) {
; CHECK-LABEL: @xor_to_xnor4(
; CHECK-NEXT: [[A:%.*]] = fptosi float [[FA:%.*]] to i32
; CHECK-NEXT: [[B:%.*]] = fptosi float [[FB:%.*]] to i32
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and i32 [[A]], [[B]]
; CHECK-NEXT: [[OR1:%.*]] = xor i32 [[OR1_DEMORGAN]], -1
; CHECK-NEXT: [[OR2:%.*]] = or i32 [[B]], [[A]]
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR2]], [[OR1]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%a = fptosi float %fa to i32
%b = fptosi float %fb to i32
%nota = xor i32 %a, -1
%notb = xor i32 %b, -1
%or1 = or i32 %nota, %notb
%or2 = or i32 %b, %a
%xor = xor i32 %or1, %or2
ret i32 %xor
}

68
llvm/test/Transforms/InstCombine/or-xor.ll
View File

@ -344,3 +344,71 @@ define i8 @test18(i8 %A, i8 %B) {
%res = mul i8 %or, %xor2 ; to increase the use count for the xor %res = mul i8 %or, %xor2 ; to increase the use count for the xor
ret i8 %res ret i8 %res
} }
; ((x | y) ^ (~x | ~y)) -> ~(x ^ y)
define i32 @test19(i32 %x, i32 %y) {
; CHECK-LABEL: @test19(
; CHECK-NEXT: [[OR1:%.*]] = or i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[OR2_DEMORGAN:%.*]] = and i32 [[X]], [[Y]]
; CHECK-NEXT: [[OR2:%.*]] = xor i32 [[OR2_DEMORGAN]], -1
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR1]], [[OR2]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
%notx = xor i32 %x, -1
%or1 = or i32 %x, %y
%or2 = or i32 %notx, %noty
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; ((x | y) ^ (~y | ~x)) -> ~(x ^ y)
define i32 @test20(i32 %x, i32 %y) {
; CHECK-LABEL: @test20(
; CHECK-NEXT: [[OR1:%.*]] = or i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[OR2_DEMORGAN:%.*]] = and i32 [[Y]], [[X]]
; CHECK-NEXT: [[OR2:%.*]] = xor i32 [[OR2_DEMORGAN]], -1
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR1]], [[OR2]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
%notx = xor i32 %x, -1
%or1 = or i32 %x, %y
%or2 = or i32 %noty, %notx
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; ((~x | ~y) ^ (x | y)) -> ~(x ^ y)
define i32 @test21(i32 %x, i32 %y) {
; CHECK-LABEL: @test21(
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[OR1:%.*]] = xor i32 [[OR1_DEMORGAN]], -1
; CHECK-NEXT: [[OR2:%.*]] = or i32 [[X]], [[Y]]
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR2]], [[OR1]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
%notx = xor i32 %x, -1
%or1 = or i32 %notx, %noty
%or2 = or i32 %x, %y
%xor = xor i32 %or1, %or2
ret i32 %xor
}
; ((~x | ~y) ^ (y | x)) -> ~(x ^ y)
define i32 @test22(i32 %x, i32 %y) {
; CHECK-LABEL: @test22(
; CHECK-NEXT: [[OR1_DEMORGAN:%.*]] = and i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[OR1:%.*]] = xor i32 [[OR1_DEMORGAN]], -1
; CHECK-NEXT: [[OR2:%.*]] = or i32 [[Y]], [[X]]
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[OR2]], [[OR1]]
; CHECK-NEXT: ret i32 [[XOR]]
;
%noty = xor i32 %y, -1
%notx = xor i32 %x, -1
%or1 = or i32 %notx, %noty
%or2 = or i32 %y, %x
%xor = xor i32 %or1, %or2
ret i32 %xor
}