[IR] Change fp128 lowering to use f128 functions by default

LLVM currently emits calls to `*l` (`long double`) libm symbols for
`fp128` intrinsics. This works on platforms where `long double` and
`_Float128` are the same type, but is incorrect on many platforms.

Change RuntimeLibcalls such that `*f128` libcalls are used by default,
which is always safe and correct but may not be available. On platforms
where it is likely that `sqrtf128` and similar are not available, keep
the current behavior of lowering to `*l` symbols if `long double` is
`binary128`.

The logic for whether f128 is `long double` is based on the platforms in
Clang that set `LongDoubleFormat` to `llvm::APFloat::IEEEquad`.

Fixes llvm#44744

Author: tgross35

llvm/include/llvm/IR/RuntimeLibcalls.def

@@ -89,7 +89,8 @@ HANDLE_LIBCALL(CTPOP_I32, "__popcountsi2")
 HANDLE_LIBCALL(CTPOP_I64, "__popcountdi2")
 HANDLE_LIBCALL(CTPOP_I128, "__popcountti2")
 
-// Floating-point
+// Floating-point. Note that new fp128 math routines should also be added to
+// setF128LibcallFormat in RuntimeLibcalls.cpp.
 HANDLE_LIBCALL(ADD_F32, "__addsf3")
 HANDLE_LIBCALL(ADD_F64, "__adddf3")
 HANDLE_LIBCALL(ADD_F80, "__addxf3")
@@ -113,12 +114,12 @@ HANDLE_LIBCALL(DIV_PPCF128, "__gcc_qdiv")
 HANDLE_LIBCALL(REM_F32, "fmodf")
 HANDLE_LIBCALL(REM_F64, "fmod")
 HANDLE_LIBCALL(REM_F80, "fmodl")
-HANDLE_LIBCALL(REM_F128, "fmodl")
+HANDLE_LIBCALL(REM_F128, "fmodf128")
 HANDLE_LIBCALL(REM_PPCF128, "fmodl")
 HANDLE_LIBCALL(FMA_F32, "fmaf")
 HANDLE_LIBCALL(FMA_F64, "fma")
 HANDLE_LIBCALL(FMA_F80, "fmal")
-HANDLE_LIBCALL(FMA_F128, "fmal")
+HANDLE_LIBCALL(FMA_F128, "fmaf128")
 HANDLE_LIBCALL(FMA_PPCF128, "fmal")
 HANDLE_LIBCALL(POWI_F32, "__powisf2")
 HANDLE_LIBCALL(POWI_F64, "__powidf2")
@@ -128,117 +129,117 @@ HANDLE_LIBCALL(POWI_PPCF128, "__powitf2")
 HANDLE_LIBCALL(SQRT_F32, "sqrtf")
 HANDLE_LIBCALL(SQRT_F64, "sqrt")
 HANDLE_LIBCALL(SQRT_F80, "sqrtl")
-HANDLE_LIBCALL(SQRT_F128, "sqrtl")
+HANDLE_LIBCALL(SQRT_F128, "sqrtf128")
 HANDLE_LIBCALL(SQRT_PPCF128, "sqrtl")
 HANDLE_LIBCALL(CBRT_F32, "cbrtf")
 HANDLE_LIBCALL(CBRT_F64, "cbrt")
 HANDLE_LIBCALL(CBRT_F80, "cbrtl")
-HANDLE_LIBCALL(CBRT_F128, "cbrtl")
+HANDLE_LIBCALL(CBRT_F128, "cbrtf128")
 HANDLE_LIBCALL(CBRT_PPCF128, "cbrtl")
 HANDLE_LIBCALL(LOG_F32, "logf")
 HANDLE_LIBCALL(LOG_F64, "log")
 HANDLE_LIBCALL(LOG_F80, "logl")
-HANDLE_LIBCALL(LOG_F128, "logl")
+HANDLE_LIBCALL(LOG_F128, "logf128")
 HANDLE_LIBCALL(LOG_PPCF128, "logl")
 HANDLE_LIBCALL(LOG_FINITE_F32, "__logf_finite")
 HANDLE_LIBCALL(LOG_FINITE_F64, "__log_finite")
 HANDLE_LIBCALL(LOG_FINITE_F80, "__logl_finite")
-HANDLE_LIBCALL(LOG_FINITE_F128, "__logl_finite")
+HANDLE_LIBCALL(LOG_FINITE_F128, "__logf128_finite")
 HANDLE_LIBCALL(LOG_FINITE_PPCF128, "__logl_finite")
 HANDLE_LIBCALL(LOG2_F32, "log2f")
 HANDLE_LIBCALL(LOG2_F64, "log2")
