[llvm-commits] [llvm] r113016 - /llvm/trunk/lib/CodeGen/RegAllocFast.cpp

[Jim Grosbach]

Author: grosbach
Date: Fri Sep  3 16:45:15 2010
New Revision: 113016

URL: http://llvm.org/viewvc/llvm-project?rev=113016&view=rev
Log:
previous patch was a little too tricky for its own good. Don't try to
overload UserInInstr. Explicitly check Allocatable. The early exit in the
condition will mean the performance impact of the extra test should be
minimal.

Modified:
    llvm/trunk/lib/CodeGen/RegAllocFast.cpp

Modified: llvm/trunk/lib/CodeGen/RegAllocFast.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocFast.cpp?rev=113016&r1=113015&r2=113016&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocFast.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocFast.cpp Fri Sep  3 16:45:15 2010
@@ -113,9 +113,6 @@
     // Allocatable - vector of allocatable physical registers.
     BitVector Allocatable;
 
-    // Reserved - vector of reserved physical registers.
-    BitVector Reserved;
-
     // SkippedInstrs - Descriptors of instructions whose clobber list was
     // ignored because all registers were spilled. It is still necessary to
     // mark all the clobbered registers as used by the function.
@@ -501,7 +498,8 @@
   // First try to find a completely free register.
   for (TargetRegisterClass::iterator I = AOB; I != AOE; ++I) {
     unsigned PhysReg = *I;
-    if (PhysRegState[PhysReg] == regFree && !UsedInInstr.test(PhysReg))
+    if (PhysRegState[PhysReg] == regFree && !UsedInInstr.test(PhysReg) &&
+        Allocatable.test(PhysReg))
       return assignVirtToPhysReg(LRE, PhysReg);
   }
 
@@ -510,6 +508,8 @@
 
   unsigned BestReg = 0, BestCost = spillImpossible;
   for (TargetRegisterClass::iterator I = AOB; I != AOE; ++I) {
+    if (!Allocatable.test(*I))
+      continue;
     unsigned Cost = calcSpillCost(*I);
     // Cost is 0 when all aliases are already disabled.
     if (Cost == 0)
@@ -712,7 +712,7 @@
   }
 
   // Restore UsedInInstr to a state usable for allocating normal virtual uses.
-  UsedInInstr = Reserved;
+  UsedInInstr.reset();
   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
     MachineOperand &MO = MI->getOperand(i);
     if (!MO.isReg() || (MO.isDef() && !MO.isEarlyClobber())) continue;
@@ -838,7 +838,7 @@
     }
 
     // Track registers used by instruction.
-    UsedInInstr = Reserved;
+    UsedInInstr.reset();
 
     // First scan.
     // Mark physreg uses and early clobbers as used.
@@ -916,7 +916,7 @@
 
     // Track registers defined by instruction - early clobbers and tied uses at
     // this point.
-    UsedInInstr = Reserved;
+    UsedInInstr.reset();
     if (hasEarlyClobbers) {
       for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
         MachineOperand &MO = MI->getOperand(i);
@@ -1014,7 +1014,6 @@
 
   UsedInInstr.resize(TRI->getNumRegs());
   Allocatable = TRI->getAllocatableSet(*MF);
-  Reserved = TRI->getReservedRegs(*MF);
 
   // initialize the virtual->physical register map to have a 'null'
   // mapping for all virtual registers