[llvm] RuntimeLibcalls: Invert handling of 64-bit only libcalls (PR #148571)
Matt Arsenault via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 14 08:56:25 PDT 2025
https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/148571
>From 26b50d9fd547ce8657102c8f043dd261a07d3d1f Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 14 Jul 2025 14:53:08 +0900
Subject: [PATCH 1/2] RuntimeLibcalls: Invert handling of 64-bit only libcalls
Switch the default set to exclude these conditionally available
calls, so they are opt-in instead of opt-out.
---
llvm/include/llvm/IR/RuntimeLibcalls.td | 10 +++++-----
llvm/lib/IR/RuntimeLibcalls.cpp | 20 +++++++++++---------
2 files changed, 16 insertions(+), 14 deletions(-)
diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index 39cff4d32346f..42eaf40588960 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -439,26 +439,21 @@ let IsDefault = true in {
def __ashlhi3 : RuntimeLibcallImpl<SHL_I16>;
def __ashlsi3 : RuntimeLibcallImpl<SHL_I32>;
def __ashldi3 : RuntimeLibcallImpl<SHL_I64>;
-def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
def __lshrhi3 : RuntimeLibcallImpl<SRL_I16>;
def __lshrsi3 : RuntimeLibcallImpl<SRL_I32>;
def __lshrdi3 : RuntimeLibcallImpl<SRL_I64>;
-def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
def __ashrhi3 : RuntimeLibcallImpl<SRA_I16>;
def __ashrsi3 : RuntimeLibcallImpl<SRA_I32>;
def __ashrdi3 : RuntimeLibcallImpl<SRA_I64>;
-def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
def __mulqi3 : RuntimeLibcallImpl<MUL_I8>;
def __mulhi3 : RuntimeLibcallImpl<MUL_I16>;
def __mulsi3 : RuntimeLibcallImpl<MUL_I32>;
def __muldi3 : RuntimeLibcallImpl<MUL_I64>;
-def __multi3 : RuntimeLibcallImpl<MUL_I128>;
def __mulosi4 : RuntimeLibcallImpl<MULO_I32>;
-def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
def __divqi3 : RuntimeLibcallImpl<SDIV_I8>;
def __divhi3 : RuntimeLibcallImpl<SDIV_I16>;
@@ -938,6 +933,11 @@ def calloc : RuntimeLibcallImpl<CALLOC>;
// compiler-rt, not available for most architectures
//--------------------------------------------------------------------
+def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
+def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
+def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
+def __multi3 : RuntimeLibcallImpl<MUL_I128>;
+def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
def __muloti4 : RuntimeLibcallImpl<MULO_I128>;
//--------------------------------------------------------------------
diff --git a/llvm/lib/IR/RuntimeLibcalls.cpp b/llvm/lib/IR/RuntimeLibcalls.cpp
index 3dd894ad6c50e..74cde5e9cee92 100644
--- a/llvm/lib/IR/RuntimeLibcalls.cpp
+++ b/llvm/lib/IR/RuntimeLibcalls.cpp
@@ -139,6 +139,10 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
EABI EABIVersion, StringRef ABIName) {
setTargetRuntimeLibcallSets(TT, FloatABI);
+ // Early exit for targets that have fully ported to tablegen.
+ if (TT.isAMDGPU() || TT.isNVPTX() || TT.isWasm())
+ return;
+
// Use the f128 variants of math functions on x86
if (TT.isX86() && TT.isGNUEnvironment())
setLongDoubleIsF128Libm(*this, /*FiniteOnlyFuncs=*/true);
@@ -241,15 +245,13 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT,
if (TT.isARM() || TT.isThumb())
setARMLibcallNames(*this, TT, FloatABI, EABIVersion);
- if (!TT.isWasm()) {
- // These libcalls are only available in compiler-rt, not libgcc.
- if (TT.isArch32Bit()) {
- setLibcallImpl(RTLIB::SHL_I128, RTLIB::Unsupported);
- setLibcallImpl(RTLIB::SRL_I128, RTLIB::Unsupported);
- setLibcallImpl(RTLIB::SRA_I128, RTLIB::Unsupported);
- setLibcallImpl(RTLIB::MUL_I128, RTLIB::Unsupported);
- setLibcallImpl(RTLIB::MULO_I64, RTLIB::Unsupported);
- }
+ // These libcalls are only available in compiler-rt, not libgcc.