 HANDLE_LIBCALL(LOG2_F80, "log2l")
-HANDLE_LIBCALL(LOG2_F128, "log2l")
+HANDLE_LIBCALL(LOG2_F128, "log2f128")
 HANDLE_LIBCALL(LOG2_PPCF128, "log2l")
 HANDLE_LIBCALL(LOG2_FINITE_F32, "__log2f_finite")
 HANDLE_LIBCALL(LOG2_FINITE_F64, "__log2_finite")
 HANDLE_LIBCALL(LOG2_FINITE_F80, "__log2l_finite")
-HANDLE_LIBCALL(LOG2_FINITE_F128, "__log2l_finite")
+HANDLE_LIBCALL(LOG2_FINITE_F128, "__log2f128_finite")
 HANDLE_LIBCALL(LOG2_FINITE_PPCF128, "__log2l_finite")
 HANDLE_LIBCALL(LOG10_F32, "log10f")
 HANDLE_LIBCALL(LOG10_F64, "log10")
 HANDLE_LIBCALL(LOG10_F80, "log10l")
-HANDLE_LIBCALL(LOG10_F128, "log10l")
+HANDLE_LIBCALL(LOG10_F128, "log10f128")
 HANDLE_LIBCALL(LOG10_PPCF128, "log10l")
 HANDLE_LIBCALL(LOG10_FINITE_F32, "__log10f_finite")
 HANDLE_LIBCALL(LOG10_FINITE_F64, "__log10_finite")
 HANDLE_LIBCALL(LOG10_FINITE_F80, "__log10l_finite")
-HANDLE_LIBCALL(LOG10_FINITE_F128, "__log10l_finite")
+HANDLE_LIBCALL(LOG10_FINITE_F128, "__log10f128_finite")
 HANDLE_LIBCALL(LOG10_FINITE_PPCF128, "__log10l_finite")
 HANDLE_LIBCALL(EXP_F32, "expf")
 HANDLE_LIBCALL(EXP_F64, "exp")
 HANDLE_LIBCALL(EXP_F80, "expl")
-HANDLE_LIBCALL(EXP_F128, "expl")
+HANDLE_LIBCALL(EXP_F128, "expf128")
 HANDLE_LIBCALL(EXP_PPCF128, "expl")
 HANDLE_LIBCALL(EXP_FINITE_F32, "__expf_finite")
 HANDLE_LIBCALL(EXP_FINITE_F64, "__exp_finite")
 HANDLE_LIBCALL(EXP_FINITE_F80, "__expl_finite")
-HANDLE_LIBCALL(EXP_FINITE_F128, "__expl_finite")
+HANDLE_LIBCALL(EXP_FINITE_F128, "__expf128_finite")
 HANDLE_LIBCALL(EXP_FINITE_PPCF128, "__expl_finite")
 HANDLE_LIBCALL(EXP2_F32, "exp2f")
 HANDLE_LIBCALL(EXP2_F64, "exp2")
 HANDLE_LIBCALL(EXP2_F80, "exp2l")
-HANDLE_LIBCALL(EXP2_F128, "exp2l")
+HANDLE_LIBCALL(EXP2_F128, "exp2f128")
 HANDLE_LIBCALL(EXP2_PPCF128, "exp2l")
 HANDLE_LIBCALL(EXP2_FINITE_F32, "__exp2f_finite")
 HANDLE_LIBCALL(EXP2_FINITE_F64, "__exp2_finite")
 HANDLE_LIBCALL(EXP2_FINITE_F80, "__exp2l_finite")
-HANDLE_LIBCALL(EXP2_FINITE_F128, "__exp2l_finite")
+HANDLE_LIBCALL(EXP2_FINITE_F128, "__exp2f128_finite")
 HANDLE_LIBCALL(EXP2_FINITE_PPCF128, "__exp2l_finite")
 HANDLE_LIBCALL(EXP10_F32, "exp10f")
 HANDLE_LIBCALL(EXP10_F64, "exp10")
 HANDLE_LIBCALL(EXP10_F80, "exp10l")
-HANDLE_LIBCALL(EXP10_F128, "exp10l")
+HANDLE_LIBCALL(EXP10_F128, "exp10f128")
 HANDLE_LIBCALL(EXP10_PPCF128, "exp10l")
 HANDLE_LIBCALL(SIN_F32, "sinf")
 HANDLE_LIBCALL(SIN_F64, "sin")
 HANDLE_LIBCALL(SIN_F80, "sinl")
-HANDLE_LIBCALL(SIN_F128, "sinl")
+HANDLE_LIBCALL(SIN_F128, "sinf128")
 HANDLE_LIBCALL(SIN_PPCF128, "sinl")
 HANDLE_LIBCALL(COS_F32, "cosf")
 HANDLE_LIBCALL(COS_F64, "cos")
 HANDLE_LIBCALL(COS_F80, "cosl")
-HANDLE_LIBCALL(COS_F128, "cosl")
+HANDLE_LIBCALL(COS_F128, "cosf128")
 HANDLE_LIBCALL(COS_PPCF128, "cosl")
 HANDLE_LIBCALL(TAN_F32, "tanf")
 HANDLE_LIBCALL(TAN_F64, "tan")
 HANDLE_LIBCALL(TAN_F80, "tanl")
-HANDLE_LIBCALL(TAN_F128,"tanl")
