| Message ID | 1510914762-27547-1-git-send-email-adhemerval.zanella@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | aarch64: Fix f{max,min}{f} build for GCC 4.9 and 5 | expand |
On 17/11/17 10:32, Adhemerval Zanella wrote: > 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 backport a fix to GCC 5, raise the minimum required GCC version > for aarch64 (since GCC 4.9 branch is now closed) and/or add configure > check to check for this issue. However I think -ffinit-math-only > should be safe for these specific implementation and it is a much > 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. > OK.
diff --git a/sysdeps/aarch64/fpu/Makefile b/sysdeps/aarch64/fpu/Makefile index bf38f2c..4a182bd 100644 --- a/sysdeps/aarch64/fpu/Makefile +++ b/sysdeps/aarch64/fpu/Makefile @@ -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
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 backport a fix to GCC 5, raise the minimum required GCC version for aarch64 (since GCC 4.9 branch is now closed) and/or add configure check to check for this issue. However I think -ffinit-math-only should be safe for these specific implementation and it is a much 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> --- ChangeLog | 5 +++++ sysdeps/aarch64/fpu/Makefile | 6 ++++++ 2 files changed, 11 insertions(+) -- 2.7.4