[llvm] ISel/RISCV: restrict custom lowering of ISD::LRINT, ISD::LLRINT (PR #70926)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon created https://github.com/llvm/llvm-project/pull/70926

To follow up on 7a76038 (CodeGen/RISCV: increase test coverage of lrint, llrint), it is clear that the custom lowering of ISD::LRINT always works for i32, and only works for i64 if the subtarget is 64-bit. ISD::LLRINT custom-lowering works for i32 and i64. Hence, guard the appropriate setOperationAction() calls with these checks.

>From 7ef1d3e57d8935b6c32d52fc659cc9eae969e581 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <Ramkumar.Ramachandra at imgtec.com>
Date: Wed, 1 Nov 2023 11:53:18 +0000
Subject: [PATCH] ISel/RISCV: restrict custom lowering of ISD::LRINT,
 ISD::LLRINT

To follow up on 7a76038 (CodeGen/RISCV: increase test coverage of lrint,
llrint), it is clear that the custom lowering of ISD::LRINT always works
for i32, and only works for i64 if the subtarget is 64-bit. ISD::LLRINT
custom-lowering works for i32 and i64. Hence, guard the appropriate
setOperationAction() calls with these checks.
---
 llvm/lib/Target/RISCV/RISCVISelLowering.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index e9f80432ab190c7..479937f83cffa84 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -731,7 +731,12 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
                          VT, Custom);
       setOperationAction({ISD::FP_TO_SINT_SAT, ISD::FP_TO_UINT_SAT}, VT,
                          Custom);
-      setOperationAction({ISD::LRINT, ISD::LLRINT}, VT, Custom);
+      if (VT.getVectorElementType() == MVT::i32 ||
+          (VT.getVectorElementType() == MVT::i64 && Subtarget.is64Bit()))
+        setOperationAction({ISD::LRINT}, VT, Custom);
+      if (VT.getVectorElementType() == MVT::i64 ||
+          VT.getVectorElementType() == MVT::i32)
+        setOperationAction({ISD::LLRINT}, VT, Custom);
       setOperationAction(
           {ISD::SADDSAT, ISD::UADDSAT, ISD::SSUBSAT, ISD::USUBSAT}, VT, Legal);