From f95ac8a4740d479b38516b9f8ff8be9d89c4952f Mon Sep 17 00:00:00 2001 From: Paul Redmond Date: Thu, 30 May 2013 17:22:46 +0000 Subject: Revise llvm.vectorizer.width documentation - clarify that vectorizer.width only applies if the vectorizer decides to vectorize. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182938 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/LangRef.rst | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'docs/LangRef.rst') diff --git a/docs/LangRef.rst b/docs/LangRef.rst index 72648edbcb..e07d8fe8db 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -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: -- cgit v1.2.3