[llvm] r231111 - Add a comment above findRepresentativeClass explaining why it's

[Eric Christopher]

Author: echristo
Date: Tue Mar  3 13:47:14 2015
New Revision: 231111

URL: http://llvm.org/viewvc/llvm-project?rev=231111&view=rev
Log:
Add a comment above findRepresentativeClass explaining why it's
where it is so that future generations can understand.

Modified:
    llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp

Modified: llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp?rev=231111&r1=231110&r2=231111&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp Tue Mar  3 13:47:14 2015
@@ -1144,6 +1144,10 @@ TargetLoweringBase::emitPatchPoint(Machi
 
 /// findRepresentativeClass - Return the largest legal super-reg register class
 /// of the register class for the specified type and its associated "cost".
+// This function is in TargetLowering because it uses RegClassForVT which would
+// need to be moved to TargetRegisterInfo and would necessitate moving
+// isTypeLegal over as well - a massive change that would just require
+// TargetLowering having a TargetRegisterInfo class member that it would use.
 std::pair<const TargetRegisterClass *, uint8_t>
 TargetLoweringBase::findRepresentativeClass(const TargetRegisterInfo *TRI,
                                             MVT VT) const {