[PATCH] D74989: [LoopTerminology] Loop Simplify Form

[Michael Kruse via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG2a49d650a5d2: [docs][LoopTerminology] Add Loop Simplify Form description. (authored by baziotis, committed by Meinersbur).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D74989/new/

https://reviews.llvm.org/D74989

Files:
  llvm/docs/LoopTerminology.rst
  llvm/docs/Passes.rst


Index: llvm/docs/Passes.rst
===================================================================
--- llvm/docs/Passes.rst
+++ llvm/docs/Passes.rst
@@ -803,12 +803,15 @@
 
 A simple loop rotation transformation.
 
+.. _passes-loop-simplify:
+
 ``-loop-simplify``: Canonicalize natural loops
 ----------------------------------------------
 
 This pass performs several transformations to transform natural loops into a
 simpler form, which makes subsequent analyses and transformations simpler and
-more effective.
+more effective. A summary of it can be found in
+:ref:`Loop Terminology, Loop Simplify Form <loop-terminology-loop-simplify>`.
 
 Loop pre-header insertion guarantees that there is a single, non-critical entry
 edge from outside of the loop to the loop header.  This simplifies a number of
Index: llvm/docs/LoopTerminology.rst
===================================================================
--- llvm/docs/LoopTerminology.rst
+++ llvm/docs/LoopTerminology.rst
@@ -141,10 +141,25 @@
   reachability of the loop.
   
 
+.. _loop-terminology-loop-simplify:
+
 Loop Simplify Form
 ==================
 
-TBD
+The Loop Simplify Form is a canonical form that makes
+several analyses and transformations simpler and more effective.
+It is ensured by the LoopSimplify
+(:ref:`-loop-simplify <passes-loop-simplify>`) pass and is automatically
+added by the pass managers when scheduling a LoopPass.
+This pass is implemented in
+`LoopInfo.h <http://llvm.org/doxygen/LoopSimplify_8h_source.html>`_.
+When it is successful, the loop has:
+
+* A preheader.
+* A single backedge (which implies that there is a single latch).
+* Dedicated exits. That is, no exit block for the loop
+  has a predecessor that is outside the loop. This implies
+  that all exit blocks are dominated by the loop header.
 
 
 Loop Closed SSA (LCSSA)


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