[llvm] [MC][TableGen] Expand ImplicitOffset field of MCInstrDesc (PR #138127)

[Carl Ritson via llvm-commits]

https://github.com/perlfu created https://github.com/llvm/llvm-project/pull/138127

Increase width of ImplicitOffset to `int` from `short` to allow more table capacity.
Reorder the elements to maintain natural alignment.

>From e675805e927eebdb2324cc85b49b90d6441159f9 Mon Sep 17 00:00:00 2001
From: Carl Ritson <carl.ritson at amd.com>
Date: Thu, 1 May 2025 20:59:53 +0900
Subject: [PATCH] [MC][TableGen] Expand ImplicitOffset field of MCInstrDesc

Increase width of ImplicitOffset to int from short to allow
more table capacity.
Reorder the elements to maintain natural alignment.
---
 llvm/include/llvm/MC/MCInstrDesc.h       | 2 +-
 llvm/utils/TableGen/InstrInfoEmitter.cpp | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/MC/MCInstrDesc.h b/llvm/include/llvm/MC/MCInstrDesc.h
index ef0b3c0a73992..5bb7f18bf2587 100644
--- a/llvm/include/llvm/MC/MCInstrDesc.h
+++ b/llvm/include/llvm/MC/MCInstrDesc.h
@@ -209,8 +209,8 @@ class MCInstrDesc {
   unsigned short SchedClass;     // enum identifying instr sched class
   unsigned char NumImplicitUses; // Num of regs implicitly used
   unsigned char NumImplicitDefs; // Num of regs implicitly defined
-  unsigned short ImplicitOffset; // Offset to start of implicit op list
   unsigned short OpInfoOffset;   // Offset to info about operands
+  unsigned int ImplicitOffset;   // Offset to start of implicit op list
   uint64_t Flags;                // Flags identifying machine instr class
   uint64_t TSFlags;              // Target Specific Flag values
 
diff --git a/llvm/utils/TableGen/InstrInfoEmitter.cpp b/llvm/utils/TableGen/InstrInfoEmitter.cpp
index 377bfb593be5f..f240cab040caa 100644
--- a/llvm/utils/TableGen/InstrInfoEmitter.cpp
+++ b/llvm/utils/TableGen/InstrInfoEmitter.cpp
@@ -1106,12 +1106,14 @@ void InstrInfoEmitter::emitRecord(
   OS << Inst.ImplicitUses.size() << ",\t" << Inst.ImplicitDefs.size() << ",\t";
   std::vector<const Record *> ImplicitOps = Inst.ImplicitUses;
   llvm::append_range(ImplicitOps, Inst.ImplicitDefs);
-  OS << Target.getName() << "ImpOpBase + " << EmittedLists[ImplicitOps]
-     << ",\t";
 
   // Emit the operand info offset.
   OperandInfoTy OperandInfo = GetOperandInfo(Inst);
-  OS << OperandInfoMap.find(OperandInfo)->second << ",\t0";
+  OS << OperandInfoMap.find(OperandInfo)->second << ",\t";
+
+  // Emit implicit operand base.
+  OS << Target.getName() << "ImpOpBase + " << EmittedLists[ImplicitOps]
+     << ",\t0";
 
   // Emit all of the target independent flags...
   if (Inst.isPreISelOpcode)