Reapply 105986 with fix for bug pointed out by Jakob:

[oota-llvm.git] / lib / Target / TargetRegisterInfo.cpp

diff --git a/lib/Target/TargetRegisterInfo.cpp b/lib/Target/TargetRegisterInfo.cpp
index ec2248a6b84c2652f356cb7b580353493923faa7..32299f6c7e0f666a6d8c16cb6bb92f2689325731 100644 (file)
--- a/lib/Target/TargetRegisterInfo.cpp
+++ b/lib/Target/TargetRegisterInfo.cpp
@@ -25,10 +25,8 @@ TargetRegisterInfo::TargetRegisterInfo(const TargetRegisterDesc *D, unsigned NR,
                              const char *const *subregindexnames,
                              int CFSO, int CFDO,
                              const unsigned* subregs, const unsigned subregsize,
-                         const unsigned* superregs, const unsigned superregsize,
                          const unsigned* aliases, const unsigned aliasessize)
   : SubregHash(subregs), SubregHashSize(subregsize),
-    SuperregHash(superregs), SuperregHashSize(superregsize),
     AliasesHash(aliases), AliasesHashSize(aliasessize),
     Desc(D), SubRegIndexNames(subregindexnames), NumRegs(NR),
     RegClassBegin(RCB), RegClassEnd(RCE) {
@@ -62,6 +60,25 @@ TargetRegisterInfo::getPhysicalRegisterRegClass(unsigned reg, EVT VT) const {
   return BestRC;
 }
 
+/// getMinimalPhysRegClass - Returns the Register Class of a physical
+/// register of the given type.
+const TargetRegisterClass *
+TargetRegisterInfo::getMinimalPhysRegClass(unsigned reg) const {
+  assert(isPhysicalRegister(reg) && "reg must be a physical register");
+
+  // Pick the most sub register class of the right type that contains
+  // this physreg.
+  const TargetRegisterClass* BestRC = 0;
+  for (regclass_iterator I = regclass_begin(), E = regclass_end(); I != E; ++I){
+    const TargetRegisterClass* RC = *I;
+    if (RC->contains(reg) && (!BestRC || BestRC->hasSubClass(RC)))
+      BestRC = RC;
+  }
+
+  assert(BestRC && "Couldn't find the register class");
+  return BestRC;
+}
+
 /// getAllocatableSetForRC - Toggle the bits that represent allocatable
 /// registers for the specific register class.
 static void getAllocatableSetForRC(const MachineFunction &MF,