[PATCH] [AArch64] Combine multiple FDIVs with the same divisor

[Chad Rosier]

For reference, Ben proposed a target-independent solution here:
http://llvm.org/bugs/show_bug.cgi?id=16218

Unfortunately, it never made it into mainline because there were some regressions that needed inspection.  The obvious advantage of the target-independent approach is that it works for all targets and across basic blocks.  However, performing this transform across basic blocks may not matter in practice, as Duncan pointed out.  Also, it may prevent other IR transforms from firing.

http://reviews.llvm.org/D6334