[PATCH] use register iterators that include self to reduce code duplication in CriticalAntiDepBreaker

[Sanjay Patel]

Closed by commit rL214973 (authored by @spatel).

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D4566

Files:
  llvm/trunk/lib/CodeGen/CriticalAntiDepBreaker.cpp

Index: llvm/trunk/lib/CodeGen/CriticalAntiDepBreaker.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/CriticalAntiDepBreaker.cpp
+++ llvm/trunk/lib/CodeGen/CriticalAntiDepBreaker.cpp
@@ -262,19 +262,10 @@
       // Ignore two-addr defs.
       if (MI->isRegTiedToUseOperand(i)) continue;
 
-      // FIXME: we should use a SubRegIterator that includes self (as above), so
-      // we don't have to repeat all this code for the reg itself.
-      DefIndices[Reg] = Count;
-      KillIndices[Reg] = ~0u;
-      assert(((KillIndices[Reg] == ~0u) !=
-              (DefIndices[Reg] == ~0u)) &&
-             "Kill and Def maps aren't consistent for Reg!");
-      KeepRegs.reset(Reg);
-      Classes[Reg] = nullptr;
-      RegRefs.erase(Reg);
-      // Repeat, for all subregs.
-      for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs) {
-        unsigned SubregReg = *SubRegs;
+      // For the reg itself and all subregs: update the def to current;
+      // reset the kill state, any restrictions, and references.
+      for (MCSubRegIterator SRI(Reg, TRI, true); SRI.isValid(); ++SRI) {
+        unsigned SubregReg = *SRI;
         DefIndices[SubregReg] = Count;
         KillIndices[SubregReg] = ~0u;
         KeepRegs.reset(SubregReg);
@@ -306,19 +297,9 @@
 
     RegRefs.insert(std::make_pair(Reg, &MO));
 
-    // FIXME: we should use an MCRegAliasIterator that includes self so we don't
-    // have to repeat all this code for the reg itself.
-    
     // It wasn't previously live but now it is, this is a kill.
-    if (KillIndices[Reg] == ~0u) {
-      KillIndices[Reg] = Count;
-      DefIndices[Reg] = ~0u;
-          assert(((KillIndices[Reg] == ~0u) !=
-                  (DefIndices[Reg] == ~0u)) &&
-               "Kill and Def maps aren't consistent for Reg!");
-    }
-    // Repeat, for all aliases.
-    for (MCRegAliasIterator AI(Reg, TRI, false); AI.isValid(); ++AI) {
+    // Repeat for all aliases.
+    for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) {
       unsigned AliasReg = *AI;
       if (KillIndices[AliasReg] == ~0u) {
         KillIndices[AliasReg] = Count;
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