[Bug c/84284] New: ICE compiling printf("\n"); with -fexec-charset=UTF-16

["helge.hafting at ntnu dot no" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84284

            Bug ID: 84284
           Summary: ICE compiling printf("\n"); with -fexec-charset=UTF-16
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helge.hafting at ntnu dot no
  Target Milestone: ---

Created attachment 43370
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=43370&action=edit
bug.cpp and bug.ii, the minimal file causing the ICE. (.cpp and .ii are
identical)

I am not sure that the testcase should compile with that flag, but even an
error message ought to be better than 'internal compiler error'.

I use either of these command lines:
gcc  -fexec-charset=UTF-16 bug.cpp
g++  -fexec-charset=UTF-16 bug.cpp

to compile this bug.cpp:

extern "C" int printf(const char *, ...);
void ice() {
 printf("\n");
}

And get:
bug.cpp: In function ‘void ice()’:
bug.cpp:3:15: internal compiler error: character 0xa is not unibyte in
execution character set
         printf("\n");
         ~~~~~~^~~~~~
Please submit a full bug report,

bug.cpp and bug.ii is attached. Other information you request:
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/7.2.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 7.2.1 20180116 (GCC) 

g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/7.2.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --enable-multilib --disable-werror
--enable-checking=release --enable-default-pie --enable-default-ssp
Thread model: posix
gcc version 7.2.1 20180116 (GCC)