[llvm] r182938 - Revise llvm.vectorizer.width documentation

[Paul Redmond]

Author: predmond
Date: Thu May 30 12:22:46 2013
New Revision: 182938

URL: http://llvm.org/viewvc/llvm-project?rev=182938&view=rev
Log:
Revise llvm.vectorizer.width documentation

- clarify that vectorizer.width only applies if the vectorizer decides to
  vectorize.

Modified:
    llvm/trunk/docs/LangRef.rst

Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=182938&r1=182937&r2=182938&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Thu May 30 12:22:46 2013
@@ -2680,8 +2680,10 @@ determined automatically.
 '``llvm.vectorizer.width``' Metadata
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-This metadata forces the loop vectorizer to widen scalar values to a vector
-width of ``N`` rather than computing the width using a cost model.
+This metadata sets the target width of the vectorizer to ``N``. Without
+this metadata, the vectorizer will choose a width automatically.
+Regardless of this metadata, the vectorizer will only vectorize loops if
+it believes it is valid to do so.
 
 The first operand is the string ``llvm.vectorizer.width`` and the second
 operand is an integer specifying the width. For example: