[RDF] Cache register aliases in PhysicalRegisterInfo

This improves performance of PhysicalRegisterInfo::makeRegRef.

Author: Krzysztof Parzyszek

llvm/include/llvm/CodeGen/RDFRegisters.h

@@ -132,6 +132,10 @@ namespace rdf {
       return MaskInfos[Register::stackSlot2Index(MaskId)].Units;
     }
 
+    const BitVector &getUnitAliases(uint32_t U) const {
+      return AliasInfos[U].Regs;
+    }
+
     RegisterRef mapTo(RegisterRef RR, unsigned R) const;
     const TargetRegisterInfo &getTRI() const { return TRI; }
 
@@ -146,12 +150,16 @@ namespace rdf {
     struct MaskInfo {
       BitVector Units;
     };
+    struct AliasInfo {
+      BitVector Regs;
+    };
 
     const TargetRegisterInfo &TRI;
     IndexedSet<const uint32_t*> RegMasks;
     std::vector<RegInfo> RegInfos;
     std::vector<UnitInfo> UnitInfos;
     std::vector<MaskInfo> MaskInfos;
+    std::vector<AliasInfo> AliasInfos;
 
     bool aliasRR(RegisterRef RA, RegisterRef RB) const;
     bool aliasRM(RegisterRef RR, RegisterRef RM) const;

llvm/lib/CodeGen/RDFRegisters.cpp

@@ -92,6 +92,15 @@ PhysicalRegisterInfo::PhysicalRegisterInfo(const TargetRegisterInfo &tri,
     }
     MaskInfos[M].Units = PU.flip();
   }
+
+  AliasInfos.resize(TRI.getNumRegUnits());
+  for (uint32_t U = 0, NU = TRI.getNumRegUnits(); U != NU; ++U) {
+    BitVector AS(TRI.getNumRegs());
+    for (MCRegUnitRootIterator R(U, &TRI); R.isValid(); ++R)
+      for (MCSuperRegIterator S(*R, &TRI, true); S.isValid(); ++S)
+        AS.set(*S);
+    AliasInfos[U].Regs = AS;
+  }
 }
 
 std::set<RegisterId> PhysicalRegisterInfo::getAliasSet(RegisterId Reg) const {
@@ -317,26 +326,17 @@ RegisterRef RegisterAggr::makeRegRef() const {
   if (U < 0)
     return RegisterRef();
 
-  auto AliasedRegs = [this] (uint32_t Unit, BitVector &Regs) {
-    for (MCRegUnitRootIterator R(Unit, &PRI.getTRI()); R.isValid(); ++R)
-      for (MCSuperRegIterator S(*R, &PRI.getTRI(), true); S.isValid(); ++S)
-        Regs.set(*S);
-  };
-
   // Find the set of all registers that are aliased to all the units
   // in this aggregate.
 
   // Get all the registers aliased to the first unit in the bit vector.
-  BitVector Regs(PRI.getTRI().getNumRegs());
-  AliasedRegs(U, Regs);
+  BitVector Regs = PRI.getUnitAliases(U);
   U = Units.find_next(U);
 
   // For each other unit, intersect it with the set of all registers
   // aliased that unit.
   while (U >= 0) {
-    BitVector AR(PRI.getTRI().getNumRegs());
-    AliasedRegs(U, AR);
-    Regs &= AR;
+    Regs &= PRI.getUnitAliases(U);
     U = Units.find_next(U);
   }