https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71615
Mianzhi Wang <wangmianzhi1 at linuxmail dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID --- Comment #4 from Mianzhi Wang <wangmianzhi1 at linuxmail dot org> --- By executing: $ valgrind --show-emwarns=yes ./test It turned out: ==16833== Emulation warning: unsupported action: ==16833== Setting %mxcsr.fz (SSE flush-underflows-to-zero mode) ==16833== at 0x4006D2: set_fast_math (crtfastmath.c:93) ==16833== by 0x400A8C: __libc_csu_init (in /home/mianzhi/Desktop/test/test) ==16833== by 0x51857BE: (below main) (libc-start.c:247) So it IS an known issue of valgrind. See: ``Valgrind has the following limitations in its implementation of x86/AMD64 SSE2 FP arithmetic, relative to IEEE754'' of: http://valgrind.org/docs/manual/manual-core.html#manual-core.limits Here I'm closing the ticket.