I've built a half-dozen GCC 4.0.0 based compilers in parallel (make -j2) on Linux without a hitch. But I received the following error building an sh-elf toolchain. make is deciding to rebuild cc1 after cross building much of libgcc already, and then, when it tries to use this new cc1 (perhaps before it is fully written?)...
/usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/gcc/xgcc -B/usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/gcc/ -nostdinc -B/usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/sh-elf/newlib/ -isystem /usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/sh-elf/newlib/targ-include -isystem /usr/src/redhat/BUILD/gcc-4.0.0/newlib/libc/include -B/usr/sh-elf/bin/ -B/usr/sh-elf/lib/ -isystem /usr/sh-elf/include -isystem /usr/sh-elf/sys-include -O2 -DIN_GCC -DCROSS_COMPILE -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem ./include -g -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -Dinhibit_libc -I. -I. -I../../gcc -I../../gcc/. -I../../gcc/../include -I../../gcc/../libcpp/include -DL_ashrdi3 -c ../../gcc/libgcc2.c -o libgcc/./_ashrdi3.o gcc -g -O2 -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wno-variadic-macros -Wold-style-definition -DIN_GCC -DCROSS_COMPILE -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -pedantic -Wno-long-long -Wno-variadic-macros -Wold-style-definition -DHAVE_CONFIG_H -o cc1 \ c-parse.o c-lang.o stub-objc.o attribs.o c-errors.o c-lex.o c-pragma.o c-decl.o c-typeck.o c-convert.o c-aux-info.o c-common.o c-opts.o c-format.o c-semantics.o c-incpath.o cppdefault.o c-ppoutput.o c-cppbuiltin.o prefix.o c-objc-common.o c-dump.o c-pch.o c-gimplify.o tree-mudflap.o c-pretty-print.o main.o libbackend.a ../libcpp/libcpp.a ../libcpp/libcpp.a ../libiberty/libiberty.a /usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/gcc/xgcc -B/usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/gcc/ -nostdinc -B/usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/sh-elf/newlib/ -isystem /usr/src/redhat/BUILD/gcc-4.0.0/obj-sh-elf/sh-elf/newlib/targ-include -isystem /usr/src/redhat/BUILD/gcc-4.0.0/newlib/libc/include -B/usr/sh-elf/bin/ -B/usr/sh-elf/lib/ -isystem /usr/sh-elf/include -isystem /usr/sh-elf/sys-include -O2 -DIN_GCC -DCROSS_COMPILE -W -Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem ./include -g -DIN_LIBGCC2 -D__GCC_FLOAT_NOT_NEEDED -Dinhibit_libc -I. -I. -I../../gcc -I../../gcc/. -I../../gcc/../include -I../../gcc/../libcpp/include -DL_cmpdi2 -c ../../gcc/libgcc2.c -o libgcc/./_cmpdi2.o xgcc: installation problem, cannot exec 'cc1': No such file or directory make[2]: *** [libgcc/./_cmpdi2.o] Error 1 Rerunning make gets it going again. I'll attach more of the relevant log file to this issue. -- Summary: Spontaneous cc1 rebuild during parallel make causes build failure. Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: bootstrap AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: green at redhat dot com CC: gcc-bugs at gcc dot gnu dot org GCC host triplet: i686-pc-linux-gnu GCC target triplet: sh-elf http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21216