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aarch64: Fix f{max,min}{f} build for GCC 4.9 and 5 

GCC 4.9 and 5 do not generate a correct f{max,min}nm instruction for
__builtin_{fmax,fmin}{f} without -ffinite-math-only.  It is clear a
compiler issue since the instruction can handle NaN and Inf correctly
and GCC6+ does not show this issue.

We can backport a fix to GCC 5, raise the minimum required GCC version
for aarch64 (since GCC 4.9 branch is now closed [1]) and/or add
configure check to check for this issue.  However I think
-ffinite-math-only should be safe for these specific implementations
and it is a simpler solution.

Checked on aarch64-linux-gnu with GCC 5.3.1.

	* sysdeps/aarch64/fpu/Makefile (CFLAGS-s_fmax.c, CFLAGS-s_fmaxf.c,
	CFLAGS-s_fmin.c, CFLAGS-s_fminf.c): New rule: add -ffinite-math-only.

[1] https://gcc.gnu.org/ml/gcc/2016-08/msg00010.html

Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
This commit is contained in:
Adhemerval Zanella 2017-11-16 19:52:59 -02:00
parent 6a6aa1f389
commit 58a813bf6e
2 changed files with 11 additions and 0 deletions
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ChangeLog
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@ -1,3 +1,8 @@
2017-11-16 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* sysdeps/aarch64/fpu/Makefile (CFLAGS-s_fmax.c, CFLAGS-s_fmaxf.c,
CFLAGS-s_fmin.c, CFLAGS-s_fminf.c): New rule: add -ffinite-math-only.
2017-11-16 Joseph Myers <joseph@codesourcery.com>
* sysdeps/unix/sysv/linux/net/if_arp.h (ARPHRD_RAWIP): New macro.

6
sysdeps/aarch64/fpu/Makefile
View File

@ -5,4 +5,10 @@ CFLAGS-s_lroundf.c += -fno-math-errno
CFLAGS-s_lround.c += -fno-math-errno
CFLAGS-s_llroundf.c += -fno-math-errno
CFLAGS-s_llround.c += -fno-math-errno
# GCC 4.9 and 5 requires the flag to correct emits a f{max,min}nm
# for a __builtin_{fmax,fmin}{f}.
CFLAGS-s_fmax.c += -ffinite-math-only
CFLAGS-s_fmaxf.c += -ffinite-math-only
CFLAGS-s_fmin.c += -ffinite-math-only
CFLAGS-s_fminf.c += -ffinite-math-only
endif