[llvm-commits] [llvm] r54781 - in /llvm/trunk: lib/CodeGen/MachineInstr.cpp utils/TableGen/RegisterInfoEmitter.cpp

[Owen Anderson]

Author: resistor
Date: Thu Aug 14 13:34:18 2008
New Revision: 54781

URL: http://llvm.org/viewvc/llvm-project?rev=54781&view=rev
Log:
Speed up addRegisterDead by adding more fast checks before performing the expensive 
subregister query, and by increasing the size of the subregister hashtable so
that there are fewer collisions.

Modified:
    llvm/trunk/lib/CodeGen/MachineInstr.cpp
    llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp

Modified: llvm/trunk/lib/CodeGen/MachineInstr.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineInstr.cpp?rev=54781&r1=54780&r2=54781&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/MachineInstr.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineInstr.cpp Thu Aug 14 13:34:18 2008
@@ -834,7 +834,9 @@
       // There exists a super-register that's marked dead.
       if (RegInfo->isSuperRegister(IncomingReg, Reg))
         return true;
-      if (RegInfo->isSubRegister(IncomingReg, Reg))
+      if (RegInfo->getSubRegisters(IncomingReg) &&
+          RegInfo->getSuperRegisters(Reg) &&
+          RegInfo->isSubRegister(IncomingReg, Reg))
         DeadOps.push_back(i);
     }
   }

Modified: llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp?rev=54781&r1=54780&r2=54781&view=diff

==============================================================================
--- llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/RegisterInfoEmitter.cpp Thu Aug 14 13:34:18 2008
@@ -473,10 +473,12 @@
     NumSubRegs += RegisterSubRegs[Regs[i].TheDef].size();
   }
   
-  unsigned SubregHashTableSize = NextPowerOf2(2 * NumSubRegs);
+  unsigned SubregHashTableSize = 2 * NextPowerOf2(2 * NumSubRegs);
   unsigned* SubregHashTable = new unsigned[2 * SubregHashTableSize];
   std::fill(SubregHashTable, SubregHashTable + 2 * SubregHashTableSize, ~0U);
   
+  unsigned hashMisses = 0;
+  
   for (unsigned i = 0, e = Regs.size(); i != e; ++i) {
     Record* R = Regs[i].TheDef;
     for (std::set<Record*>::iterator I = RegisterSubRegs[R].begin(),
@@ -491,6 +493,8 @@
              SubregHashTable[index*2+1] != ~0U) {
         index = (index + ProbeAmt) & (SubregHashTableSize-1);
         ProbeAmt += 2;
+        
+        hashMisses++;
       }
       
       SubregHashTable[index*2] = i;
@@ -498,10 +502,12 @@
     }
   }
   
+  OS << "\n\n  // Number of hash collisions: " << hashMisses << "\n";
+  
   if (SubregHashTableSize) {
     std::string Namespace = Regs[0].TheDef->getValueAsString("Namespace");
     
-    OS << "\n\n  const unsigned SubregHashTable[] = { ";
+    OS << "  const unsigned SubregHashTable[] = { ";
     for (unsigned i = 0; i < SubregHashTableSize - 1; ++i) {
       if (i != 0)
         // Insert spaces for nice formatting.
@@ -527,7 +533,7 @@
     OS << "  const unsigned SubregHashTableSize = "
        << SubregHashTableSize << ";\n";
   } else {
-    OS << "\n\n  const unsigned SubregHashTable[] = { ~0U, ~0U };\n"
+    OS << "  const unsigned SubregHashTable[] = { ~0U, ~0U };\n"
        << "  const unsigned SubregHashTableSize = 1;\n";
   }