[llvm] RISCV: Start moving runtime libcall config to tablegen (PR #147652)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/147652

>From c9c599f1894bf8f593a3d9004835857c73957582 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Wed, 9 Jul 2025 14:11:25 +0900
Subject: [PATCH] RISCV: Start moving runtime libcall config to tablegen

This doesn't yet attempt to move the OS dependent configuration
shared with other targets. Removes __riscv_flush_icache from the
default set so it's no longer falsely reported as available for
other targets.
---
 llvm/include/llvm/IR/RuntimeLibcalls.td | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index ebea7ec533c32..9a8dd66b7a1ad 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -696,7 +696,6 @@ def __llvm_deoptimize : RuntimeLibcallImpl<DEOPTIMIZE>;
 
 // Clear cache
 def __clear_cache : RuntimeLibcallImpl<CLEAR_CACHE>;
-def __riscv_flush_icache : RuntimeLibcallImpl<RISCV_FLUSH_ICACHE>;
 
 //--------------------------------------------------------------------
 // libm
@@ -956,6 +955,8 @@ def bzero : RuntimeLibcallImpl<BZERO>;
 def __bzero : RuntimeLibcallImpl<BZERO>;
 def _Unwind_SjLj_Resume : RuntimeLibcallImpl<UNWIND_RESUME>;
 
+def __riscv_flush_icache : RuntimeLibcallImpl<RISCV_FLUSH_ICACHE>;
+
 //===----------------------------------------------------------------------===//
 // F128 libm Runtime Libcalls
 //===----------------------------------------------------------------------===//
@@ -1903,6 +1904,18 @@ def PPCSystemLibrary
            AvailableIf<memcpy, isNotAIX>,
            LibcallImpls<(add Int128RTLibcalls), isPPC64>)>;
 
+//===----------------------------------------------------------------------===//
+// RISCV Runtime Libcalls
+//===----------------------------------------------------------------------===//
+
+def isRISCV : RuntimeLibcallPredicate<"TT.isRISCV()">;
+def isRISCV64 : RuntimeLibcallPredicate<"TT.isRISCV64()">;
+
+def RISCVSystemLibrary
+    : SystemRuntimeLibrary<isRISCV,
+      (add DefaultRuntimeLibcallImpls, __riscv_flush_icache,
+           LibcallImpls<(add Int128RTLibcalls), isRISCV64>)>;
+
 //===----------------------------------------------------------------------===//
 // SPARC Runtime Libcalls
 //===----------------------------------------------------------------------===//