On Tue, 17 Oct 2023 10:56:33 GMT, Andrew Haley <a...@openjdk.org> wrote:
>> src/hotspot/cpu/x86/macroAssembler_x86.cpp line 5169: >> >>> 5167: // Perform a little arithmetic to make sure that denormal >>> 5168: // numbers are handled correctly, i.e. that the "Denormals Are >>> 5169: // Zeros" flag has not been set. >> >> I don't understand what this part is doing. I thought it was simply checking >> so you could log/warn if the unexpected mode was detected. But it seems to >> cause MXCSR to not be restored when there is an issue, where I would expect >> you would always want to restore to overwrite the invalid mode the JNI call >> made. ?? > > If we reach `FAIL`, MXCSR is reloaded from `addr_mxcsr_std()`, restoring > correct IEEE behaviour. That's what RestoreMXCSROnJNICalls is supposed to do, > as far as I can tell. > > But I will take this part out, because there are other flags in MXCSR, so > there is a potential compatibility problem if e.g. the Precision Mask were > set in a JNI call. Misread the code flow. So you were skipping the restore if you didn't think it was needed? The fact the restore was now conditional is what threw me. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/10661#discussion_r1362939998
