Hi everyone,

I've been looking at some node-level optimisations as of late, and I came across a couple of potential ones while doing experiments with the test on i38527, namely (R is an ordinal tempref, and n is an ordinal constant):

add
  |- add
  |   |- R
  |   |- R
  |
  |- R

Becoming:

mul
  |- R
  |- 3

And:

add
  |- mul
  |   |- R
  |   |- n
  |
  |- R

Becoming:

mul
  |- R
  |- n+1

I've been having a couple of issues though that I haven't been able to solve, the main thing is that taddnode.simplify doesn't get called to transmute the nodes as desired because pass 1 is already complete for most of the nodes by the time CSE is executed.

I've tried a few workarounds, but ran into problems:

- Once CSE is complete, calling simplify via foreachnodestatic with the pre-process option is unacceptably slow.
- Attempting to selectively reset the pass 1 flags (in an attempt to minimise the massive performance loss with manually calling simplify as above) causes Internal Error 200405231 because it seems to upset implicit finally blocks.
- Moving "add_entry_exit_code" to after "optcse" causes compilation of case blocks to malfunction.

Can anyone give me advice on how to implement such a node-level CSE-specific optimisation? Such a thing may be useful for pure functions (as well as when writing things like "4 * n + 4 * n + 4 * n + 4 * n + 4
* n"!).  Thanks in advance.

Gareth aka. Kit

Regarding the "intolerably slow" option, I had the build script running for about 45 minutes as it tried to get through ppc2, and then it crashed with runtime error -1073741819.  Converting this to hexadecimal yields C0000005, which I know from experience is an access violation (usually in the kernel somewhere).

So, long story short, I'm still stuck for now!

Gareth aka. Kit