On Wed, 12 Oct 2022 17:00:15 GMT, Andrew Haley <a...@openjdk.org> wrote:

>> A bug in GCC causes shared libraries linked with -ffast-math to disable 
>> denormal arithmetic. This breaks Java's floating-point semantics.
>> 
>> The bug is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55522
>> 
>> One solution is to save and restore the floating-point control word around 
>> System.loadLibrary(). This isn't perfect, because some shared library might 
>> load another shared library at runtime, but it's a lot better than what we 
>> do now. 
>> 
>> However, this fix is not complete. `dlopen()` is called from many places in 
>> the JDK. I guess the best thing to do is find and wrap them all. I'd like to 
>> hear people's opinions.
>
> Andrew Haley has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   8295159: DSO created with -ffast-math breaks Java floating-point arithmetic

I found another example while reviewing the assembler sources in the Fedora 
`nacl` package:

* [nacl: Corrupts FPU state on 
x86](https://bugzilla.redhat.com/show_bug.cgi?id=2144809)

The assembler sources look as if they were generated with a high-level 
assembler. That tool apparently does not properly implement the callee-saved 
nature of the floating-point control word.

-------------

PR: https://git.openjdk.org/jdk/pull/10661

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