[llvm-branch-commits] [llvm] RuntimeLibcalls: Remove the Default* libcall lists (PR #230405)

[Matt Arsenault via llvm-branch-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/230405

Every system library now lists only LibcallLibrary members, so nothing
references DefaultRuntimeLibcallImpls. arm64ec's '#'-prefixed set was
still derived from the whole default list minus the width slices and
the Windows exclusions. Build it from the compiler-rt, libm and libc
slices instead, still omitting the calls the Windows runtime lacks.
Take AArch64's fp128 long double calls from the libm slice, and delete
the remaining default and Windows base lists.

The generated tables are unchanged.

Co-authored-by: Claude Opus 5.5 <noreply at anthropic.com>

>From e823d2c66f32df776329e572a2eb847d1a1f5780 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Fri, 9 Oct 2026 10:07:04 +0200
Subject: [PATCH] RuntimeLibcalls: Remove the Default* libcall lists

Every system library now lists only LibcallLibrary members, so nothing
references DefaultRuntimeLibcallImpls. arm64ec's '#'-prefixed set was
still derived from the whole default list minus the width slices and
the Windows exclusions. Build it from the compiler-rt, libm and libc
slices instead, still omitting the calls the Windows runtime lacks.
Take AArch64's fp128 long double calls from the libm slice, and delete
the remaining default and Windows base lists.

The generated tables are unchanged.

Co-authored-by: Claude Opus 5.5 <noreply at anthropic.com>
---
 llvm/include/llvm/IR/RuntimeLibcalls.td | 75 +++----------------------
 1 file changed, 9 insertions(+), 66 deletions(-)

diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index f5a2c31407ee8..59460986a2c88 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -2030,38 +2030,6 @@ defvar ExceptionModelCalls = (add
 // module's exception model.
 def ExceptionRuntime : LibcallLibrary<"unwind", ExceptionModelCalls>;
 
-// FIXME: Should move to explicit opt-in to different sets of libcalls
-// instead of trying to remove from a default set. We have
-// unreasonable defaults like reporting f80 calls on most targets when
-// they are relevant to only one.
-
-defvar AllDefaultRuntimeLibcallImpls
-  = !listconcat(CompilerRtLibgccImpls, LibmCoreImpls, LibcCoreImpls);
-
-defvar DefaultRuntimeLibcallImpls_f80 =
-    !filter(entry, AllDefaultRuntimeLibcallImpls,
-            !match(!cast<string>(entry.Provides), "F80"));
-
-// The l-suffixed libm math functions, only correct when long double is x87.
-defvar DefaultRuntimeLibcallImpls_longdouble_f80 =
-    !filter(entry, AllDefaultRuntimeLibcallImpls,
-            !match(!cast<string>(entry), "l_f80"));
-
-// The compiler-rt helpers, keyed to the x86_fp80 IR type and available on all
-// x86 regardless of the long double format.
-defvar DefaultRuntimeLibcallImpls_f80_helpers =
-    !listremove(DefaultRuntimeLibcallImpls_f80,
-                DefaultRuntimeLibcallImpls_longdouble_f80);
-
-defvar DefaultRuntimeLibcallImpls_ppcf128 =
-    !filter(entry, AllDefaultRuntimeLibcallImpls,
-            !match(!cast<string>(entry.Provides), "PPCF128"));
-
-// The l-suffixed libm functions are fp128 only when long double is fp128.
-defvar DefaultRuntimeLibcallImpls_longdouble_f128 =
-    !filter(entry, AllDefaultRuntimeLibcallImpls,
-            !match(!cast<string>(entry), "l_f128"));
-
 // Width-specific slices of the compiler-rt/libgcc body. The core keeps the
 // integer, f32, f64 and f128 helpers; the f80 and ppcf128 slices are added
 // separately.
@@ -2078,24 +2046,6 @@ defvar CompilerRtLibgccImpls_core =
       !listremove(CompilerRtLibgccImpls, CompilerRtLibgccImpls_f80),
                   CompilerRtLibgccImpls_ppcf128);
 
