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| author | Nick Lewycky <nicholas@mxc.ca> | 2008-08-17 07:34:14 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2008-08-17 07:34:14 +0000 |
| commit | 7899269b75c41ea5bfabde8f6a824881dd4e3c51 (patch) | |
| tree | b4fe34a4140add6b174e658986207d993bf055b6 /test | |
| parent | 270b17939fb084439bf7641c720e4cbb9f70e080 (diff) | |
| download | external_llvm-7899269b75c41ea5bfabde8f6a824881dd4e3c51.zip external_llvm-7899269b75c41ea5bfabde8f6a824881dd4e3c51.tar.gz external_llvm-7899269b75c41ea5bfabde8f6a824881dd4e3c51.tar.bz2 | |
Xor'ing both sides of icmp by sign-bit is equivalent to swapping signedness of
the predicate.
Also, make this optz'n apply in more cases where it's safe to do so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54876 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test')
| -rw-r--r-- | test/Transforms/InstCombine/2008-08-17-ICmpXorSignbit.ll | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/2008-08-17-ICmpXorSignbit.ll b/test/Transforms/InstCombine/2008-08-17-ICmpXorSignbit.ll new file mode 100644 index 0000000..68ed327 --- /dev/null +++ b/test/Transforms/InstCombine/2008-08-17-ICmpXorSignbit.ll @@ -0,0 +1,22 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep -v xor + +define i1 @test1(i8 %x, i8 %y) { + %X = xor i8 %x, 128 + %Y = xor i8 %y, 128 + %tmp = icmp slt i8 %X, %Y + ret i1 %tmp +} + +define i1 @test2(i8 %x, i8 %y) { + %X = xor i8 %x, 128 + %Y = xor i8 %y, 128 + %tmp = icmp ult i8 %X, %Y + ret i1 %tmp +} + +define i1 @test3(i8 %x) { + %X = xor i8 %x, 128 + %tmp = icmp uge i8 %X, 15 + ret i1 %tmp +} + |