Summary:
Previously the method would simply return false, causing every single
inline assembly constraint to trigger a compile error.
This adds inline assembly constraint support for the AVR target.
This patch is derived from the code in
AVRISelLowering::getConstraintType.
More details can be found on the AVR-GCC reference wiki
http://www.nongnu.org/avr-libc/user-manual/inline_asm.html
Reviewers: jroelofs, asl
Reviewed By: asl
Subscribers: asl, ahatanak, saaadhu, cfe-commits
Differential Revision: https://reviews.llvm.org/D28344
llvm-svn: 294176