[llvm] [TableGen] Strengthen check for what operands can be an immediate in CompressInstEmitter. (PR #150568)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/150568

Registers can be represented by RegisterOperand, not just RegisterClass. Instead of trying to block certain classes, only allow Operand.

>From ec88686f798900cb154214e166daaa1c997853d8 Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Thu, 24 Jul 2025 18:46:05 -0700
Subject: [PATCH] [TableGen] Strengthen check for what operands can be an
 immediate in CompressInstEmitter.

Registers can be represented by RegisterOperand, not just
RegisterClass. Instead of trying to block certain classes, only
allow Operand.
---
 llvm/utils/TableGen/CompressInstEmitter.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/utils/TableGen/CompressInstEmitter.cpp b/llvm/utils/TableGen/CompressInstEmitter.cpp
index 4665a964bd9e7..b2429664783b9 100644
--- a/llvm/utils/TableGen/CompressInstEmitter.cpp
+++ b/llvm/utils/TableGen/CompressInstEmitter.cpp
@@ -269,7 +269,7 @@ void CompressInstEmitter::addDagOperandMapping(const Record *Rec,
         OperandMap[OpNo].Kind = OpData::Operand;
       } else if (const auto *II = dyn_cast<IntInit>(Dag->getArg(DAGOpNo))) {
         // Validate that corresponding instruction operand expects an immediate.
-        if (OpndRec->isSubClassOf("RegisterClass"))
+        if (!OpndRec->isSubClassOf("Operand"))
           PrintFatalError(Rec->getLoc(), "Error in Dag '" + Dag->getAsString() +
                                              "' Found immediate: '" +
                                              II->getAsString() +