RFR: 8313882: Fix -Wconversion warnings in runtime code [v2]

[Dean Long]

On Wed, 9 Aug 2023 00:24:30 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> src/hotspot/share/runtime/sharedRuntime.cpp line 2348:
>> 
>>> 2346:     double sum = 0;
>>> 2347:     double weighted_sum = 0;
>>> 2348:     for (int i = 0; i <= n; i++) { sum += (double)histo[i]; weighted_sum += (double)(i*histo[i]); }
>> 
>> So hist is a uint64_t*, why can't we make sum and weighted_sum just uint64_t?
>
> I think there were less casts this way, since sum and weighted sum had to be turned into double more than histo[i], but it does make more sense to use int for summing the numbers, and cast to double for printing.

I don't know how big these values are, but if they were large then uint64_t sum could overflow.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15177#discussion_r1287844731