[PATCH] [AArch64] Lower SHL_PARTS, SRA_PARTS and SRL_PARTS

[Tim Northover]

  Hi GuanHong,

  Sorry it took so long to review this. The code itself looks fine, but could you make the tests a bit more convincing by tracking which registers are actually used? E.g. "movz [[SIXTYFOUR:x[0-9]+]], #64; sub [[EXTRASHIFT:x[0-9]+]], [[SIXTYFOUR]], w1; ..."

  Cheers.

  Tim.

http://llvm-reviews.chandlerc.com/D3076