From 4f4365eb4ec0e1e84a48dbc5bb9f323018facec7 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sat, 25 Apr 2009 21:11:37 +0000 Subject: [PATCH] Update docs to not mention gcse/loadvn and mention memdep and new stuff. PR3924. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70077 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/AliasAnalysis.html | 36 ++++++++++++------------------------ 1 file changed, 12 insertions(+), 24 deletions(-) diff --git a/docs/AliasAnalysis.html b/docs/AliasAnalysis.html index 97a813344d8..a89903d2af8 100644 --- a/docs/AliasAnalysis.html +++ b/docs/AliasAnalysis.html @@ -36,7 +36,7 @@
  • Using alias analysis results @@ -537,16 +537,16 @@ preference, these are...

    -

    The load-vn pass uses alias analysis to provide value numbering -information for load instructions and pointer values. If your analysis -or transformation can be modeled in a form that uses value numbering -information, you don't have to do anything special to handle load instructions: -just use the load-vn pass, which uses alias analysis.

    +

    The memdep pass uses alias analysis to provide high-level dependence +information about memory-using instructions. This will tell you which store +feeds into a load, for example. It uses caching and other techniques to be +efficient, and is used by Dead Store Elimination, GVN, and memcpy optimizations. +

    @@ -710,7 +710,7 @@ aggressive local analysis that "knows" many important facts:

    for internal global variables that don't "have their address taken". If a global does not have its address taken, the pass knows that no pointers alias the global. This pass also keeps track of functions that it knows never access -memory or never read memory. This allows certain optimizations (e.g. GCSE) to +memory or never read memory. This allows certain optimizations (e.g. GVN) to eliminate call instructions entirely.

    @@ -855,26 +855,14 @@ pointer.

    -

    The -load-vn pass uses alias analysis to "value -number" loads and pointers values, which is used by the GCSE pass to -eliminate instructions. The -load-vn pass relies on alias information -and must-alias information. This combination of passes can make the following -transformations:

    - -
      -
    • Redundant load instructions are eliminated.
    • -
    • Load instructions that follow a store to the same location are replaced with -the stored value ("store forwarding").
    • -
    • Pointers values (e.g. formal arguments) that must-alias simpler expressions -(e.g. global variables or the null pointer) are replaced. Note that this -implements transformations like "virtual method resolution", turning indirect -calls into direct calls.
    • -
    +

    These passes use AliasAnalysis information to reason about loads and stores. +