[llvm-commits] [PATCH] LLVM intrinsic for invariants

[hfinkel at anl.gov]

Adds void @llvm.invariant(i1 %cond)

http://llvm-reviews.chandlerc.com/D178

Files:
  docs/LangRef.html
  include/llvm/Intrinsics.td

Index: docs/LangRef.html
===================================================================
--- docs/LangRef.html
+++ docs/LangRef.html
@@ -330,6 +330,8 @@
           <li><a href="#int_objectsize">
             '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
           <li><a href="#int_expect">
+            '<tt>llvm.invariant</tt>' Intrinsic</a></li>
+          <li><a href="#int_invariant">
             '<tt>llvm.expect</tt>' Intrinsic</a></li>
           <li><a href="#int_donothing">
             '<tt>llvm.donothing</tt>' Intrinsic</a></li>
@@ -9057,6 +9059,34 @@
 
 <!-- _______________________________________________________________________ -->
 <h4>
+  <a name="int_invariant">'<tt>llvm.invariant</tt>' Intrinsic</a>
+</h4>
+
+<div>
+
+<h5>Syntax:</h5>
+<pre>
+  declare void @llvm.invariant(i1 %cond)
+</pre>
+
+<h5>Overview:</h5>
+<p>The '<tt>llvm.invariant</tt>' intrinsic allows the optimizer to assume
+   that the provided condition is true. This information can then be used
+   in simplifying other parts of the code.</p>
+
+<h5>Arguments:</h5>
+
+<p>The condition which the optimizer may assume is always true.</p>
+
+<h5>Semantics:</h5>
+
+<p>The intrinsic allows the optimizer to assume that the provided condition is
+   always true. No code is generated for this intrinsic, and instructions that
+   contribute only to the provided condition are not used for code generation.</p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<h4>
   <a name="int_donothing">'<tt>llvm.donothing</tt>' Intrinsic</a>
 </h4>
 
Index: include/llvm/Intrinsics.td
===================================================================
--- include/llvm/Intrinsics.td
+++ include/llvm/Intrinsics.td
@@ -234,6 +234,8 @@
 
 def int_readcyclecounter : Intrinsic<[llvm_i64_ty]>;
 
+def int_invariant     : Intrinsic<[], [llvm_i1_ty], [IntrNoMem]>;
+
 // Stack Protector Intrinsic - The stackprotector intrinsic writes the stack
 // guard to the correct place on the stack frame.
 def int_stackprotector : Intrinsic<[], [llvm_ptr_ty, llvm_ptrptr_ty], []>;
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