From f846f16c92590379e900d01812e828e83b759cee Mon Sep 17 00:00:00 2001
From: Michael Ilseman <milseman@apple.com>
Date: Wed, 19 Dec 2012 23:17:20 +0000
Subject: [PATCH] Refactor isIntrinsic() to be quicker, and change classof()
 (and thus, isa<IntrinsicInst>()) to use it. This decreases the number of
 occurrences of the slow-path string matching performed by getIntrinsicID().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170602 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Function.h      | 2 +-
 include/llvm/IntrinsicInst.h | 2 +-
 lib/VMCore/Function.cpp      | 6 +-----
 3 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/include/llvm/Function.h b/include/llvm/Function.h
index ce7ae2646bf..2f555e89d8e 100644
--- a/include/llvm/Function.h
+++ b/include/llvm/Function.h
@@ -147,7 +147,7 @@ public:
   /// defined in llvm/Intrinsics.h.
   ///
   unsigned getIntrinsicID() const LLVM_READONLY;
-  bool isIntrinsic() const { return getIntrinsicID() != 0; }
+  bool isIntrinsic() const { return getName().startswith("llvm."); }
 
   /// getCallingConv()/setCallingConv(CC) - These method get and set the
   /// calling convention of this function.  The enum values for the known
diff --git a/include/llvm/IntrinsicInst.h b/include/llvm/IntrinsicInst.h
index d5d27e6998f..41e79e9ee3e 100644
--- a/include/llvm/IntrinsicInst.h
+++ b/include/llvm/IntrinsicInst.h
@@ -47,7 +47,7 @@ namespace llvm {
     // Methods for support type inquiry through isa, cast, and dyn_cast:
     static inline bool classof(const CallInst *I) {
       if (const Function *CF = I->getCalledFunction())
-        return CF->getIntrinsicID() != 0;
+        return CF->isIntrinsic();
       return false;
     }
     static inline bool classof(const Value *V) {
diff --git a/lib/VMCore/Function.cpp b/lib/VMCore/Function.cpp
index cd3b663ac8d..5ff088e7f56 100644
--- a/lib/VMCore/Function.cpp
+++ b/lib/VMCore/Function.cpp
@@ -326,15 +326,11 @@ void Function::copyAttributesFrom(const GlobalValue *Src) {
 ///
 unsigned Function::getIntrinsicID() const {
   const ValueName *ValName = this->getValueName();
-  if (!ValName)
+  if (!ValName || !isIntrinsic())
     return 0;
   unsigned Len = ValName->getKeyLength();
   const char *Name = ValName->getKeyData();
 
-  if (Len < 5 || Name[4] != '.' || Name[0] != 'l' || Name[1] != 'l'
-      || Name[2] != 'v' || Name[3] != 'm')
-    return 0;  // All intrinsics start with 'llvm.'
-
 #define GET_FUNCTION_RECOGNIZER
 #include "llvm/Intrinsics.gen"
 #undef GET_FUNCTION_RECOGNIZER