[PATCH] D85225: [Target][AArch64] Allow for char as int8_t in AArch64AsmParser.cpp

[Rainer Orth via Phabricator via llvm-commits]

ro added inline comments.


================
Comment at: llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp:859
+    bool IsByte = std::is_same<int8_t, std::make_signed_t<T>>::value ||
+                  std::is_same<signed char, std::make_signed_t<T>>::value;
     if (auto ShiftedImm = getShiftedVal<8>())
----------------
paulwalker-arm wrote:
> Perhaps a naive question but are there any concerns about "signed char" being bigger than a byte on any systems?
> 
> The commit message suggests its the make_signed that is the problem so I'm wondering if instead adding "std::is_same<int8_t, T>::value" would also work?
> Perhaps a naive question but are there any concerns about "signed char" being bigger than a byte on any systems?

There shouldn't be: `sizeof(char/unsigned char/signed char)` is guaranteed to be `1` by C11, 6.5.3.4.

> The commit message suggests its the make_signed that is the problem so I'm wondering if instead adding "std::is_same<int8_t, T>::value" would also work?

At least if have found no case where `T` wasn't a signed type.  OTOH maybe s simple `sizeof(T) == 1` is enough?


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  https://reviews.llvm.org/D85225/new/

https://reviews.llvm.org/D85225