[PATCH] D76273: [NFCI][SCEV] Avoid recursion in SCEVExpander::isHighCostExpansion*()

Wed Mar 18 04:19:04 PDT 2020

lebedev.ri marked 3 inline comments as done.
lebedev.ri added a comment.

In D76273#1928590 <https://reviews.llvm.org/D76273#1928590>, @mkazantsev wrote:

> LGTM

Thank you for the review!

In D76273#1928615 <https://reviews.llvm.org/D76273#1928615>, @mkazantsev wrote:

> As a suggestion: since this helper doesn't create new code, it doesn't seem to be important whether it is FIFO or LIFO. If that is so, I'd suggest using SmallVector and LIFO algorithm instead. It should have better memory footprint. OK if it does as follow-up.

I agree the order doesn't matter for correctness.
Currently we seem to be doing depth-first traversal (since we recurse before looking at other operands).
I don't have any evidence which approach is better in the sense that it would exhaust the budget faster,
so i'll go back to simple smallvector with back-insertion/extraction.

Repository:
  rG LLVM Github Monorepo

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https://reviews.llvm.org/D76273