Created attachment 32776 [details]
compressed build log

Building an SH cross GCC on OSX with clang results in the following errors:

../../gcc-trunk/gcc/wide-int.cc:1269:23: error: invalid use of a cast in a inline asm context requiring an l-value: remove the cast or build with -fheinous-gnu-extensions
          umul_ppmm (val[1], val[0], op1.ulow (), op2.ulow ());
          ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gcc-trunk/gcc/../include/longlong.h:505:24: note: expanded from macro 'umul_ppmm'
           : "=a" ((UDItype) (w0)),                                     \
                              ^
../../gcc-trunk/gcc/wide-int.cc:1269:15: error: invalid use of a cast in a inline asm context requiring an l-value: remove the cast or build with -fheinous-gnu-extensions
          umul_ppmm (val[1], val[0], op1.ulow (), op2.ulow ());
          ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gcc-trunk/gcc/../include/longlong.h:506:24: note: expanded from macro 'umul_ppmm'
             "=d" ((UDItype) (w1))                                      \
                              ^
../../gcc-trunk/gcc/wide-int.cc:1278:22: error: invalid use of a cast in a inline asm context requiring an l-value: remove the cast or build with -fheinous-gnu-extensions
          umul_ppmm (upper, val[0], op1.ulow (), op2.ulow ());
          ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gcc-trunk/gcc/../include/longlong.h:505:24: note: expanded from macro 'umul_ppmm'
           : "=a" ((UDItype) (w0)),                                     \
                              ^
../../gcc-trunk/gcc/wide-int.cc:1278:15: error: invalid use of a cast in a inline asm context requiring an l-value: remove the cast or build with -fheinous-gnu-extensions
          umul_ppmm (upper, val[0], op1.ulow (), op2.ulow ());
          ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../gcc-trunk/gcc/../include/longlong.h:506:24: note: expanded from macro 'umul_ppmm'
             "=d" ((UDItype) (w1))

The full log is attached, which shows also other (spurious) warnings.

The problem can be worked around by setting
export CFLAGS="-fheinous-gnu-extensions"
export CXXFLAGS="-fheinous-gnu-extensions"
export CFLAGS_FOR_TARGET="-O2"
export CXXFLAGS_FOR_TARGET="-O2"

The *FLAGS_FOR_TARGET are required or else they will be set to *FLAGS, which will pass -fheinous-gnu-extensions to the SH xgcc when building libgcc etc. (PR 25672)

The clang version on my OSX system:
clang -v
Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
Target: x86_64-apple-darwin13.1.0
Thread model: posix