[llvm] AArch64: Partially move setting of libcall names out of TargetLowering (PR #142985)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/142985

Move the parts that aren't dependent on the subtarget into
RuntimeLibcallInfo, which should contain the superset of all possible
runtime calls and be accurate outside of codegen.

>From 08249e32d39727778c2c10a47d6dc2ca607b7ec0 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 3 Jun 2025 02:45:03 +0200
Subject: [PATCH] AArch64: Partially move setting of libcall names out of
 TargetLowering

Move the parts that aren't dependent on the subtarget into
RuntimeLibcallInfo, which should contain the superset of all possible
runtime calls and be accurate outside of codegen.
---
 llvm/lib/IR/RuntimeLibcalls.cpp               | 22 +++++++++++++++++++
 .../Target/AArch64/AArch64ISelLowering.cpp    | 12 ----------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/llvm/lib/IR/RuntimeLibcalls.cpp b/llvm/lib/IR/RuntimeLibcalls.cpp
index ca45cd4b7b13c..6ffe535242edd 100644
--- a/llvm/lib/IR/RuntimeLibcalls.cpp
+++ b/llvm/lib/IR/RuntimeLibcalls.cpp
@@ -11,6 +11,25 @@
 using namespace llvm;
 using namespace RTLIB;
 
+static cl::opt<bool>
+    HexagonEnableFastMathRuntimeCalls("hexagon-fast-math", cl::Hidden,
+                                      cl::desc("Enable Fast Math processing"));
+
+static void setAArch64LibcallNames(RuntimeLibcallsInfo &Info,
+                                   const Triple &TT) {
+  if (TT.isWindowsArm64EC()) {
+    // FIXME: are there calls we need to exclude from this?
+#define HANDLE_LIBCALL(code, name)                                             \
+  {                                                                            \
+    const char *libcallName = Info.getLibcallName(RTLIB::code);                \
+    if (libcallName && libcallName[0] != '#')                                  \
+      Info.setLibcallName(RTLIB::code, "#" #name);                             \
+  }
+#include "llvm/IR/RuntimeLibcalls.def"
+#undef HANDLE_LIBCALL
+  }
+}
+
 /// Set default libcall names. If a target wants to opt-out of a libcall it
 /// should be placed here.
 void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
@@ -249,6 +268,9 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
     }
   }
 
+  if (TT.getArch() == Triple::ArchType::aarch64)
+    setAArch64LibcallNames(*this, TT);
+
   if (TT.getArch() == Triple::ArchType::avr) {
     // Division rtlib functions (not supported), use divmod functions instead
     setLibcallName(RTLIB::SDIV_I8, nullptr);
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 9f51caef6d228..2019c9df0f271 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -1982,18 +1982,6 @@ AArch64TargetLowering::AArch64TargetLowering(const TargetMachine &TM,
   for (ISD::NodeType Op : {ISD::FLDEXP, ISD::STRICT_FLDEXP, ISD::FFREXP})
     if (isOperationExpand(Op, MVT::f16))
       setOperationAction(Op, MVT::f16, Promote);
-
-  if (Subtarget->isWindowsArm64EC()) {
-    // FIXME: are there calls we need to exclude from this?
-#define HANDLE_LIBCALL(code, name)                                             \
-  {                                                                            \
-    const char *libcallName = getLibcallName(RTLIB::code);                     \
-    if (libcallName && libcallName[0] != '#')                                  \
-      setLibcallName(RTLIB::code, "#" #name);                                  \
-  }
-#include "llvm/IR/RuntimeLibcalls.def"
-#undef HANDLE_LIBCALL
-  }
 }
 
 void AArch64TargetLowering::addTypeForNEON(MVT VT) {