[Bug target/20540] New: "-march=i386" doesn't mean "limit instruction set to what 80386 understands"
gcc version 3.4.3-20050110 (Gentoo Linux 3.4.3.20050110, ssp-3.4.3.20050110-0,
pie-8.7.7)
Basically, I get P6 instructions in the assembly output when compiling with
"-march=i386", but when I tried "-march=i486" id did the right thing (no P6
instructions).
I hope it is just a simple problem of misunderstanding "i386" to mean something
other than what the documentation (read: man page) says, rather than an actual
bug with the definition of what instructions 386 can and can't issue.
I don't think it's Gentoo's fault so I complain here.
--
Summary: "-march=i386" doesn't mean "limit instruction set to
what 80386 understands"
Product: gcc
Version: 3.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: target
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: zeev dot tarantov at gmail dot com
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20540
[Bug target/20540] "-march=i386" doesn't mean "limit instruction set to what 80386 understands"
--- Additional Comments From zeev dot tarantov at gmail dot com 2005-03-18 20:26 --- Created an attachment (id=8418) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8418&action=view) testcase source -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20540
[Bug target/20540] "-march=i386" doesn't mean "limit instruction set to what 80386 understands"
--- Additional Comments From zeev dot tarantov at gmail dot com 2005-03-18 20:27 --- Created an attachment (id=8419) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8419&action=view) testcase expected output this is what I get from "gcc -march=i486 -O3 -S -g opcode.c -o opcode.i486.s" -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20540
[Bug target/20540] "-march=i386" doesn't mean "limit instruction set to what 80386 understands"
--- Additional Comments From zeev dot tarantov at gmail dot com 2005-03-18 20:36 --- Created an attachment (id=8420) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8420&action=view) testcase unexpected output this is what I get from "gcc -march=i386 -O3 -S -g opcode.c -o opcode.i386.s". Notice the "movzbl" on line 28. I don't have a 80386 to test it, but I doubt it supports this. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20540
[Bug target/20540] "-march=i386" doesn't mean "limit instruction set to what 80386 understands"
--- Additional Comments From zeev dot tarantov at gmail dot com 2005-03-18 20:47 --- I forgot to say gcc was compiled with "-march=pentium3 -O3". I tried it now on gcc 3.3.5 and got the same deal. -- What|Removed |Added GCC host triplet||i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20540
[Bug inline-asm/37492] New: optimization causes inline assembler to emit syntax errors
Compiling the following with -O0 works. Compiling with -O2 produces assembly
syntax errors.
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-4.3.1-r1/work/gcc-4.3.1/configure --prefix=/usr
--bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.3.1
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.3.1/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.3.1/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.3.1/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --enable-secureplt --disable-multilib --enable-libmudflap
--disable-libssp --enable-cld --enable-java-awt=gtk --with-arch=i686
--enable-languages=c,c++,java,treelang --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.3.1-r1 p1.1'
Thread model: posix
gcc version 4.3.1 (Gentoo 4.3.1-r1 p1.1)
#include
void test(unsigned int val)
{
unsigned int res, resz;
asm(
" xorl %1, %1\n"
" movl $0x12345678, %0\n"
" bsrl %2, %0 ; setz %b1 "
: "=r" (res), "=r" (resz)
: "g" (val)
);
printf("val : %d\n", val);
printf("res : %d\n", res);
printf("resz: %d\n", resz);
}
int main()
{
test(0);
test(1 << 7);
test(1 << 15);
test(1 << 30);
return 0;
}
--
Summary: optimization causes inline assembler to emit syntax
errors
Product: gcc
Version: 4.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: inline-asm
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: zeev dot tarantov at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37492
[Bug inline-asm/37492] optimization causes inline assembler to emit syntax errors
--- Comment #2 from zeev dot tarantov at gmail dot com 2008-09-12 14:24 --- Thank you so much and sorry for the spam in bugzilla. Is there anything like lint that would have helped me understand the mistake, without actually grokking the documentation? -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37492
