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From: Michael Meissner <meissner@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/meissner/heads/work106)] Update ChangeLog.meissner Date: Fri, 13 Jan 2023 00:03:53 +0000 (GMT) [thread overview] Message-ID: <20230113000353.48B0C3858C66@sourceware.org> (raw) https://gcc.gnu.org/g:9b3eddb60a24f54fd23f4564ef466c635cee2e1a commit 9b3eddb60a24f54fd23f4564ef466c635cee2e1a Author: Michael Meissner <meissner@linux.ibm.com> Date: Thu Jan 12 19:03:49 2023 -0500 Update ChangeLog.meissner Diff: --- gcc/ChangeLog.meissner | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) diff --git a/gcc/ChangeLog.meissner b/gcc/ChangeLog.meissner index c9a386d7b51..7bdf0a234ad 100644 --- a/gcc/ChangeLog.meissner +++ b/gcc/ChangeLog.meissner @@ -1,3 +1,63 @@ +==================== work106, patch #1 ==================== + +PR target/107299: Update IEEE 128-bit types for PowerPC libgcc + +This patch updates the IEEE 128-bit types in libgcc. + +At the moment, we cannot build GCC when the target uses IEEE 128-bit long +doubles, such as building the compiler for a native Fedora 36 system. The +build dies when it is trying to build the _mulkc3.c and _divkc3 modules. + +This patch changes the IEEE 128-bit type (TFtype) in the IEEE 128-bit support +to use either _Float128 or long double. Previously we would use the __float128 +type. In addition, the TCtype will use the same type along with _Complex. + +I changed the libgcc build so that the IEEE 128-bit support is now compiled +with -mabi=ieeelongdouble. For the _mulkc3 and _divkc3, I explicitly use long +double and long double _Complex to avoid type mismatch errors. + +While it is desirable to ultimately have __float128 and _Float128 use the same +internal type and mode within GCC, at present if you use the option +-mabi=ieeelongdouble, the __float128 type will use the long double type. We +get an internal compiler error if we combine the signbitf128 built-in with a +long double type. + +I've gone through several iterations of trying to fix this within GCC, and +there are various problems that have come up. I developed this alternative +patch that changes libgcc so that it does not tickle the issue. I hope we can +fix the compiler at some point, but right now, this is preventing people on +Fedora 36 systems from building compilers where the default long double is IEEE +128-bit. + +2023-01-12 Michael Meissner <meissner@linux.ibm.com> + + PR target/107299 + * config/rs6000/_divkc3.c (toplevel): Add assertion for building with + -mabi=ieeelongdouble. Remove code supporting -mabi=ibmlongdouble. + (COPYSIGN): Use the long double built-in. + (INFINITY): Likewise. + (FABS): Likewise. + * config/rs6000/_mulkc3.c (toplevel): Add assertion for building with + -mabi=ieeelongdouble. + (COPYSIGN): Use the long double built-in. + (INFINITY): Likewise. + * config/rs6000/float128-ifunc.c (toplevel): Add assertion for building + with -mabi=ieeelongdouble. + * config/rs6000/quad-float128.h (TF): Delete definition. + (TFtype): Define to be _Float128 or long double. + (TCtype): Define to be _Complex _Float128 or _Complex long double. + (__mulkc3_sw): Only declare function if -mabi=ieeelongdouble. + (__divkc3_sw): Likewise. + (__mulkc3_hw): Likewise. + (__divkc3_hw): Likewise. + (__mulkc3): Likewise. + (__divkc3): Likewise. + * config/rs6000/t-float128 (FP128_CFLAGS_SW): Add -mabi=ieeelongdouble. + * config/rs6000/t-float128-hw (FP128_CFLAGS_HW): Likewise. + * libgcc2.h (TFtype): Allow MD code to override definition. + (TCtype): Likewise. + * soft-fp/quad.h (TFtype): Likewise. + 2023-01-12 Michael Meissner <meissner@linux.ibm.com> Clone branch
next reply other threads:[~2023-01-13 0:03 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-01-13 0:03 Michael Meissner [this message] 2023-01-18 0:12 Michael Meissner 2023-01-18 2:39 Michael Meissner 2023-01-18 6:12 Michael Meissner 2023-01-18 8:57 Michael Meissner 2023-01-18 16:20 Michael Meissner
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