[llvm-commits] [llvm] r143135 - in /llvm/trunk: docs/LangRef.html include/llvm/LLVMContext.h lib/VMCore/LLVMContext.cpp

[Peter Collingbourne]

Author: pcc
Date: Thu Oct 27 14:19:14 2011
New Revision: 143135

URL: http://llvm.org/viewvc/llvm-project?rev=143135&view=rev
Log:
Add a pinned metadata name for fpaccuracy, and document it

Modified:
    llvm/trunk/docs/LangRef.html
    llvm/trunk/include/llvm/LLVMContext.h
    llvm/trunk/lib/VMCore/LLVMContext.cpp

Modified: llvm/trunk/docs/LangRef.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.html?rev=143135&r1=143134&r2=143135&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.html (original)
+++ llvm/trunk/docs/LangRef.html Thu Oct 27 14:19:14 2011
@@ -103,6 +103,7 @@
       <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
         <ol>
           <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
+          <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
         </ol>
       </li>
     </ol>
@@ -2966,6 +2967,35 @@
 
 </div>
 
+<h4>
+  <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
+</h4>
+ 
+<div>
+
+<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
+   point type.  It expresses the maximum relative error of the result of
+   that instruction, in ULPs. ULP is defined as follows:</p>
+
+<blockquote><p>
+If x is a real number that lies between two finite consecutive floating-point
+numbers a and b, without being equal to one of them, then ulp(x) = |b - a|,
+otherwise ulp(x) is the distance between the two non-equal finite
+floating-point numbers nearest x. Moreover, ulp(NaN) is NaN.
+</p></blockquote>
+
+<p>The maximum relative error may be any rational number.  The metadata node
+   shall consist of a pair of unsigned integers respectively representing
+   the numerator and denominator.  For example, 2.5 ULP:</p>
+
+<div class="doc_code">
+<pre>
+!0 = metadata !{ i32 5, i32 2 }
+</pre>
+</div>
+
+</div>
+
 </div>
 
 </div>

Modified: llvm/trunk/include/llvm/LLVMContext.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LLVMContext.h?rev=143135&r1=143134&r2=143135&view=diff
==============================================================================
--- llvm/trunk/include/llvm/LLVMContext.h (original)
+++ llvm/trunk/include/llvm/LLVMContext.h Thu Oct 27 14:19:14 2011
@@ -40,7 +40,8 @@
   enum {
     MD_dbg = 0,  // "dbg"
     MD_tbaa = 1, // "tbaa"
-    MD_prof = 2  // "prof"
+    MD_prof = 2,  // "prof"
+    MD_fpaccuracy = 3  // "fpaccuracy"
   };
   
   /// getMDKindID - Return a unique non-zero ID for the specified metadata kind.

Modified: llvm/trunk/lib/VMCore/LLVMContext.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/LLVMContext.cpp?rev=143135&r1=143134&r2=143135&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/LLVMContext.cpp (original)
+++ llvm/trunk/lib/VMCore/LLVMContext.cpp Thu Oct 27 14:19:14 2011
@@ -43,6 +43,11 @@
   // Create the 'prof' metadata kind.
   unsigned ProfID = getMDKindID("prof");
   assert(ProfID == MD_prof && "prof kind id drifted"); (void)ProfID;
+
+  // Create the 'fpaccuracy' metadata kind.
+  unsigned FPAccuracyID = getMDKindID("fpaccuracy");
+  assert(FPAccuracyID == MD_fpaccuracy && "fpaccuracy kind id drifted");
+  (void)FPAccuracyID;
 }
 LLVMContext::~LLVMContext() { delete pImpl; }