[Bug rtl-optimization/59086] [4.9 Regression] error: ‘asm’ operand has impossible constraints

[aivchenk at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59086

--- Comment #7 from Alexander Ivchenko <aivchenk at gmail dot com> ---
Do we have any documentation that states how many registers can be used in
inline assembler for a particular arch and optset? "almost all" is not good
enough for that.

If the user code that worked in 4.8 correctly is now broken for 4.9, we better
need to respect the user and document it properly.