-// FIXME: Ideally we would just use dags everywhere, but for the
-// arm64ec case we need iterable lists so we can add the # prefix
-//
-// The fp128 long double libcalls are added on a per-target basis.
-defvar DefaultRuntimeLibcallImplsBaseList =
-!listremove(
-  !listremove(
-    !listremove(
-      !listremove(AllDefaultRuntimeLibcallImpls, Int128RTLibcalls),
-                  DefaultRuntimeLibcallImpls_f80),
-                  DefaultRuntimeLibcallImpls_ppcf128),
-                  DefaultRuntimeLibcallImpls_longdouble_f128);
-
-defvar DefaultRuntimeLibcallImpls =
-  (add DefaultRuntimeLibcallImplsBaseList,
-       LibcallImpls<(add DefaultRuntimeLibcallImpls_longdouble_f128),
-                    isLongDoubleF128>,
-       ExceptionModelCalls);
 
 // TODO: Guessing sincospi added at same time as sincos_stret
 defvar DarwinSinCosStret = LibcallImpls<(add __sincosf_stret, __sincos_stret,
@@ -2138,20 +2088,6 @@ defvar LibmHasExp10F128 = LibcallImpls<(add exp10l_f128), hasExp10>;
 defvar LibmHasFrexpF32 = LibcallImpls<(add frexpf), isNotOSWindowsOrIsCygwinMinGW>;
 defvar LibmHasLdexpF32 = LibcallImpls<(add ldexpf), isNotOSWindowsOrIsCygwinMinGW>;
 
-defvar WindowsMathRemovals = [
-  ldexpf, ldexpl_f80, ldexpl_f128, ldexpl_ppcf128,
-  frexpf, frexpl_f80, frexpl_f128, frexpl_ppcf128
-];
-
-defvar MostPowI = !listremove(PowiLibcallImpls, [__powitf2_f128, __powitf2_ppc128]);
-defvar WindowsExclusions = !listconcat(WindowsMathRemovals, MostPowI);
-
-// Targets which support windows start with this as a base and add in calls for
-// other OSes.
-defvar WinDefaultLibcallImplsBaseList =
-  !listremove(DefaultRuntimeLibcallImplsBaseList,
-              WindowsExclusions);
-
 defvar LibmHasFrexpF128 = LibcallImpls<(add frexpl_f128), isNotOSWindowsOrIsCygwinMinGW>;
 defvar LibmHasLdexpF128 = LibcallImpls<(add ldexpl_f128), isNotOSWindowsOrIsCygwinMinGW>;
 
@@ -2405,7 +2341,7 @@ def isAArch64_ILP64
 
 // frexpl/ldexpl/exp10l are added separately based on the Target Triple.
 defvar AArch64LongDoubleF128Body =
-    !listremove(DefaultRuntimeLibcallImpls_longdouble_f128,
+    !listremove(LibmCoreImpls_f128,
                 [frexpl_f128, ldexpl_f128, exp10l_f128]);
 
 // AArch64 libm extras.
@@ -2431,9 +2367,16 @@ def AArch64SystemLibrary : SystemRuntimeLibrary<
        AArch64SMERuntime, SafeStackRuntime)
 >;
 
+// The Windows runtime lacks the f32 and f64 powi helpers, and frexpf/ldexpf.
+defvar Arm64ECCompilerRtImpls =
+    !listremove(CompilerRtLibgccImpls_core,
+                !listremove(PowiLibcallImpls, [__powitf2_f128, __powitf2_ppc128]));
+defvar Arm64ECLibmImpls = !listremove(LibmCoreImpls_core, LibmFrexpLdexpF32);
+
 // Prepend a # to every name
 defset list<RuntimeLibcallImpl> WinArm64ECDefaultRuntimeLibcallImpls = {
-  foreach libcall = WinDefaultLibcallImplsBaseList in {
+  foreach libcall = !listconcat(Arm64ECCompilerRtImpls, Arm64ECLibmImpls,
+                                LibcCoreImpls) in {
     def arm64ec_#libcall : DuplicateLibcallImplWithPrefix<libcall, "#">;
   }