[RISCV] Move vendor extensions after standard extensions in RISCVDisassembler::getInstruction16.

All of the vendor extensions should be mutex with the standard
extensions based on the incompatible extension checks in
RISCVISAInfo.cpp. There is one missing check that will be fixed by

I'll make a similar patch for the 32-bit table, but I need to do
more auditing first.

Author: topperc

llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp

@@ -736,14 +736,7 @@ DecodeStatus RISCVDisassembler::getInstruction16(MCInst &MI, uint64_t &Size,
 
   uint32_t Insn = support::endian::read16le(Bytes.data());
 
-  TRY_TO_DECODE_FEATURE_ANY(XqciFeatureGroup, DecoderTableXqci16,
-                            "Qualcomm uC 16bit");
-  TRY_TO_DECODE_FEATURE(
-      RISCV::FeatureVendorXqccmp, DecoderTableXqccmp16,
-      "Xqccmp (Qualcomm 16-bit Push/Pop & Double Move Instructions)");
-  TRY_TO_DECODE_AND_ADD_SP(STI.hasFeature(RISCV::FeatureVendorXwchc),
-                           DecoderTableXwchc16, "WCH QingKe XW");
-
+  // Standard Extensions
   // DecoderTableZicfiss16 must be checked before DecoderTable16.
   TRY_TO_DECODE(true, DecoderTableZicfiss16, "RVZicfiss (Shadow Stack)");
   TRY_TO_DECODE_AND_ADD_SP(true, DecoderTable16,
@@ -754,6 +747,15 @@ DecodeStatus RISCVDisassembler::getInstruction16(MCInst &MI, uint64_t &Size,
   TRY_TO_DECODE(true, DecoderTableZcOverlap16,
                 "ZcOverlap (16-bit Instructions overlapping with Zcf/Zcd)");
 
+  // Vendor Extensions
+  TRY_TO_DECODE_FEATURE_ANY(XqciFeatureGroup, DecoderTableXqci16,
+                            "Qualcomm uC 16bit");
+  TRY_TO_DECODE_FEATURE(
+      RISCV::FeatureVendorXqccmp, DecoderTableXqccmp16,
+      "Xqccmp (Qualcomm 16-bit Push/Pop & Double Move Instructions)");
+  TRY_TO_DECODE_AND_ADD_SP(STI.hasFeature(RISCV::FeatureVendorXwchc),
+                           DecoderTableXwchc16, "WCH QingKe XW");
+
   return MCDisassembler::Fail;
 }