Subzero: Register allocator performance improvements and simplifications.

src/IceCfg.cpp

 //===- subzero/src/IceCfg.cpp - Control flow graph implementation ---------===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the Cfg class, including constant pool
@@ skipping 201 matching lines @@
     Node->livenessPostprocess(Mode, getLiveness());
   if (Mode == Liveness_Intervals) {
     // Special treatment for live in-args.  Their liveness needs to
     // extend beyond the beginning of the function, otherwise an arg
     // whose only use is in the first instruction will end up having
     // the trivial live range [1,1) and will *not* interfere with
     // other arguments.  So if the first instruction of the method is
     // "r=arg1+arg2", both args may be assigned the same register.
     for (SizeT I = 0; I < Args.size(); ++I) {
       Variable *Arg = Args[I];
-      if (!Live->getLiveRange(Arg).isEmpty()) {
+      if (!Arg->getLiveRange().isEmpty()) {
         // Add live range [-1,0) with weight 0.  TODO: Here and below,
         // use better symbolic constants along the lines of
         // Inst::NumberDeleted and Inst::NumberSentinel instead of -1
         // and 0.
-        Live->addLiveRange(Arg, -1, 0, 0);
+        Arg->addLiveRange(-1, 0, 0);
       }
       // Do the same for i64 args that may have been lowered into i32
       // Lo and Hi components.
       Variable *Lo = Arg->getLo();
-      if (Lo && !Live->getLiveRange(Lo).isEmpty())
-        Live->addLiveRange(Lo, -1, 0, 0);
+      if (Lo && !Lo->getLiveRange().isEmpty())
+        Lo->addLiveRange(-1, 0, 0);
       Variable *Hi = Arg->getHi();
-      if (Hi && !Live->getLiveRange(Hi).isEmpty())
-        Live->addLiveRange(Hi, -1, 0, 0);
-    }
-    // Copy Liveness::LiveRanges into individual variables.  TODO:
-    // Remove Variable::LiveRange and redirect to
-    // Liveness::LiveRanges.  TODO: make sure Variable weights
-    // are applied properly.
-    SizeT NumVars = Variables.size();
-    for (SizeT i = 0; i < NumVars; ++i) {
-      Variable *Var = Variables[i];
-      Var->setLiveRange(Live->getLiveRange(Var));
-      if (Var->getWeight().isInf())
-        Var->setLiveRangeInfiniteWeight();
+      if (Hi && !Hi->getLiveRange().isEmpty())
+        Hi->addLiveRange(-1, 0, 0);
     }
   }
 }
 
 // Traverse every Variable of every Inst and verify that it
 // appears within the Variable's computed live range.
 bool Cfg::validateLiveness() const {
   TimerMarker T(TimerStack::TT_validateLiveness, this);
   bool Valid = true;
   Ostream &Str = Ctx->getStrDump();
@@ skipping 130 matching lines @@
     }
   }
   // Print each basic block
   for (CfgNode *Node : Nodes)
     Node->dump(this);
   if (getContext()->isVerbose(IceV_Instructions))
     Str << "}\n";
 }
 
 } // end of namespace Ice