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| author | Sanjay Patel <spatel@rotateright.com> | 2017-02-08 22:14:11 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-02-08 22:14:11 +0000 |
| commit | a62bc44f6746d0cbcf9c0e1d71c5c32d6a203372 (patch) | |
| tree | 3080b84186bd8f5787b67e1339c524f9e3f3ab2e /llvm/test/Transforms/InstCombine/add.ll | |
| parent | c3a4b282bb787da8cb09d03b490df4aaadb81d33 (diff) | |
| download | bcm5719-llvm-a62bc44f6746d0cbcf9c0e1d71c5c32d6a203372.tar.gz bcm5719-llvm-a62bc44f6746d0cbcf9c0e1d71c5c32d6a203372.zip | |
[InstCombine] add tests to show information-losing add nsw/nuw transforms; NFC
llvm-svn: 294524
Diffstat (limited to 'llvm/test/Transforms/InstCombine/add.ll')
| -rw-r--r-- | llvm/test/Transforms/InstCombine/add.ll | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/llvm/test/Transforms/InstCombine/add.ll b/llvm/test/Transforms/InstCombine/add.ll index 3ea78492470..03b2c3e8571 100644 --- a/llvm/test/Transforms/InstCombine/add.ll +++ b/llvm/test/Transforms/InstCombine/add.ll @@ -244,14 +244,49 @@ define i32 @test19(i1 %C) { ret i32 %V } +; Add of sign bit -> xor of sign bit. + define i32 @test20(i32 %x) { ; CHECK-LABEL: @test20( ; CHECK-NEXT: ret i32 %x ; - %tmp.2 = xor i32 %x, -2147483648 - ;; Add of sign bit -> xor of sign bit. - %tmp.4 = add i32 %tmp.2, -2147483648 - ret i32 %tmp.4 + %y = xor i32 %x, -2147483648 + %z = add nsw i32 %y, -2147483648 + ret i32 %z +} + +define i32 @xor_sign_bit(i32 %x) { +; CHECK-LABEL: @xor_sign_bit( +; CHECK-NEXT: [[ADD:%.*]] = add i32 %x, -2147483606 +; CHECK-NEXT: ret i32 [[ADD]] +; + %xor = xor i32 %x, 2147483648 + %add = add i32 %xor, 42 + ret i32 %add +} + +; Lose no-wrap info by converting to xor? %x is known non-negative +; here, but not after converting to xor. + +define i8 @add_nsw_signbit(i8 %x) { +; CHECK-LABEL: @add_nsw_signbit( +; CHECK-NEXT: [[Y:%.*]] = xor i8 %x, -128 +; CHECK-NEXT: ret i8 [[Y]] +; + %y = add nsw i8 %x, -128 + ret i8 %y +} + +; Lose no-wrap info by converting to xor? %x is known non-negative +; (x < 128 unsigned), but not after converting to xor. + +define i8 @add_nuw_signbit(i8 %x) { +; CHECK-LABEL: @add_nuw_signbit( +; CHECK-NEXT: [[Y:%.*]] = xor i8 %x, -128 +; CHECK-NEXT: ret i8 [[Y]] +; + %y = add nuw i8 %x, 128 + ret i8 %y } define i1 @test21(i32 %x) { |
