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| author | Dan Gohman <gohman@apple.com> | 2010-07-06 15:26:33 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2010-07-06 15:26:33 +0000 |
| commit | ff70fe40aa64ed260aaff5f77151c3c2fb39b75a (patch) | |
| tree | 8aaea07d33def54d8ae22f8d9884927bf5d90de6 /docs | |
| parent | 36335be3b95f856b7eb7e0766e01ba423315e1ab (diff) | |
| download | llvm-ff70fe40aa64ed260aaff5f77151c3c2fb39b75a.tar.gz llvm-ff70fe40aa64ed260aaff5f77151c3c2fb39b75a.tar.bz2 llvm-ff70fe40aa64ed260aaff5f77151c3c2fb39b75a.tar.xz | |
Note the relationship between C99 restrict and LLVM noalias, and
clarify a few other things.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107659 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/GetElementPtr.html | 6 | ||||
| -rw-r--r-- | docs/LangRef.html | 13 |
2 files changed, 15 insertions, 4 deletions
diff --git a/docs/GetElementPtr.html b/docs/GetElementPtr.html index 1bf6f432de..3bf38a366d 100644 --- a/docs/GetElementPtr.html +++ b/docs/GetElementPtr.html @@ -64,7 +64,8 @@ <div class="doc_text"> <p>This document seeks to dispel the mystery and confusion surrounding LLVM's - GetElementPtr (GEP) instruction. Questions about the wily GEP instruction are + <a href="LangRef.html#i_getelementptr">GetElementPtr</a> (GEP) instruction. + Questions about the wily GEP instruction are probably the most frequently occurring questions once a developer gets down to coding with LLVM. Here we lay out the sources of confusion and show that the GEP instruction is really quite simple. @@ -653,7 +654,8 @@ idx3 = (char*) &MyVar + 8 <li>Support C, C-like languages, and languages which can be conceptually lowered into C (this covers a lot).</li> <li>Support optimizations such as those that are common in - C compilers.</li> + C compilers. In particular, GEP is a cornerstone of LLVM's + <a href="LangRef.html#pointeraliasing">pointer aliasing model</a>.</li> <li>Provide a consistent method for computing addresses so that address computations don't need to be a part of load and store instructions in the IR.</li> diff --git a/docs/LangRef.html b/docs/LangRef.html index ad730deffb..f8a2643803 100644 --- a/docs/LangRef.html +++ b/docs/LangRef.html @@ -1062,7 +1062,15 @@ declare signext i8 @returns_signed_char() The caller shares the responsibility with the callee for ensuring that these requirements are met. For further details, please see the discussion of the NoAlias response in - <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.</dd> + <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br> +<br> + Note that this definition of <tt>noalias<tt> is intentionally + similar to the definition of <tt>restrict<tt> in C99 for function + arguments, thought it is slightly weaker. +<br> + For function return values, C99's <tt>restrict</tt> is not meaningful, + while LLVM's <tt>noalias</tt> is. + </dd> <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt> <dd>This indicates that the callee does not make any copies of the pointer @@ -2397,7 +2405,8 @@ has undefined behavior.</p> <li>An instruction with externally visible side effects depends on the most recent preceding instruction with externally visible side effects, following - the order in the IR. (This includes volatile loads and stores.)</li> + the order in the IR. (This includes + <a href="#volatile">volatile operations</a>.)</li> <li>An instruction <i>control-depends</i> on a <a href="#terminators">terminator instruction</a> |