Package: gcc-5 Version: 5.3.1-3 Severity: normal I couldn't find anything on the matter, but what happens if -march is repeated more than once? I would assume the usual behavior that the last flag "wins".
On a haswell host, the following: gcc -march=native -march=opteron or gcc -march=opteron -march=native both emit code which is illegal for the opteron ISA, as if -march=native had special treatment. Specifying -march=opteron alone works as intended. Since I generally override the default flags in makefiles by appending exceptions where needed, I'd sort of expected the regular behavior. Is this intended? Thanks. -- System Information: Debian Release: stretch/sid APT prefers unstable APT policy: (900, 'unstable'), (800, 'experimental') Architecture: amd64 (x86_64) Kernel: Linux 4.3.0-1-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages gcc-5 depends on: ii binutils 2.25.90.20151209-1 ii cpp-5 5.3.1-3 ii gcc-5-base 5.3.1-3 ii libc6 2.21-4 ii libcc1-0 5.3.1-3 ii libgcc-5-dev 5.3.1-3 ii libgcc1 1:5.3.1-3 ii libgmp10 2:6.1.0+dfsg-2 ii libisl15 0.15-3 ii libmpc3 1.0.3-1 ii libmpfr4 3.1.3-2 ii libstdc++6 5.3.1-3 ii zlib1g 1:1.2.8.dfsg-2+b1 Versions of packages gcc-5 recommends: ii libc6-dev 2.21-4 Versions of packages gcc-5 suggests: ii gcc-5-doc 5.2.0-1 pn gcc-5-locales <none> pn gcc-5-multilib <none> pn libasan2-dbg <none> pn libatomic1-dbg <none> pn libcilkrts5-dbg <none> pn libgcc1-dbg <none> pn libgomp1-dbg <none> pn libitm1-dbg <none> pn liblsan0-dbg <none> pn libmpx0-dbg <none> pn libquadmath0-dbg <none> pn libtsan0-dbg <none> pn libubsan0-dbg <none>