RFR: 8290917: x86: Memory-operand arithmetic instructions have too low costs [v6]

[Quan Anh Mai]

> The pattern `AddI (LoadI mem) imm` should be matched by a load followed by an add with constant, instead, it is currently matched as a constant load followed by an add with memory. The reason is that the cost of `addI_rReg_mem` is too low, this patch fixes this by increasing the cost of this fused instruction.
> 
> Testing: Manually run the test case in the JBS and look at the compiled code.
> 
> I also do some small clean-ups in x86_64.ad:
> 
> - The `mulHiL` rules have unnecessary constraints on the input registers, these can be removed. The `no_rax_RegL` operand as a consequence can also be removed.
> - The rules involving long division by a constant can be removed because it has been covered by the optimiser during idealisation.
> - The pattern `SubI src imm` and the likes never match because they are converted to `AddI src -imm` by the optimiser. As a result, these rules can be removed
> - The rules involving shifting the argument by 1 are covered by and exactly the same as the corresponding rules of shifting by an immediate. As a result, they can be removed.
> - Some rules involving and-ing with a bit mask have unnecessary constraints on the target register.
> 
> Please kindly review, thank you very much.

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

  add jmhs

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/9791/files
  - new: https://git.openjdk.org/jdk/pull/9791/files/ef4f3cf9..97d39b7e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9791&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9791&range=04-05

  Stats: 58 lines in 1 file changed: 58 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/9791.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9791/head:pull/9791

PR: https://git.openjdk.org/jdk/pull/9791