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

[Hao Liu]

>>! In D6334#5, @mcrosier wrote:
> 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.

Hi Chad,

Yes, if it cross basic blocks, sometimes it may cause regressions. Also, as it is a target specific problem, so we think it's better to do such combine in CodeGen.

Thanks,
-Hao

http://reviews.llvm.org/D6334