GCC8: fails to build when configured --with-cpu=xscale

[Alexey Neyman <stilor at att dot net>]

Hi,

I am seeing the following failure when building a crosstool-NG 
configuration which configures GCC for XScale CPU. The warning is:

cc1: warning: switch -mcpu=xscale conflicts with -march=armv5te switch

But during the build of libatomic, -Werror is thrown in, so the warning 
becomes an error.

GCC is configured with:

CC_FOR_BUILD='x86_64-build_pc-linux-gnu-gcc' CFLAGS='-O2 -g -pipe 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools/include 
' CFLAGS_FOR_BUILD='-O2 -g -pipe 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools/include 
' CXXFLAGS='-O2 -g -pipe 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools/include 
' CXXFLAGS_FOR_BUILD='-O2 -g -pipe 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools/include 
' 
LDFLAGS='-L/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools/lib 
-lstdc++ -lm' CFLAGS_FOR_TARGET='' CXXFLAGS_FOR_TARGET='' 
LDFLAGS_FOR_TARGET='' '/bin/bash' 
'/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/configure' 
'--build=x86_64-build_pc-linux-gnu' '--host=x86_64-build_pc-linux-gnu' 
'--target=armeb-unknown-linux-uclibcgnueabi' 
'--prefix=/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi' 
'--with-sysroot=/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/sysroot' 
'--enable-languages=c,c++' '--with-cpu=xscale' '--with-float=soft' 
'--with-pkgversion=crosstool-NG 1.23.0-392-gd274ab06-dirty' 
'--disable-sjlj-exceptions' '--enable-__cxa_atexit' 
'--disable-libmudflap' '--disable-libgomp' '--disable-libssp' 
'--disable-libquadmath' '--disable-libquadmath-support' 
'--disable-libsanitizer' '--disable-libmpx' 
'--with-gmp=/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools' 
'--with-mpfr=/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools' 
'--with-mpc=/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools' 
'--with-isl=/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/buildtools' 
'--enable-lto' '--with-host-libstdcxx=-static-libgcc 
-Wl,-Bstatic,-lstdc++,-Bdynamic -lm' '--enable-threads=posix' 
'--enable-target-optspace' '--enable-plugin' '--enable-gold' 
'--disable-nls' '--disable-multilib' 
'--with-local-prefix=/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/sysroot' 
'--enable-long-long'

Failing command is:

[ALL  ]    libtool: compile: 
/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/build/build-cc-gcc-final/./gcc/xgcc 
-B/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/build/build-cc-gcc-final/./gcc/ 
-B/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/bin/ 
-B/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/lib/ 
-isystem 
/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/include 
-isystem 
/home/avn/x-tools/armeb-unknown-linux-uclibcgnueabi/armeb-unknown-linux-uclibcgnueabi/sys-include 
-DHAVE_CONFIG_H 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/libatomic/config/arm 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/libatomic/config/linux/arm 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/libatomic/config/posix 
-I/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/libatomic 
-I. -Wall -Werror -pthread -g -O2 -g -Os -MT init.lo -MD -MP -MF 
.deps/init.Tpo -c 
/home/avn/work/ctng/crosstool-ng/.build/armeb-unknown-linux-uclibcgnueabi/src/gcc/libatomic/config/linux/arm/init.c 
-fPIC -DPIC -o .libs/init.o

The problem, as far as I can see, is that the driver executes cc1 with 
the flags defined in

#define OPTION_DEFAULT_SPECS \
  {"arch", "%{!march=*:%{!mcpu=*:-march=%(VALUE)}}" }, \
  {"cpu", "%{!march=*:%{!mcpu=*:-mcpu=%(VALUE)}}" }, \
  {"tune", "%{!mcpu=*:%{!mtune=*:-mtune=%(VALUE)}}" }, \
  {"float", "%{!mfloat-abi=*:-mfloat-abi=%(VALUE)}" }, \
  {"fpu", "%{!mfpu=*:-mfpu=%(VALUE)}"}, \
  {"abi", "%{!mabi=*:-mabi=%(VALUE)}"}, \
  {"mode", "%{!marm:%{!mthumb:-m%(VALUE)}}"}, \
  {"tls", "%{!mtls-dialect=*:-mtls-dialect=%(VALUE)}"},

Which evaluates to:

-mcpu=xscale -mfloat-abi=soft -mtls-dialect=gnu -marm -march=armv5te

added to the arguments from the command line (as you may see, there were 
no -march= or -mcpu= in the original command).

Then, cc1 discovers that -mcpu=xscale and -march=armv5te are not exactly 
compatible:

(gdb) p arm_selected_cpu->common.isa_bits
$17 = {isa_bit_armv3m, isa_bit_mode32, isa_bit_notm, isa_bit_xscale, 
isa_bit_armv4, isa_bit_armv5e, isa_bit_armv5, isa_bit_thumb, isa_nobit 
<repeats 36 times>}
(gdb) p arm_selected_arch->common.isa_bits
$18 = {isa_bit_armv3m, isa_bit_mode32, isa_bit_notm, isa_bit_armv4, 
isa_bit_armv5e, isa_bit_armv5, isa_bit_thumb, isa_nobit <repeats 37 times>}

Because they differ in the presence of isa_bit_xscale (and that bit is 
not listed as a quirk that's ignored during comparison), cc1 complains.

What should be the fix for this?

Regards,
Alexey.