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From: Michael Meissner <meissner@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/meissner/heads/work107)] Update ChangeLog.meissner Date: Mon, 23 Jan 2023 21:17:33 +0000 (GMT) [thread overview] Message-ID: <20230123211733.8FACC3858C60@sourceware.org> (raw) https://gcc.gnu.org/g:cd50ffa67ba91798309338dab699b208dc21d460 commit cd50ffa67ba91798309338dab699b208dc21d460 Author: Michael Meissner <meissner@linux.ibm.com> Date: Fri Jan 20 16:02:27 2023 -0500 Update ChangeLog.meissner Diff: --- gcc/ChangeLog.meissner | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/gcc/ChangeLog.meissner b/gcc/ChangeLog.meissner index 188ac07d434..9d1f94121d8 100644 --- a/gcc/ChangeLog.meissner +++ b/gcc/ChangeLog.meissner @@ -1,3 +1,74 @@ +==================== work107, patch #2 ==================== + +Rework 128-bit complex multiply and divide. + +This patch reworks how the complex multiply and divide built-in functions are +done. Previously we created built-in declarations for doing long double complex +multiply and divide when long double is IEEE 128-bit. The old code also did not +support __ibm128 complex multiply and divide if long double is IEEE 128-bit. + +In terms of history, I wrote the original code just as I was starting to test +GCC on systems where IEEE 128-bit long double was the default. At the time, we +had not yet started mangling the built-in function names as a way to bridge +going from a system with 128-bit IBM long double to 128-bin IEEE long double. + +The original code depends on there only being two 128-bit types invovled. With +the next patch in this series, this assumption will no longer be true. When +long double is IEEE 128-bit, there will be 2 IEEE 128-bit types (one for the +explicit __float128/_Float128 type and one for long double). + +The problem is we cannot create two separate built-in functions that resolve to +the same name. This is a requirement of add_builtin_function and the C front +end. That means for the 3 possible modes (IFmode, KFmode, and TFmode), you can +only use 2 of them. + +This code does not create the built-in declaration with the changed name. +Instead, it uses the TARGET_MANGLE_DECL_ASSEMBLER_NAME hook to change the name +before it is written out to the assembler file like it now does for all of the +other long double built-in functions. + +When I wrote these patches, I discovered that __ibm128 complex multiply and +divide had originally not been supported if long double is IEEE 128-bit as it +would generate calls to __mulic3 and __divic3. I added tests in the testsuite +to verify that the correct name (i.e. __multc3 and __divtc3) is used in this +case. + +I had previously sent this patch out on November 1st. Compared to that version, +this version no longer disables the special mapping when you are building +libgcc, as it turns out we don't need it. + +I tested all 3 patchs for PR target/107299 on: + + 1) LE Power10 using --with-cpu=power10 --with-long-double-format=ieee + 2) LE Power10 using --with-cpu=power10 --with-long-double-format=ibm + 3) LE Power9 using --with-cpu=power9 --with-long-double-format=ibm + 4) BE Power8 using --with-cpu=power8 --with-long-double-format=ibm + +Once all 3 patches have been applied, we can once again build GCC when long +double is IEEE 128-bit. There were no other regressions with these patches. +Can I check these patches into the trunk? + +2023-01-20 Michael Meissner <meissner@linux.ibm.com> + +gcc/ + + PR target/107299 + * config/rs6000/rs6000.cc (create_complex_muldiv): Delete. + (init_float128_ieee): Delete code to switch complex multiply and divide + for long double. + (complex_multiply_builtin_code): New helper function. + (complex_divide_builtin_code): Likewise. + (rs6000_mangle_decl_assembler_name): Add support for mangling the name + of complex 128-bit multiply and divide built-in functions. + +gcc/testsuite/ + + PR target/107299 + * gcc.target/powerpc/divic3-1.c: New test. + * gcc.target/powerpc/divic3-2.c: Likewise. + * gcc.target/powerpc/mulic3-1.c: Likewise. + * gcc.target/powerpc/mulic3-2.c: Likewise. + ==================== work107, patch #1 ==================== PR target/107299: Fix build issue when long double is IEEE 128-bit
next reply other threads:[~2023-01-23 21:17 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-23 21:17 Michael Meissner [this message] -- strict thread matches above, loose matches on Subject: below -- 2023-01-25 4:42 Michael Meissner 2023-01-25 3:29 Michael Meissner 2023-01-25 3:00 Michael Meissner 2023-01-23 21:19 Michael Meissner 2023-01-23 21:17 Michael Meissner 2023-01-20 21:02 Michael Meissner 2023-01-20 20:34 Michael Meissner
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