[X86] Add isel patterns for commuting X86adc_flag with a load in the LHS.

The peephole pass likely gets this normally, but we should be doing it during isel.

Ideally we'd just make the X86adc_flag pattern SDNPCommutable, but the tablegen doesn't handle that when one of the operands is a register reference.

llvm-svn: 341596
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 1cca1f1..0773acc 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -522,7 +522,9 @@
     switch (U->getOpcode()) {
     default: break;
     case X86ISD::ADD:
+    case X86ISD::ADC:
     case X86ISD::SUB:
+    case X86ISD::SBB:
     case X86ISD::AND:
     case X86ISD::XOR:
     case X86ISD::OR: