[Bug target/21255] %R and %S are not safe to use from asms

["helloqirun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=21255

Qirun Zhang <helloqirun at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |helloqirun at gmail dot com

--- Comment #9 from Qirun Zhang <helloqirun at gmail dot com> ---
This regression crashes the current trunk.


$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 6.0.0 20160211 (experimental) [trunk revision 233345] (GCC) 



$ gcc-trunk pr21255-3.c 
pr21255-3.c: In function âfâ:
pr21255-3.c:13:1: internal compiler error: in ix86_print_operand, at
config/i386/i386.c:17094
 }
 ^
0xea8432 ix86_print_operand(_IO_FILE*, rtx_def*, int)
        ../../gcc/gcc/config/i386/i386.c:17094
0x86830c output_operand(rtx_def*, int)
        ../../gcc/gcc/final.c:3843
0x868db7 output_asm_insn(char const*, rtx_def**)
        ../../gcc/gcc/final.c:3740
0x86aa03 final_scan_insn(rtx_insn*, _IO_FILE*, int, int, int*)
        ../../gcc/gcc/final.c:2624
0x86b012 final(rtx_insn*, _IO_FILE*, int)
        ../../gcc/gcc/final.c:2045
0x86b7c9 rest_of_handle_final
        ../../gcc/gcc/final.c:4441
0x86b7c9 execute
        ../../gcc/gcc/final.c:4516
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