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| author | Owen Anderson <resistor@mac.com> | 2010-12-23 23:56:24 +0000 |
|---|---|---|
| committer | Owen Anderson <resistor@mac.com> | 2010-12-23 23:56:24 +0000 |
| commit | ec3953ff95c6106185fc6509175b86cbdf3958f6 (patch) | |
| tree | e01b7ec9d5c813c12d33fb58095a5fd80bdeb3d9 /test/Transforms/InstCombine/shift.ll | |
| parent | e4a2dd2f1ada7acea92df156ebaf8a45a17e139d (diff) | |
| download | llvm-ec3953ff95c6106185fc6509175b86cbdf3958f6.tar.gz llvm-ec3953ff95c6106185fc6509175b86cbdf3958f6.tar.bz2 llvm-ec3953ff95c6106185fc6509175b86cbdf3958f6.tar.xz | |
When determining if we can fold (x >> C1) << C2, the bits that we need to verify are zero
are not the low bits of x, but the bits that WILL be the low bits after the operation completes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122529 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms/InstCombine/shift.ll')
| -rw-r--r-- | test/Transforms/InstCombine/shift.ll | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/shift.ll b/test/Transforms/InstCombine/shift.ll index 8d1c82991f..4f6939d632 100644 --- a/test/Transforms/InstCombine/shift.ll +++ b/test/Transforms/InstCombine/shift.ll @@ -452,3 +452,22 @@ define i32 @test38(i32 %x) nounwind readnone { ; CHECK-NEXT: ret i32 } +; <rdar://problem/8756731> +; CHECK: @test39 +define i8 @test39(i32 %a0) { +entry: + %tmp4 = trunc i32 %a0 to i8 +; CHECK: and i8 %tmp49, 64 + %tmp5 = shl i8 %tmp4, 5 + %tmp48 = and i8 %tmp5, 32 + %tmp49 = lshr i8 %tmp48, 5 + %tmp50 = mul i8 %tmp49, 64 + %tmp51 = xor i8 %tmp50, %tmp5 +; CHECK: and i8 %0, 16 + %tmp52 = and i8 %tmp51, -128 + %tmp53 = lshr i8 %tmp52, 7 + %tmp54 = mul i8 %tmp53, 16 + %tmp55 = xor i8 %tmp54, %tmp51 +; CHECK: ret i8 %tmp551 + ret i8 %tmp55 +} |