Convert EXTRACT_SUBREG to COPY when emitting machine instrs.

EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107879 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegRewriter.cpp b/lib/CodeGen/VirtRegRewriter.cpp
index 11bd3cd..15142c0 100644
--- a/lib/CodeGen/VirtRegRewriter.cpp
+++ b/lib/CodeGen/VirtRegRewriter.cpp
@@ -2012,7 +2012,7 @@
       //       = EXTRACT_SUBREG fi#1
       // fi#1 is available in EDI, but it cannot be reused because it's not in
       // the right register file.
-      if (PhysReg && !AvoidReload && (SubIdx || MI.isExtractSubreg())) {
+      if (PhysReg && !AvoidReload && SubIdx) {
         const TargetRegisterClass* RC = MRI->getRegClass(VirtReg);
         if (!RC->contains(PhysReg))
           PhysReg = 0;