On Wed, 4 Dec 2024 09:42:59 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> Found this while cleaning up x86_32 code for removal. >> >> In our current code there is a block added by >> [JDK-8076373](https://bugs.openjdk.org/browse/JDK-8076373): >> https://github.com/openjdk/jdk/blob/3b21a298c29d88720f6bfb2dc1f3305b6a3db307/src/hotspot/share/compiler/compileBroker.cpp#L1451-L1473 >> >> Ostensibly, that block is for x86_32 handling of signalling NaNs -- x87 FPU >> has a peculiarity with them. See other funky bugs we seen with it: >> [JDK-8285985](https://bugs.openjdk.org/browse/JDK-8285985), >> [JDK-8293991](https://bugs.openjdk.org/browse/JDK-8293991). >> >> But the way current block is coded, it is enabled for X86 wholesale, which >> also means x86_64! In fact, it is likely even worse on x86_64, because the >> related "fast" entries are generated only for x86_32: >> https://github.com/openjdk/jdk/blob/3b21a298c29d88720f6bfb2dc1f3305b6a3db307/src/hotspot/share/interpreter/templateInterpreterGenerator.cpp#L493-L502 >> >> This can be solved by checking `IA32` instead of `X86`. This block would be >> gone completely once we remove x86_32 port. Meanwhile, we can make it right >> by x86_64, and make eventual x86_32 removal less confusing. This issue seems >> to only affect the compilation of native methods, while most of the hot code >> is riding on compiler intrinsics. I'll put performance data in comments. >> >> Additional testing: >> - [x] Linux x86_64 server fastdebug, `all` > > Aleksey Shipilev has updated the pull request incrementally with one > additional commit since the last revision: > > Disable IR tests on IA32 I just launched testing, I don't think @vnkozlov did that already. Better to hold off until RDP1 / JDK25 fork anyway. test/hotspot/jtreg/compiler/c2/irTests/TestFPConversion.java line 33: > 31: * @summary Test that code generation for FP conversion works as intended > 32: * @library /test/lib / > 33: * @requires os.arch != "x86" & os.arch != "i386" It would have been preferrable to add this to the IR rule, so the test still runs elsewhere. What about `aarch64`? ------------- PR Review: https://git.openjdk.org/jdk/pull/22446#pullrequestreview-2478784069 PR Review Comment: https://git.openjdk.org/jdk/pull/22446#discussion_r1869595147
