https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85922
Bug ID: 85922 Summary: bootstrapping fails with -O3 because gcc 8.1.0 generates unknown instruction pshufb Product: gcc Version: 8.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: bootstrap Assignee: unassigned at gcc dot gnu.org Reporter: gcc at mailinator dot com Target Milestone: --- On bootstrapping after implementing an hack for #85921 (environment and options used specified there) bootstrapping failed: Command issued by make: /some/userdir/gcc-8.1.0-build/libiberty> /some/userdir/gcc-8.1.0-build/./prev-gcc/xgcc -B/some/userdir/gcc-8.1.0-build/./prev-gcc/ -B/some/userdir/i686-pc-linux-gnu/bin/ -B/some/userdir/i686-pc-linux-gnu/bin/ -B/some/userdir/i686-pc-linux-gnu/lib/ -isystem /some/userdir/i686-pc-linux-gnu/include -isystem /some/userdir/i686-pc-linux-gnu/sys-include -c -DHAVE_CONFIG_H -O3 -march=native -gtoggle -I. -I../../gcc-8.1.0/libiberty/../include -W -Wall -Wwrite-strings -Wc++-compat -Wstrict-prototypes -Wshadow=local -pedantic -D_GNU_SOURCE ../../gcc-8.1.0/libiberty/sha1.c -o sha1.o error message: /tmp/ccuTEPxe.s: Assembler messages: /tmp/ccuTEPxe.s:3277: Error: no such instruction: `pshufb .LC2,%xmm0' The same instruction is generated for a lot of other sources, too (as shown by `make -k BOOT_CFLAGS='-O3 -march=native' CPATH="/some/userdir/include" bootstrap-lean` Workaround: compile with -O2 (the default)