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type_info: avoid gcc-7 -Wsign-conversion warning

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On GCC 7.5.0, the current `uvw::internal::fnv1a()` function throws a
`Wsign-conversion` warning, despite us having an explicit cast.

```
src/uvw/type_info.hpp: In function 'constexpr uint32_t uvw::internal::fnv1a(const char*)':
src/uvw/type_info.hpp:24:26: warning: conversion to 'unsigned int' from 'char' may change the sign of the result [-Wsign-conversion]
         value = (value ^ static_cast<std::uint32_t>(curr_val)) * prime;
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

This seems to be a bug in GCC 7.5.0, since newer versions of GCC are
fine with it. Moving the cast to another line fixes the warning, and it
should all be compiled down to the same machine code anyway.
This commit is contained in:
Alois Klink 2023-08-23 15:42:28 +01:00
parent 36b586f7d3
commit fc828e5b3e
1 changed files with 2 additions and 1 deletions
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3
src/uvw/type_info.hpp
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@ -20,7 +20,8 @@ namespace internal {
auto value = offset; auto value = offset;
while(*curr != 0) { while(*curr != 0) {
value = (value ^ static_cast<std::uint32_t>(*(curr++))) * prime; auto curr_val_int = static_cast<std::uint32_t>(*(curr++));
value = (value ^ curr_val_int) * prime;
} }
return value; return value;