On Fri, 6 Jun 2025 19:22:10 GMT, Coleen Phillimore <cole...@openjdk.org> wrote:
>> Radim Vansa has updated the pull request incrementally with two additional
>> commits since the last revision:
>>
>> - Add more comments
>> - Disable search table with dynamic CDS
>
> src/hotspot/share/utilities/packedTable.cpp line 83:
>
>> 81: assert(mid >= low && mid < high, "integer overflow?");
>> 82: uint64_t element = read_element(data, length, _element_bytes * mid);
>> 83: uint32_t key = element & _key_mask;
>
> All this casting is hard to follow so I added this at the beginning of the
> file:
>
> #ifndef _WIN32
> #pragma GCC diagnostic warning "-Wconversion"
> #endif
>
> and this line, 102, and 87 complain:
>
>
> warning: conversion from 'uint64_t' {aka 'long unsigned int'} to 'uint32_t'
> {aka 'unsigned int'} may change value [-Wconversion]
> 87 | uint32_t key = element & _key_mask;
> | ~~~~~~~~^~~~~~~~~~~
>
>
> If the value is okay to cast to uint32_t, which I believe it is, use
> checked_cast<uint32_t> from checkedCast.hpp.
We cannot use `checked_cast`, because `element` can contain higher-order bits;
but we want to ignore those. I can do an explicit `static_cast` and add a
comment.
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PR Review Comment: https://git.openjdk.org/jdk/pull/24847#discussion_r2135343070
