forked from OSchip/llvm-project
Add a pinned metadata name for fpaccuracy, and document it
llvm-svn: 143135
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@ -103,6 +103,7 @@
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<li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
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<ol>
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<li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
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<li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
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</ol>
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</li>
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</ol>
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@ -2966,6 +2967,35 @@ call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
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</div>
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<h4>
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<a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
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</h4>
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<div>
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<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
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point type. It expresses the maximum relative error of the result of
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that instruction, in ULPs. ULP is defined as follows:</p>
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<blockquote><p>
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If x is a real number that lies between two finite consecutive floating-point
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numbers a and b, without being equal to one of them, then ulp(x) = |b - a|,
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otherwise ulp(x) is the distance between the two non-equal finite
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floating-point numbers nearest x. Moreover, ulp(NaN) is NaN.
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</p></blockquote>
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<p>The maximum relative error may be any rational number. The metadata node
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shall consist of a pair of unsigned integers respectively representing
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the numerator and denominator. For example, 2.5 ULP:</p>
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<div class="doc_code">
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<pre>
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!0 = metadata !{ i32 5, i32 2 }
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</pre>
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</div>
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</div>
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</div>
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</div>
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@ -40,7 +40,8 @@ public:
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enum {
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MD_dbg = 0, // "dbg"
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MD_tbaa = 1, // "tbaa"
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MD_prof = 2 // "prof"
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MD_prof = 2, // "prof"
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MD_fpaccuracy = 3 // "fpaccuracy"
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};
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/// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
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@ -43,6 +43,11 @@ LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
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// Create the 'prof' metadata kind.
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unsigned ProfID = getMDKindID("prof");
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assert(ProfID == MD_prof && "prof kind id drifted"); (void)ProfID;
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// Create the 'fpaccuracy' metadata kind.
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unsigned FPAccuracyID = getMDKindID("fpaccuracy");
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assert(FPAccuracyID == MD_fpaccuracy && "fpaccuracy kind id drifted");
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(void)FPAccuracyID;
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}
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LLVMContext::~LLVMContext() { delete pImpl; }
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