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e93c264336
glibc/sysdeps/ieee754
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Vineet Gupta e93c264336 ieee754/dbl-64: Reduce the scope of temporary storage variables 
This came to light when adding hard-flaot support to ARC glibc port
without hardware sqrt support causing glibc build to fail:

| ../sysdeps/ieee754/dbl-64/e_sqrt.c: In function '__ieee754_sqrt':
| ../sysdeps/ieee754/dbl-64/e_sqrt.c:58:54: error: unused variable 'ty' [-Werror=unused-variable]
|   double y, t, del, res, res1, hy, z, zz, p, hx, tx, ty, s;

The reason being EMULV() macro uses the hardware provided
__builtin_fma() variant, leaving temporary variables 'p, hx, tx, hy, ty'
unused hence compiler warning and ensuing error.

The intent of the patch was to fix that error, but EMULV is pervasive
and used fair bit indirectly via othe rmacros, hence this patch.
Functionally it should not result in code gen changes and if at all
those would be better since the scope of those temporaries is greatly
reduced now

Built tested with aarch64-linux-gnu arm-linux-gnueabi arm-linux-gnueabihf hppa-linux-gnu x86_64-linux-gnu arm-linux-gnueabihf riscv64-linux-gnu-rv64imac-lp64 riscv64-linux-gnu-rv64imafdc-lp64 powerpc-linux-gnu microblaze-linux-gnu nios2-linux-gnu hppa-linux-gnu

Also as suggested by Joseph [1] used --strip and compared the libs with
and w/o patch and they are byte-for-byte unchanged (with gcc 9).

| for i in `find . -name libm-2.31.9000.so`;
| do
|    echo $i; diff $i /SCRATCH/vgupta/gnu2/install/glibcs/$i ; echo $?;
| done

| ./aarch64-linux-gnu/lib64/libm-2.31.9000.so
| 0
| ./arm-linux-gnueabi/lib/libm-2.31.9000.so
| 0
| ./x86_64-linux-gnu/lib64/libm-2.31.9000.so
| 0
| ./arm-linux-gnueabihf/lib/libm-2.31.9000.so
| 0
| ./riscv64-linux-gnu-rv64imac-lp64/lib64/lp64/libm-2.31.9000.so
| 0
| ./riscv64-linux-gnu-rv64imafdc-lp64/lib64/lp64/libm-2.31.9000.so
| 0
| ./powerpc-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./microblaze-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./nios2-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./hppa-linux-gnu/lib/libm-2.31.9000.so
| 0
| ./s390x-linux-gnu/lib64/libm-2.31.9000.so

[1] https://sourceware.org/pipermail/libc-alpha/2019-November/108267.html
2020-06-15 13:09:21 -07:00
..
dbl-64 ieee754/dbl-64: Reduce the scope of temporary storage variables 2020-06-15 13:09:21 -07:00
float128 ieee754: provide gcc builtins based generic fma functions 2020-06-03 10:23:28 -07:00
flt-32 ieee754: provide gcc builtins based generic sqrt functions 2020-06-03 10:23:22 -07:00
ldbl-64-128
ldbl-96 Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
ldbl-128 ieee754: provide gcc builtins based generic fma functions 2020-06-03 10:23:28 -07:00
ldbl-128ibm Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
ldbl-128ibm-compat powerpc64le: blacklist broken GCC compilers (e.g GCC 7.5.0) 2020-04-30 08:52:08 -05:00
ldbl-opt Rename __LONG_DOUBLE_USES_FLOAT128 to __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI 2020-04-30 08:52:08 -05:00
soft-fp Update copyright dates with scripts/update-copyrights. 2020-01-01 00:14:33 +00:00
ieee754.h Update copyright dates with scripts/update-copyrights. 2020-01-01 00:14:33 +00:00
k_standard.c Use copysign functions not __copysign functions in glibc libm. 2018-09-27 20:04:48 +00:00
k_standardf.c Update copyright dates with scripts/update-copyrights. 2020-01-01 00:14:33 +00:00
k_standardl.c Update copyright dates with scripts/update-copyrights. 2020-01-01 00:14:33 +00:00
libm-alias-finite.h Add libm_alias_finite for _finite symbols 2020-01-03 10:02:04 -03:00
Makefile Avoid -Wno-write-strings for k_standard.c. 2015-02-26 22:50:54 +00:00
s_lib_version.c Simplify math-svid-compat code. 2017-08-28 15:19:52 +00:00
s_matherr.c Obsolete matherr, _LIB_VERSION, libieee.a. 2017-08-21 17:45:10 +00:00
s_signgam.c Remove unnecessary math_private.h includes. 2018-09-28 21:53:33 +00:00