[llvm-dev] BSWAP matching in codegen

[Friedman, Eli via llvm-dev]

On 12/8/2016 12:05 PM, Jim Lewis wrote:
>
> >> Are you sure there isn't any test coverage?  As far as I can tell, the tests from 
> https://reviews.llvm.org/rL133503 are still in the tree.
>
> I looked at those, but none of them include the full pattern that 
> decomposes into bswap and rol. I debugged through the X86 bswap.ll 
> test and verified none of those cases make it through MatchBSwapHWord 
> (they get handled in MatchBSwapHWordLow instead).
>

The x86 tests don't, but the ARM tests do: see, for example, test6 in 
test/CodeGen/ARM/rev.ll.  If you compile that for x86, you get the 
expected bswap+rol.

-Eli

-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

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