RFR: 8282204: Use lea instructions for arithmetic operations on x86_64 [v6]

[Quan Anh Mai]

> Hi,
> 
> This patch adds several matching rules for x86_64 backend to use `lea` instructions for several fused arithmetic operations. Also, `lea`s don't kill flags and allow different `dst` and `src`, so it is preferred over `sll` if possible, too. 
> 
> Thank you very much.

Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:

  reviews

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7560/files
  - new: https://git.openjdk.java.net/jdk/pull/7560/files/41fd4801..a866de71

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7560&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7560&range=04-05

  Stats: 6 lines in 2 files changed: 4 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7560.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7560/head:pull/7560

PR: https://git.openjdk.java.net/jdk/pull/7560