+ if (TT.isArch64Bit()) {
+ setLibcallImpl(RTLIB::SHL_I128, RTLIB::__ashlti3);
+ setLibcallImpl(RTLIB::SRL_I128, RTLIB::__lshrti3);
+ setLibcallImpl(RTLIB::SRA_I128, RTLIB::__ashrti3);
+ setLibcallImpl(RTLIB::MUL_I128, RTLIB::__multi3);
+ setLibcallImpl(RTLIB::MULO_I64, RTLIB::__mulodi4);
}
if (TT.getArch() == Triple::ArchType::msp430) {
>From b1cc3188f7872ea1598b7a8859c1a646c837c51f Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 14 Jul 2025 18:28:51 +0900
Subject: [PATCH 2/2] Tidy categories
---
llvm/include/llvm/IR/RuntimeLibcalls.td | 52 ++++++++++++-------------
1 file changed, 24 insertions(+), 28 deletions(-)
diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index 42eaf40588960..ff343f30f0325 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -930,15 +930,29 @@ def calloc : RuntimeLibcallImpl<CALLOC>;
} // End let IsDefault = true
//--------------------------------------------------------------------
-// compiler-rt, not available for most architectures
+// compiler-rt/libgcc but 64-bit only, not available by default
//--------------------------------------------------------------------
-def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
-def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
-def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
-def __multi3 : RuntimeLibcallImpl<MUL_I128>;
-def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
-def __muloti4 : RuntimeLibcallImpl<MULO_I128>;
+// Exist in libgcc and compiler-rt for 64-bit targets, or if
+// COMPILER_RT_ENABLE_SOFTWARE_INT128.
+defset list<RuntimeLibcallImpl> Int128RTLibcalls = {
+ def __ashlti3 : RuntimeLibcallImpl<SHL_I128>;
+ def __lshrti3 : RuntimeLibcallImpl<SRL_I128>;
+ def __ashrti3 : RuntimeLibcallImpl<SRA_I128>;
+ def __multi3 : RuntimeLibcallImpl<MUL_I128>;
+}
+
+//--------------------------------------------------------------------
+// compiler-rt only, not available by default
+//--------------------------------------------------------------------
+
+defset list<RuntimeLibcallImpl> CompilerRTOnlyInt64Libcalls = {
+ def __mulodi4 : RuntimeLibcallImpl<MULO_I64>;
+}
+
+defset list<RuntimeLibcallImpl> CompilerRTOnlyInt128Libcalls = {
+ def __muloti4 : RuntimeLibcallImpl<MULO_I128>;
+}
//--------------------------------------------------------------------
// Define implementation other libcalls
@@ -1034,21 +1048,6 @@ defset list<RuntimeLibcallImpl> LibmF128FiniteLibcalls = {
defvar AllDefaultRuntimeLibcallImpls
= !filter(entry, !instances<RuntimeLibcallImpl>(), entry.IsDefault);
-// Exist in libgcc and compiler-rt for 64-bit targets, or if
-// COMPILER_RT_ENABLE_SOFTWARE_INT128.
-defvar Int128RTLibcalls = [
- __ashlti3, __lshrti3, __ashrti3, __multi3
-];
-
-// Only available in compiler-rt
-defvar CompilerRTOnlyInt64Libcalls = [
- __mulodi4
-];
-
-defvar CompilerRTOnlyInt128Libcalls = [
- __muloti4
-];
-
defvar DefaultRuntimeLibcallImpls_f80 =
!filter(entry, AllDefaultRuntimeLibcallImpls,
!match(!cast<string>(entry.Provides), "F80"));
@@ -1064,12 +1063,9 @@ defvar DefaultRuntimeLibcallImpls_f128 =
defvar DefaultRuntimeLibcallImpls =
!listremove(
!listremove(
- !listremove(
- !listremove(AllDefaultRuntimeLibcallImpls, Int128RTLibcalls),
- !listconcat(CompilerRTOnlyInt64Libcalls,
- CompilerRTOnlyInt128Libcalls)),
- DefaultRuntimeLibcallImpls_f80),
- DefaultRuntimeLibcallImpls_ppcf128);
+ !listremove(AllDefaultRuntimeLibcallImpls, Int128RTLibcalls),
+ DefaultRuntimeLibcallImpls_f80),
+ DefaultRuntimeLibcallImpls_ppcf128);
/// Default set of libcall impls for 32-bit architectures.
defvar DefaultLibcallImpls32 = DefaultRuntimeLibcallImpls;
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