[TableGen] Fix invalid comparison function `SizeOrder` in `getMatchingSubClassWithSub...

Building LLVM with -DEXPENSIVE_CHECKS fails with the following error
message with libstdc++ in debug mode:

Error: comparison doesn't meet irreflexive requirements,
assert(!(a < a)).

The patch fixes the comparison function SizeOrder by returning false
when comparing two equal items.

diff --git a/llvm/utils/TableGen/CodeGenRegisters.cpp b/llvm/utils/TableGen/CodeGenRegisters.cpp
index eeb715d..18a2de1 100644 (file)
--- a/llvm/utils/TableGen/CodeGenRegisters.cpp
+++ b/llvm/utils/TableGen/CodeGenRegisters.cpp
@@ -999,6 +999,8 @@ CodeGenRegisterClass::getMatchingSubClassWithSubRegs(
                       const CodeGenRegisterClass *B) {
     // If there are multiple, identical register classes, prefer the original
     // register class.
+    if (A == B)
+      return false;
     if (A->getMembers().size() == B->getMembers().size())
       return A == this;
     return A->getMembers().size() > B->getMembers().size();