[llvm] r306801 - [InstCombine] Add test cases to demonstrate failure to fold (a | b) ^ (~a | ~b) --> ~(a ^ b) and its commuted variants.
Craig Topper via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 30 00:37:43 PDT 2017
Author: ctopper
Date: Fri Jun 30 00:37:42 2017
New Revision: 306801
URL: http://llvm.org/viewvc/llvm-project?rev=306801&view=rev
Log:
[InstCombine] Add test cases to demonstrate failure to fold (a | b) ^ (~a | ~b) --> ~(a ^ b) and its commuted variants.
Modified:
llvm/trunk/test/Transforms/InstCombine/and-or-not.ll
llvm/trunk/test/Transforms/InstCombine/or-xor.ll
Modified: llvm/trunk/test/Transforms/InstCombine/and-or-not.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/and-or-not.ll?rev=306801&r1=306800&r2=306801&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/and-or-not.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/and-or-not.ll Fri Jun 30 00:37:42 2017
@@ -564,3 +564,87 @@ define i32 @or_to_nxor_multiuse(i32 %a,
%mul2 = mul i32 %mul1, %or2
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
+}
Modified: llvm/trunk/test/Transforms/InstCombine/or-xor.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/or-xor.ll?rev=306801&r1=306800&r2=306801&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/or-xor.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/or-xor.ll Fri Jun 30 00:37:42 2017
@@ -344,3 +344,71 @@ define i8 @test18(i8 %A, i8 %B) {
%res = mul i8 %or, %xor2 ; to increase the use count for the xor
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
+}
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