[llvm-commits] [llvm] r68888 - in /llvm/trunk: include/llvm/CodeGen/FastISel.h lib/CodeGen/SelectionDAG/FastISel.cpp

[Chris Lattner]

Author: lattner
Date: Sun Apr 12 02:45:01 2009
New Revision: 68888

URL: http://llvm.org/viewvc/llvm-project?rev=68888&view=rev
Log:
optimize FastISel::UpdateValueMap to avoid duplicate map lookups,
and make it return the assigned register.

Modified:
    llvm/trunk/include/llvm/CodeGen/FastISel.h
    llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp

Modified: llvm/trunk/include/llvm/CodeGen/FastISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/FastISel.h?rev=68888&r1=68887&r2=68888&view=diff

==============================================================================
--- llvm/trunk/include/llvm/CodeGen/FastISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/FastISel.h Sun Apr 12 02:45:01 2009
@@ -279,7 +279,7 @@
   /// the CFG.
   void FastEmitBranch(MachineBasicBlock *MBB);
 
-  void UpdateValueMap(Value* I, unsigned Reg);
+  unsigned UpdateValueMap(Value* I, unsigned Reg);
 
   unsigned createResultReg(const TargetRegisterClass *RC);
   

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp?rev=68888&r1=68887&r2=68888&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp Sun Apr 12 02:45:01 2009
@@ -149,16 +149,21 @@
 /// NOTE: This is only necessary because we might select a block that uses
 /// a value before we select the block that defines the value.  It might be
 /// possible to fix this by selecting blocks in reverse postorder.
-void FastISel::UpdateValueMap(Value* I, unsigned Reg) {
+unsigned FastISel::UpdateValueMap(Value* I, unsigned Reg) {
   if (!isa<Instruction>(I)) {
     LocalValueMap[I] = Reg;
-    return;
+    return Reg;
   }
-  if (!ValueMap.count(I))
-    ValueMap[I] = Reg;
-  else
-    TII.copyRegToReg(*MBB, MBB->end(), ValueMap[I],
-                     Reg, MRI.getRegClass(Reg), MRI.getRegClass(Reg));
+  
+  unsigned &AssignedReg = ValueMap[I];
+  if (AssignedReg == 0)
+    AssignedReg = Reg;
+  else {
+    const TargetRegisterClass *RegClass = MRI.getRegClass(Reg);
+    TII.copyRegToReg(*MBB, MBB->end(), AssignedReg,
+                     Reg, RegClass, RegClass);
+  }
+  return AssignedReg;
 }
 
 unsigned FastISel::getRegForGEPIndex(Value *Idx) {