EXTRACT_SUBREG coalescing support. The coalescer now treats EXTRACT_SUBREG like

(almost) a register copy. However, it always coalesced to the register of the
RHS (the super-register). All uses of the result of a EXTRACT_SUBREG are sub-
register uses which adds subtle complications to load folding, spiller rewrite,
etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42899 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/SSARegMap.h b/include/llvm/CodeGen/SSARegMap.h
index 97d8d69..a92222a 100644
--- a/include/llvm/CodeGen/SSARegMap.h
+++ b/include/llvm/CodeGen/SSARegMap.h
@@ -26,6 +26,7 @@ class TargetRegisterClass;
 
 class SSARegMap {
   IndexedMap<const TargetRegisterClass*, VirtReg2IndexFunctor> RegClassMap;
+  IndexedMap<std::pair<unsigned, unsigned>, VirtReg2IndexFunctor> RegSubIdxMap;
   unsigned NextRegNum;
 
  public:
@@ -42,12 +43,30 @@ class SSARegMap {
     assert(RegClass && "Cannot create register without RegClass!");
     RegClassMap.grow(NextRegNum);
     RegClassMap[NextRegNum] = RegClass;
+    RegSubIdxMap.grow(NextRegNum);
+    RegSubIdxMap[NextRegNum] = std::make_pair(0,0);
     return NextRegNum++;
   }
 
   unsigned getLastVirtReg() const {
     return NextRegNum - 1;
   }
+
+  void setIsSubRegister(unsigned Reg, unsigned SuperReg, unsigned SubIdx) {
+    RegSubIdxMap[Reg] = std::make_pair(SuperReg, SubIdx);
+  }
+
+  bool isSubRegister(unsigned Reg) const {
+    return RegSubIdxMap[Reg].first != 0;
+  }
+
+  unsigned getSuperRegister(unsigned Reg) const {
+    return RegSubIdxMap[Reg].first;
+  }
+
+  unsigned getSubRegisterIndex(unsigned Reg) const {
+    return RegSubIdxMap[Reg].second;
+  }
 };
 
 } // End llvm namespace