[all-commits] [llvm/llvm-project] c4048d: [SCEV] Attempt to define what flags are legal on a...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: c4048d8f50aaf2c4c13b8d3e138abc34a22da754
      https://github.com/llvm/llvm-project/commit/c4048d8f50aaf2c4c13b8d3e138abc34a22da754
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2021-09-14 (Tue, 14 Sep 2021)

  Changed paths:
    M llvm/include/llvm/Analysis/ScalarEvolution.h

  Log Message:
  -----------
  [SCEV] Attempt to define what flags are legal on a SCEV

This is an attempt to define what the current semantics are closest too.  Unfortunately, the current implementation does appear to be inconsistent with all semantic variants we've considered.  This semantics is the one which seems to be closest to the spirit of the code, and that matched several long time contributors mental models of how the code "should work".

https://bugs.llvm.org/show_bug.cgi?id=51817 tracks the list of currently known violations of these rules.  A series of follow up patches will be addressing each now that we've defined them to be bugs.

Differential Revision: https://reviews.llvm.org/D109553