From 7ed9ea81f8b4ec26c27da73ea9ad0e84337a3e4a Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Fri, 11 Aug 2006 23:55:53 +0000
Subject: [PATCH] Switch NodeID to track 32-bit chunks instead of 8-bit chunks,
 for a 2.5% speedup in isel time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29640 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/SelectionDAGCSEMap.h     | 25 +++++++------------
 .../SelectionDAG/SelectionDAGCSEMap.cpp       | 24 +++++++-----------
 2 files changed, 18 insertions(+), 31 deletions(-)

diff --git a/include/llvm/CodeGen/SelectionDAGCSEMap.h b/include/llvm/CodeGen/SelectionDAGCSEMap.h
index 42007fdf688..c44d09b010c 100644
--- a/include/llvm/CodeGen/SelectionDAGCSEMap.h
+++ b/include/llvm/CodeGen/SelectionDAGCSEMap.h
@@ -63,7 +63,7 @@ namespace llvm {
     class NodeID {
       /// Use a SmallVector to avoid a heap allocation in the common case.
       ///
-      SmallVector<unsigned char, 256> Bits;
+      SmallVector<unsigned, 32> Bits;
     public:
       NodeID() {}
       NodeID(SDNode *N);
@@ -77,13 +77,13 @@ namespace llvm {
              const SDOperand *OpList, unsigned N);
       
       void SetOpcode(unsigned short ID) {
-        Bits.push_back(ID & 0xFF);
-        Bits.push_back(ID >> 8);
+        Bits.push_back(ID);
       }
       
-      /// getOpcode - If the opcode has been set for this NodeID, return it.
+      /// getOpcode - Return the opcode that has been set for this NodeID.
+      ///
       unsigned getOpcode() const {
-        return Bits[0] + (Bits[1] << 8);
+        return Bits[0];
       }
 
       void SetValueTypes(const void *VTList) { AddPointer(VTList); }
@@ -99,21 +99,14 @@ namespace llvm {
       void AddOperand(SDOperand Op);
       void AddPointer(const void *Ptr);
       void AddInteger(signed I) {
-        Bits.push_back((I >>  0) & 0xFF);
-        Bits.push_back((I >>  8) & 0xFF);
-        Bits.push_back((I >> 16) & 0xFF);
-        Bits.push_back((I >> 24) & 0xFF);
+        Bits.push_back(I);
       }
       void AddInteger(unsigned I) {
-        AddInteger((signed)I);
+        Bits.push_back(I);
       }
       void AddInteger(uint64_t I) {
-        union {
-          uint64_t x;
-          unsigned char A[8];
-        };
-        x = I;
-        Bits.append(A, A+8);
+        Bits.push_back(unsigned(I));
+        Bits.push_back(unsigned(I >> 32));
       }
       
       unsigned ComputeHash() const;
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGCSEMap.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGCSEMap.cpp
index 6fc6a48b1e4..0a02333522a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGCSEMap.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGCSEMap.cpp
@@ -105,21 +105,15 @@ void SelectionDAGCSEMap::NodeID::AddPointer(const void *Ptr) {
   // on the host.  It doesn't matter however, because hashing on pointer values
   // in inherently unstable.  Nothing in the SelectionDAG should depend on the
   // ordering of nodes in the CSEMap.
-  union {
-    intptr_t PtrI;
-    unsigned char PtrA[sizeof(intptr_t)];
-  };
-  PtrI = (intptr_t)Ptr;
-  Bits.append(PtrA, PtrA+sizeof(intptr_t));
+  intptr_t PtrI = (intptr_t)Ptr;
+  Bits.push_back(unsigned(PtrI));
+  if (sizeof(intptr_t) > sizeof(unsigned))
+    Bits.push_back(unsigned(uint64_t(PtrI) >> 32));
 }
 
 void SelectionDAGCSEMap::NodeID::AddOperand(SDOperand Op) {
   AddPointer(Op.Val);
-  // 2 bytes of resno might be too small, three should certainly be enough. :)
-  assert(Op.ResNo < (1 << 24) && "ResNo too large for CSE Map to handle!");
-  Bits.push_back((Op.ResNo >>  0) & 0xFF);
-  Bits.push_back((Op.ResNo >>  8) & 0xFF);
-  Bits.push_back((Op.ResNo >> 16) & 0xFF);
+  Bits.push_back(Op.ResNo);
 }
 
 void SelectionDAGCSEMap::NodeID::SetOperands(const SDOperand *Ops, 
@@ -135,13 +129,13 @@ unsigned SelectionDAGCSEMap::NodeID::ComputeHash() const {
   // FIXME: this hash function sucks.
   unsigned Hash = 0;
   for (unsigned i = 0, e = Bits.size(); i != e; ++i)
-    Hash += Bits[i];
+    Hash = Hash+Bits[i];
   return Hash;
 }
 
 bool SelectionDAGCSEMap::NodeID::operator==(const NodeID &RHS) const {
   if (Bits.size() != RHS.Bits.size()) return false;
-  return memcmp(&Bits[0], &RHS.Bits[0], Bits.size()) == 0;
+  return memcmp(&Bits[0], &RHS.Bits[0], Bits.size()*sizeof(Bits[0])) == 0;
 }
 
 
@@ -169,8 +163,8 @@ SDNode *SelectionDAGCSEMap::GetNextPtr(void *NextInBucketPtr) {
 }
 
 void **SelectionDAGCSEMap::GetBucketPtr(void *NextInBucketPtr) {
-  assert(NextInBucketPtr >= Buckets && NextInBucketPtr < Buckets+NumBuckets &&
-         "NextInBucketPtr is not a bucket ptr");
+  //assert(NextInBucketPtr >= Buckets && NextInBucketPtr < Buckets+NumBuckets &&
+  //       "NextInBucketPtr is not a bucket ptr");
   return static_cast<void**>(NextInBucketPtr);
 }
 
-- 
2.34.1