[llvm] [RISCV] Move vendor extensions after standard extensions in RISCVDisassembler::getInstruction16. (PR #130821)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/130821

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 #130816.

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

>From 9bcea86c1ef6170daf6821b4c82b658296d9a2e5 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Tue, 11 Mar 2025 12:41:50 -0700
Subject: [PATCH] [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.
---
 .../RISCV/Disassembler/RISCVDisassembler.cpp   | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp b/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
index de742ac428de2..857cca31b62cd 100644
--- a/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
+++ b/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;
 }