https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88113
Bug ID: 88113
Summary: Woverflow warning in memory_resource.cc (struct
bitset), for 16-bit size_t
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: jozef.l at mittosystems dot com
Target Milestone: ---
In the definition of struct bitset in
libstdc++-v3/src/c++17/memory_resource.cc, "size_type" (using uint32_t), and
size_t appear to be used interchangeably.
However, for some targets size_t != uint32_t, for example msp430-elf uses
uint16_t for size_t in the small memory model, and "unsigned __int20" in the
large memory model.
This results in a warning:
> ../../../../../libstdc++-v3/src/c++17/memory_resource.cc: In static member
> function 'static constexpr std::size_t
> std::pmr::{anonymous}::bitset::max_blocks_per_chunk()':
> ../../../../../libstdc++-v3/src/c++17/memory_resource.cc:401:39: warning:
> conversion from 'long long unsigned int' to 'std::size_t' {aka 'unsigned
> int'} changes value from '524287' to '65535' [-Woverflow]
> 401 | { return (1ull << _S_size_digits) - 1; }
> | ~~~~~~~~~~~~~~~~~~~~~~~~~^~~
"_S_size_digits" uses "size_type" to calculate the number of digits, whilst
"max_blocks_per_chunk" returns "size_t".
