Cache the result of Function::getIntrinsicID() in a DenseMap attached to the LLVMContext.

This reduces the time actually spent doing string to ID conversion and shows a 10% improvement in compile time for a particularly bad case that involves ARM Neon intrinsics (these have many overloads).

Patch by Jean-Luc Duprat!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176365 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 2 deletions

diff --git a/include/llvm/IR/Function.h b/include/llvm/IR/Function.h
index 568b55c87b..a7dea5ca3d 100644
--- a/include/llvm/IR/Function.h
+++ b/include/llvm/IR/Function.h
@@ -113,6 +113,10 @@ private:
   Function(const Function&) LLVM_DELETED_FUNCTION;
   void operator=(const Function&) LLVM_DELETED_FUNCTION;
 
+  /// Do the actual lookup of an intrinsic ID when the query could not be
+  /// answered from the cache.
+  unsigned lookupIntrinsicID() const LLVM_READONLY;
+
   /// Function ctor - If the (optional) Module argument is specified, the
   /// function is automatically inserted into the end of the function list for
   /// the module.
@@ -141,10 +145,12 @@ public:
 
   /// getIntrinsicID - This method returns the ID number of the specified
   /// function, or Intrinsic::not_intrinsic if the function is not an
-  /// instrinsic, or if the pointer is null.  This value is always defined to be
+  /// intrinsic, or if the pointer is null.  This value is always defined to be
   /// zero to allow easy checking for whether a function is intrinsic or not.
   /// The particular intrinsic functions which correspond to this value are
-  /// defined in llvm/Intrinsics.h.
+  /// defined in llvm/Intrinsics.h.  Results are cached in the LLVM context,
+  /// subsequent requests for the same ID return results much faster from the
+  /// cache.
   ///
   unsigned getIntrinsicID() const LLVM_READONLY;
   bool isIntrinsic() const { return getName().startswith("llvm."); }