Summary:
This patch implements addsf3/__aeabi_fadd in asm for Thumb1.
Compared with generic C version (lib/fp_add_impl.inc), it
1. all constants are materialized instead of loading from constant pool
2. no stack spills (C version uses 136 bytes stack space)
3. clz() is called only when necessary. (C version always calls it)
Reviewers: compnerd, rengolin, asl
Reviewed By: asl
Subscribers: efriedma, aemerson, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D29485
llvm-svn: 294172
Weiming Zhao