[llvm] [RISCV][NFC] Correct c_lui_imm (PR #135448)

[Sam Elliott via llvm-commits]

https://github.com/lenary created https://github.com/llvm/llvm-project/pull/135448

The MCOperandPredicate seems to allow symbols as well as immediates, but the parser/matcher does not due to `isCLUIImm`. This brings both in line with each other, and should prevent trying to compress a `lui` with a symbol, which cannot be emitted as a `c.lui` as there are no relocations for this as `R_RISCV_RVC_LUI` is deprecated/removed.

>From 489ebe3f61f88e87ccc9ff7c3975897abdfdeb12 Mon Sep 17 00:00:00 2001
From: Sam Elliott <quic_aelliott at quicinc.com>
Date: Fri, 11 Apr 2025 15:32:14 -0700
Subject: [PATCH] [RISCV][NFC] Correct c_lui_imm

The MCOperandPredicate seems to allow symbols as well as immediates, but
the parser/matcher does not due to `isCLUIImm`. This brings both in line
with each other, and should prevent trying to compress a `lui` with a
symbol, which cannot be emitted as a `c.lui` as there are no relocations
for this as `R_RISCV_RVC_LUI` is deprecated/removed.
---
 llvm/lib/Target/RISCV/RISCVInstrInfoC.td | 8 ++++----
 llvm/test/MC/RISCV/rv32c-invalid.s       | 1 +
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVInstrInfoC.td b/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
index fc036f6516116..252100c814f2b 100644
--- a/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
+++ b/llvm/lib/Target/RISCV/RISCVInstrInfoC.td
@@ -85,10 +85,10 @@ def c_lui_imm : RISCVOp,
   let OperandType = "OPERAND_CLUI_IMM";
   let MCOperandPredicate = [{
     int64_t Imm;
-    if (MCOp.evaluateAsConstantImm(Imm))
-      return (Imm != 0) && (isUInt<5>(Imm) ||
-             (Imm >= 0xfffe0 && Imm <= 0xfffff));
-    return MCOp.isBareSymbolRef();
+    if (!MCOp.evaluateAsConstantImm(Imm))
+      return false;
+    return (Imm != 0) && (isUInt<5>(Imm) ||
+           (Imm >= 0xfffe0 && Imm <= 0xfffff));
   }];
 }
 
diff --git a/llvm/test/MC/RISCV/rv32c-invalid.s b/llvm/test/MC/RISCV/rv32c-invalid.s
index 1027c08505d50..8dddbf887c87c 100644
--- a/llvm/test/MC/RISCV/rv32c-invalid.s
+++ b/llvm/test/MC/RISCV/rv32c-invalid.s
@@ -69,6 +69,7 @@ c.lui t0, 0 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xffff
 c.lui t0, 32 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 c.lui t0, 0xffffdf # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 c.lui t0, 0x1000000 # CHECK: :[[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
+c.lui t0, foo # CHECK: [[@LINE]]:11: error: immediate must be in [0xfffe0, 0xfffff] or [1, 31]
 
 ## uimm8_lsb00
 c.lwsp  ra, 256(sp) # CHECK: :[[@LINE]]:13: error: immediate must be a multiple of 4 bytes in the range [0, 252]