https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63228
Bug ID: 63228
Summary: -m16 doesn't work if gcc is compiled for x32
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: mikulas at artax dot karlin.mff.cuni.cz
Host: x86_64-linux-gnux32
Target: x86_64-linux-gnux32
Build: x86_64-linux-gnux32
When gcc is configured and compiled for x32 mode (x86_64-linux-gnux32 triplet),
the flag -m16 doesn't work. The bug was reproduced on gcc-4.9.1-13 from Debian
Ports x32 distribution (https://wiki.debian.org/X32Port)
Attempting to compile or assemble anything with "gcc -m16 -march=i386" results
in this error message:
error: CPU you selected does not support x86-64 instruction set
(this error causes linux kernel 3.16.2 compilation failure)
If you remove "-march=i386", the file is compiled, but it can't be assembled,
because gcc generates incorrect assembler as if it was x86_64 target. For
example, compiling a file test.c containing "int bla(void) { return 3; }" with
"gcc -c -m16 test.c", results in these error messages:
/tmp/cc89iTZG.s: Assembler messages:
/tmp/cc89iTZG.s:9: Error: bad register name `%rbp'
/tmp/cc89iTZG.s:15: Error: bad register name `%rbp'
When gcc is configured for x86_64 mode (x86_64-unknown-linux-gnu), -m16 works
correctly.
