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| author | Craig Topper <craig.topper@intel.com> | 2017-07-02 01:15:51 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2017-07-02 01:15:51 +0000 |
| commit | f60ab47098c4768014ac4b761a6df41cb0cc0d5e (patch) | |
| tree | dc46dfe4f3fb5897153abf2e13f5b738797d2ce9 /llvm/test/Transforms/InstCombine/or-xor.ll | |
| parent | e3f7dda1fb57e8810e4757dea0fed3917666ef24 (diff) | |
| download | bcm5719-llvm-f60ab47098c4768014ac4b761a6df41cb0cc0d5e.tar.gz bcm5719-llvm-f60ab47098c4768014ac4b761a6df41cb0cc0d5e.zip | |
[InstCombine] Fold (a | b) ^ (~a | ~b) --> ~(a ^ b) and (a & b) ^ (~a & ~b) --> ~(a ^ b)
Summary:
I came across this while thinking about what would happen if one of the operands in this xor pattern was itself a inverted (A & ~B) ^ (~A & B)-> (A^B).
The patterns here assume that the (~a | ~b) will be demorganed to ~(a & b) first. Though I wonder if there's a multiple use case that would prevent the demorgan.
Reviewers: spatel
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D34870
llvm-svn: 306967
Diffstat (limited to 'llvm/test/Transforms/InstCombine/or-xor.ll')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/or-xor.ll | 24 |
1 files changed, 8 insertions, 16 deletions
diff --git a/llvm/test/Transforms/InstCombine/or-xor.ll b/llvm/test/Transforms/InstCombine/or-xor.ll index 2164f0df8d2..947971c6c83 100644 --- a/llvm/test/Transforms/InstCombine/or-xor.ll +++ b/llvm/test/Transforms/InstCombine/or-xor.ll @@ -348,10 +348,8 @@ define i8 @test18(i8 %A, i8 %B) { ; ((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: [[TMP1:%.*]] = xor i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1 ; CHECK-NEXT: ret i32 [[XOR]] ; %noty = xor i32 %y, -1 @@ -365,10 +363,8 @@ define i32 @test19(i32 %x, i32 %y) { ; ((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: [[TMP1:%.*]] = xor i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1 ; CHECK-NEXT: ret i32 [[XOR]] ; %noty = xor i32 %y, -1 @@ -382,10 +378,8 @@ define i32 @test20(i32 %x, i32 %y) { ; ((~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: [[TMP1:%.*]] = xor i32 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1 ; CHECK-NEXT: ret i32 [[XOR]] ; %noty = xor i32 %y, -1 @@ -399,10 +393,8 @@ define i32 @test21(i32 %x, i32 %y) { ; ((~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: [[TMP1:%.*]] = xor i32 [[Y:%.*]], [[X:%.*]] +; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[TMP1]], -1 ; CHECK-NEXT: ret i32 [[XOR]] ; %noty = xor i32 %y, -1 |
