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| author | Roman Lebedev <lebedev.ri@gmail.com> | 2020-02-25 17:14:43 +0300 |
|---|---|---|
| committer | Hans Wennborg <hans@chromium.org> | 2020-02-27 13:45:21 +0100 |
| commit | ac293ede5e62cfc569f2d5d8f4667e6188afced0 (patch) | |
| tree | 9569954a8453a7af1e98f9283da7d8ac386da131 | |
| parent | f115a88191c3dc80c5140fbbf63f74ca77fcc74b (diff) | |
| download | bcm5719-llvm-ac293ede5e62cfc569f2d5d8f4667e6188afced0.tar.gz bcm5719-llvm-ac293ede5e62cfc569f2d5d8f4667e6188afced0.zip | |
[NFC][InstCombine] Add shift amount reassociation in bittest miscompile example from PR44802
https://bugs.llvm.org/show_bug.cgi?id=44802
(cherry picked from commit 6f807ca00d951d3e74f7ea4fe1daa8e3560f4c0d)
| -rw-r--r-- | llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll index 27224705929..0386d8042f9 100644 --- a/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll +++ b/llvm/test/Transforms/InstCombine/shift-amount-reassociation-in-bittest.ll @@ -687,3 +687,20 @@ entry: %tobool = icmp ne i16 %and, 0 ret i1 %tobool } + +; FIXME: this is a miscompile. We should not transform this. +; See https://bugs.llvm.org/show_bug.cgi?id=44802 +define i1 @pr44802(i3 %a, i3 %x, i3 %y) { +; CHECK-LABEL: @pr44802( +; CHECK-NEXT: [[TMP1:%.*]] = and i3 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i3 [[TMP1]], 0 +; CHECK-NEXT: ret i1 [[TMP2]] +; + %t0 = icmp ne i3 %a, 0 + %t1 = zext i1 %t0 to i3 + %t2 = lshr i3 %x, %t1 + %t3 = shl i3 %y, %t1 + %t4 = and i3 %t2, %t3 + %t5 = icmp ne i3 %t4, 0 + ret i1 %t5 +} |
