From 58a813bf6e732211af53e690c92c14a50bb06e0e Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Thu, 16 Nov 2017 19:52:59 -0200 Subject: [PATCH] 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 Reviewed-by: Szabolcs Nagy --- ChangeLog | 5 +++++ sysdeps/aarch64/fpu/Makefile | 6 ++++++ 2 files changed, 11 insertions(+) diff --git a/ChangeLog b/ChangeLog index 0d5998f67c..81b71a5a0e 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2017-11-16 Adhemerval Zanella + + * 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 * sysdeps/unix/sysv/linux/net/if_arp.h (ARPHRD_RAWIP): New macro. diff --git a/sysdeps/aarch64/fpu/Makefile b/sysdeps/aarch64/fpu/Makefile index bf38f2c589..4a182bd6d6 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