[llvm-branch-commits] [llvm] ARM: Move half convert libcall config to tablegen (PR #153389)

[Matt Arsenault via llvm-branch-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/153389

>From 377c2923243eab80d39bdb249aa5ed5c60f148cb Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 5 Aug 2025 19:46:09 +0900
Subject: [PATCH] ARM: Move half convert libcall config to tablegen

---
 llvm/include/llvm/IR/RuntimeLibcalls.td | 21 ++++++++++++++++++---
 llvm/lib/Target/ARM/ARMISelLowering.cpp | 22 ----------------------
 2 files changed, 18 insertions(+), 25 deletions(-)

diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index 736b439748c12..b6664fb2ba908 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -1280,6 +1280,9 @@ def AMDGPUSystemLibrary : SystemRuntimeLibrary<isAMDGPU, (add)>;
 // ARM Runtime Libcalls
 //===----------------------------------------------------------------------===//
 
+def isTargetAEABIAndAAPCS_ABI : RuntimeLibcallPredicate<
+  [{TT.isTargetAEABI() && isAAPCS_ABI(TT, ABIName)}]>;
+
 // if (isTargetMachO()) {
 // if (Subtarget->isThumb() && Subtarget->hasVFP2Base() &&
 //  Subtarget->hasARMOps() && !Subtarget->useSoftFloat()) {
@@ -1473,13 +1476,23 @@ def __udivmodsi4 : RuntimeLibcallImpl<UDIVREM_I32>;
 // a __gnu_ prefix (which is the default).
 // isTargetAEABI()
 def __aeabi_f2h : RuntimeLibcallImpl<FPROUND_F32_F16>; // CallingConv::ARM_AAPCS
-//def __aeabi_d2h : RuntimeLibcallImpl<FPROUND_F64_F16>; // CallingConv::ARM_AAPCS
 def __aeabi_h2f : RuntimeLibcallImpl<FPEXT_F16_F32>; // CallingConv::ARM_AAPCS
 
 // !isTargetMachO()
 def __gnu_f2h_ieee : RuntimeLibcallImpl<FPROUND_F32_F16>;
 def __gnu_h2f_ieee : RuntimeLibcallImpl<FPEXT_F16_F32>;
 
+def GNUEABIHalfConvertCalls :
+  LibcallImpls<(add __gnu_f2h_ieee, __gnu_h2f_ieee),
+    RuntimeLibcallPredicate<[{!TT.isOSBinFormatMachO() &&
+                              !TT.isTargetAEABI()}]>>;
+
+// In EABI, these functions have an __aeabi_ prefix, but in GNUEABI
+// they have a __gnu_ prefix (which is the default).
+def EABIHalfConvertCalls : LibcallImpls<(add __aeabi_f2h, __aeabi_h2f),
+                                        isTargetAEABIAndAAPCS_ABI> {
+  let CallingConv = ARM_AAPCS;
+}
 
 def WindowARMDivRemCalls : LibcallImpls<
   (add __rt_sdiv, __rt_sdiv64, __rt_udiv, __rt_udiv64),
@@ -1553,8 +1566,8 @@ def AEABICalls : LibcallImpls<
       // RTABI chapter 4.1.2, Table 7
       __aeabi_d2f,
       __aeabi_f2d,
-      __aeabi_h2f,
-      __aeabi_f2h,
+      //__aeabi_h2f added separately
+      //__aeabi_f2h added separately
       __aeabi_d2h,
 
       // Integer to floating-point conversions.
@@ -1614,6 +1627,8 @@ def ARMSystemLibrary
 
            AEABICalls,
            AEABI45MemCalls,
+           EABIHalfConvertCalls,
+           GNUEABIHalfConvertCalls,
 
            // Use divmod compiler-rt calls for iOS 5.0 and later.
            LibcallImpls<(add __divmodsi4, __udivmodsi4),
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index bd246943f63fc..8ea567cfb9d31 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -587,28 +587,6 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     }
   }
 
-  // In EABI, these functions have an __aeabi_ prefix, but in GNUEABI they have
-  // a __gnu_ prefix (which is the default).
-  if (TT.isTargetAEABI()) {
-    // FIXME: This does not depend on the subtarget and should go directly into
-    // RuntimeLibcalls. This is only here because of missing support for setting
-    // the calling convention of an implementation.
-    static const struct {
-      const RTLIB::Libcall Op;
-      const RTLIB::LibcallImpl Impl;
-    } LibraryCalls[] = {
-        {RTLIB::FPROUND_F32_F16, RTLIB::__aeabi_f2h},
-        {RTLIB::FPEXT_F16_F32, RTLIB::__aeabi_h2f},
-    };
-
-    for (const auto &LC : LibraryCalls) {
-      setLibcallImpl(LC.Op, LC.Impl);
-    }
-  } else if (!TT.isOSBinFormatMachO()) {
-    setLibcallImpl(RTLIB::FPROUND_F32_F16, RTLIB::__gnu_f2h_ieee);
-    setLibcallImpl(RTLIB::FPEXT_F16_F32, RTLIB::__gnu_h2f_ieee);
-  }
-
   if (Subtarget->isThumb1Only())
     addRegisterClass(MVT::i32, &ARM::tGPRRegClass);
   else