[Bug target/77599] M68K: __builtin_bswap32() isn't compiled correctly with -mshort
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77599
Jeffrey A. Law changed:
What|Removed |Added
Status|UNCONFIRMED |RESOLVED
CC||law at redhat dot com
Resolution|--- |INVALID
--- Comment #2 from Jeffrey A. Law ---
The problem here is you're using -mshort on *-linux-gnu which IMHO is invalid.
Linux defines int32_t as a "int". And -mshort changes the width of an int to
16 bits, at which point anything prototyped using int32_t has just changed its
ABI in a meaningful way (similarly for uint32_t, but unsigned). You can see
this in the .optimized dump file:
x (long unsigned int y)
{
unsigned int _1;
unsigned int _2;
long unsigned int _4;
;; basic block 2, loop depth 0, count 0, freq 1, maybe hot
;;prev block 0, next block 1, flags: (NEW, REACHABLE, VISITED)
;;pred: ENTRY [100.0%] (FALLTHRU,EXECUTABLE)
_1 = (unsigned int) y_3(D);
_2 = __builtin_bswap32 (_1);
_4 = (long unsigned int) _2;
return _4;
}
Note the type of the _1 and _2. They are both unsigned ints, so 16 bits.
If you try this test on a bare metal target such as m68k-elf or without the
-mshort, you'll get the expected and desired result.
[Bug target/77599] M68K: __builtin_bswap32() isn't compiled correctly with -mshort
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77599 --- Comment #1 from dhowells at redhat dot com --- warthog>m68k-linux-gnu-gcc -v Using built-in specs. COLLECT_GCC=/usr/bin/m68k-linux-gnu-gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/m68k-linux-gnu/6.1.1/lto-wrapper Target: m68k-linux-gnu Configured with: ../gcc-6.1.1-20160427/configure --bindir=/usr/bin --build=x86_64-redhat-linux-gnu --datadir=/usr/share --disable-decimal-float --disable-dependency-tracking --disable-gold --disable-libgcj --disable-libgomp --disable-libmpx --disable-libquadmath --disable-libssp --disable-libunwind-exceptions --disable-shared --disable-silent-rules --disable-sjlj-exceptions --disable-threads --with-ld=/usr/bin/m68k-linux-gnu-ld --enable-__cxa_atexit --enable-checking=release --enable-gnu-unique-object --enable-initfini-array --enable-languages=c,c++ --enable-linker-build-id --enable-lto --enable-nls --enable-obsolete --enable-plugin --enable-targets=all --exec-prefix=/usr --host=x86_64-redhat-linux-gnu --includedir=/usr/include --infodir=/usr/share/info --libexecdir=/usr/libexec --localstatedir=/var --mandir=/usr/share/man --prefix=/usr --program-prefix=m68k-linux-gnu- --sbindir=/usr/sbin --sharedstatedir=/var/lib --sysconfdir=/etc --target=m68k-linux-gnu --with-bugurl=http://bugzilla.redhat.com/bugzilla/ --with-isl --with-newlib --with-plugin-ld=/usr/bin/m68k-linux-gnu-ld --with-sysroot=/usr/m68k-linux-gnu/sys-root --with-system-libunwind --with-system-zlib --without-headers --with-linker-hash-style=gnu Thread model: single gcc version 6.1.1 20160427 (Red Hat Cross 6.1.1-1) (GCC)
