[X86] cleanup inline asm register generation. NFCI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354042 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 680aa43..0ecead8 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -43209,20 +43209,20 @@
       if (Size == 64 && !is64Bit) {
         // Model GCC's behavior here and select a fixed pair of 32-bit
         // registers.
-        switch (Res.first) {
-        case X86::EAX:
+        switch (DestReg) {
+        case X86::RAX:
           return std::make_pair(X86::EAX, &X86::GR32_ADRegClass);
-        case X86::EDX:
+        case X86::RDX:
           return std::make_pair(X86::EDX, &X86::GR32_DCRegClass);
-        case X86::ECX:
+        case X86::RCX:
           return std::make_pair(X86::ECX, &X86::GR32_CBRegClass);
-        case X86::EBX:
+        case X86::RBX:
           return std::make_pair(X86::EBX, &X86::GR32_BSIRegClass);
-        case X86::ESI:
+        case X86::RSI:
           return std::make_pair(X86::ESI, &X86::GR32_SIDIRegClass);
-        case X86::EDI:
+        case X86::RDI:
           return std::make_pair(X86::EDI, &X86::GR32_DIBPRegClass);
-        case X86::EBP:
+        case X86::RBP:
           return std::make_pair(X86::EBP, &X86::GR32_BPSPRegClass);
         default:
           return std::make_pair(0, nullptr);