[llvm] 236b315 - [RISCV] Remove extra operands from Zcb compression patterns. NFC (#150541)

[via llvm-commits]

Author: Craig Topper
Date: 2025-07-24T18:03:30-07:00
New Revision: 236b315a98900468cc749a618e2204c0d499876a

URL: https://github.com/llvm/llvm-project/commit/236b315a98900468cc749a618e2204c0d499876a
DIFF: https://github.com/llvm/llvm-project/commit/236b315a98900468cc749a618e2204c0d499876a.diff

LOG: [RISCV] Remove extra operands from Zcb compression patterns. NFC (#150541)

Tied operands in the destination are not supposed to be listed. This
didn't cause a functional issue because none of the code noticed that
extra operand was even there.

Simplify verifyDagOpCount to catch this case.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
    llvm/utils/TableGen/CompressInstEmitter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td b/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
index f1734405fae63..ed1a60aa49cab 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoZc.td
@@ -291,31 +291,31 @@ def : CompressPat<(MUL GPRC:$rs1, GPRC:$rs2, GPRC:$rs1),
 
 let Predicates = [HasStdExtZcb, HasStdExtZbb] in{
 def : CompressPat<(SEXT_B GPRC:$rs1, GPRC:$rs1),
-                  (C_SEXT_B GPRC:$rs1, GPRC:$rs1)>;
+                  (C_SEXT_B GPRC:$rs1)>;
 def : CompressPat<(SEXT_H GPRC:$rs1, GPRC:$rs1),
-                  (C_SEXT_H GPRC:$rs1, GPRC:$rs1)>;
+                  (C_SEXT_H GPRC:$rs1)>;
 } // Predicates = [HasStdExtZcb, HasStdExtZbb]
 
 let Predicates = [HasStdExtZcb, HasStdExtZbb] in{
 def : CompressPat<(ZEXT_H_RV32 GPRC:$rs1, GPRC:$rs1),
-                  (C_ZEXT_H GPRC:$rs1, GPRC:$rs1)>;
+                  (C_ZEXT_H GPRC:$rs1)>;
 def : CompressPat<(ZEXT_H_RV64 GPRC:$rs1, GPRC:$rs1),
-                  (C_ZEXT_H GPRC:$rs1, GPRC:$rs1)>;
+                  (C_ZEXT_H GPRC:$rs1)>;
 } // Predicates = [HasStdExtZcb, HasStdExtZbb]
 
 let Predicates = [HasStdExtZcb] in{
 def : CompressPat<(ANDI GPRC:$rs1, GPRC:$rs1, 255),
-                  (C_ZEXT_B GPRC:$rs1, GPRC:$rs1)>;
+                  (C_ZEXT_B GPRC:$rs1)>;
 } // Predicates = [HasStdExtZcb]
 
 let Predicates = [HasStdExtZcb, HasStdExtZba, IsRV64] in{
 def : CompressPat<(ADD_UW GPRC:$rs1, GPRC:$rs1, X0),
-                  (C_ZEXT_W GPRC:$rs1, GPRC:$rs1)>;
+                  (C_ZEXT_W GPRC:$rs1)>;
 } // Predicates = [HasStdExtZcb, HasStdExtZba, IsRV64]
 
 let Predicates = [HasStdExtZcb] in{
 def : CompressPat<(XORI GPRC:$rs1, GPRC:$rs1, -1),
-                  (C_NOT GPRC:$rs1, GPRC:$rs1)>;
+                  (C_NOT GPRC:$rs1)>;
 }
 
 let Predicates = [HasStdExtZcb] in{

diff  --git a/llvm/utils/TableGen/CompressInstEmitter.cpp b/llvm/utils/TableGen/CompressInstEmitter.cpp
index afc892b068582..4665a964bd9e7 100644
--- a/llvm/utils/TableGen/CompressInstEmitter.cpp
+++ b/llvm/utils/TableGen/CompressInstEmitter.cpp
@@ -326,9 +326,6 @@ static bool verifyDagOpCount(const CodeGenInstruction &Inst, const DagInit *Dag,
       TiedOpCount++;
   }
 
-  if (Dag->getNumArgs() == NumMIOperands)
-    return true;
-
   // Source instructions are non compressed instructions and have at most one
   // tied operand.
   if (IsSource && (TiedOpCount > 1))
@@ -336,12 +333,6 @@ static bool verifyDagOpCount(const CodeGenInstruction &Inst, const DagInit *Dag,
                     "Input operands for Inst '" + Inst.TheDef->getName() +
                         "' and input Dag operand count mismatch");
 
-  // The Dag can't have more arguments than the Instruction.
-  if (Dag->getNumArgs() > NumMIOperands)
-    PrintFatalError(Inst.TheDef->getLoc(),
-                    "Inst '" + Inst.TheDef->getName() +
-                        "' and Dag operand count mismatch");
-
   // The Instruction might have tied operands so the Dag might have
   // a fewer operand count.
   if (Dag->getNumArgs() != (NumMIOperands - TiedOpCount))