cmd/compile: add rewrite rules for arithmetic operations

[y1yang0]

What version of Go are you using (go version)?

$ go version

Does this issue reproduce with the latest release?

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

What did you do?

Hi, I found that we have a potential local optimization for subtraction involving common integers, which is also implemented in other compilers. i.e. (t + x) - (t + y) ==> x - y. The compiler itself matches such a pattern 303 times after a quick try, it seems that this could be a candidate for generic rules. I'd like to add it if you think it's worth doing. Thanks for your patience.

What did you expect to see?

What did you see instead?

[randall77]

Sure.

[gopherbot]

Change https://go.dev/cl/477555 mentions this issue: cmd/compile: add rewrite rules for arithmetic operations