+HANDLE_LIBCALL(TAN_F128,"tanf128")
 HANDLE_LIBCALL(TAN_PPCF128, "tanl")
 HANDLE_LIBCALL(SINH_F32, "sinhf")
 HANDLE_LIBCALL(SINH_F64, "sinh")
 HANDLE_LIBCALL(SINH_F80, "sinhl")
-HANDLE_LIBCALL(SINH_F128, "sinhl")
+HANDLE_LIBCALL(SINH_F128, "sinhf128")
 HANDLE_LIBCALL(SINH_PPCF128, "sinhl")
 HANDLE_LIBCALL(COSH_F32, "coshf")
 HANDLE_LIBCALL(COSH_F64, "cosh")
 HANDLE_LIBCALL(COSH_F80, "coshl")
-HANDLE_LIBCALL(COSH_F128, "coshl")
+HANDLE_LIBCALL(COSH_F128, "coshf128")
 HANDLE_LIBCALL(COSH_PPCF128, "coshl")
 HANDLE_LIBCALL(TANH_F32, "tanhf")
 HANDLE_LIBCALL(TANH_F64, "tanh")
 HANDLE_LIBCALL(TANH_F80, "tanhl")
-HANDLE_LIBCALL(TANH_F128,"tanhl")
+HANDLE_LIBCALL(TANH_F128,"tanhf128")
 HANDLE_LIBCALL(TANH_PPCF128, "tanhl")
 HANDLE_LIBCALL(ASIN_F32, "asinf")
 HANDLE_LIBCALL(ASIN_F64, "asin")
 HANDLE_LIBCALL(ASIN_F80, "asinl")
-HANDLE_LIBCALL(ASIN_F128, "asinl")
+HANDLE_LIBCALL(ASIN_F128, "asinf128")
 HANDLE_LIBCALL(ASIN_PPCF128, "asinl")
 HANDLE_LIBCALL(ACOS_F32, "acosf")
 HANDLE_LIBCALL(ACOS_F64, "acos")
 HANDLE_LIBCALL(ACOS_F80, "acosl")
-HANDLE_LIBCALL(ACOS_F128, "acosl")
+HANDLE_LIBCALL(ACOS_F128, "acosf128")
 HANDLE_LIBCALL(ACOS_PPCF128, "acosl")
 HANDLE_LIBCALL(ATAN_F32, "atanf")
 HANDLE_LIBCALL(ATAN_F64, "atan")
 HANDLE_LIBCALL(ATAN_F80, "atanl")
-HANDLE_LIBCALL(ATAN_F128,"atanl")
+HANDLE_LIBCALL(ATAN_F128,"atanf128")
 HANDLE_LIBCALL(ATAN_PPCF128, "atanl")
 HANDLE_LIBCALL(ATAN2_F32, "atan2f")
 HANDLE_LIBCALL(ATAN2_F64, "atan2")
 HANDLE_LIBCALL(ATAN2_F80, "atan2l")
-HANDLE_LIBCALL(ATAN2_F128,"atan2l")
+HANDLE_LIBCALL(ATAN2_F128,"atan2f128")
 HANDLE_LIBCALL(ATAN2_PPCF128, "atan2l")
 HANDLE_LIBCALL(SINCOS_F32, nullptr)
 HANDLE_LIBCALL(SINCOS_F64, nullptr)
@@ -250,122 +251,122 @@ HANDLE_LIBCALL(SINCOS_STRET_F64, nullptr)
 HANDLE_LIBCALL(POW_F32, "powf")
 HANDLE_LIBCALL(POW_F64, "pow")
 HANDLE_LIBCALL(POW_F80, "powl")
-HANDLE_LIBCALL(POW_F128, "powl")
+HANDLE_LIBCALL(POW_F128, "powf128")
 HANDLE_LIBCALL(POW_PPCF128, "powl")
 HANDLE_LIBCALL(POW_FINITE_F32, "__powf_finite")
 HANDLE_LIBCALL(POW_FINITE_F64, "__pow_finite")
 HANDLE_LIBCALL(POW_FINITE_F80, "__powl_finite")
-HANDLE_LIBCALL(POW_FINITE_F128, "__powl_finite")
+HANDLE_LIBCALL(POW_FINITE_F128, "__powf128_finite")
 HANDLE_LIBCALL(POW_FINITE_PPCF128, "__powl_finite")
 HANDLE_LIBCALL(CEIL_F32, "ceilf")
 HANDLE_LIBCALL(CEIL_F64, "ceil")
 HANDLE_LIBCALL(CEIL_F80, "ceill")
-HANDLE_LIBCALL(CEIL_F128, "ceill")
+HANDLE_LIBCALL(CEIL_F128, "ceilf128")
 HANDLE_LIBCALL(CEIL_PPCF128, "ceill")
 HANDLE_LIBCALL(TRUNC_F32, "truncf")
 HANDLE_LIBCALL(TRUNC_F64, "trunc")
 HANDLE_LIBCALL(TRUNC_F80, "truncl")
-HANDLE_LIBCALL(TRUNC_F128, "truncl")
+HANDLE_LIBCALL(TRUNC_F128, "truncf128")
 HANDLE_LIBCALL(TRUNC_PPCF128, "truncl")
 HANDLE_LIBCALL(RINT_F32, "rintf")
 HANDLE_LIBCALL(RINT_F64, "rint")
 HANDLE_LIBCALL(RINT_F80, "rintl")
-HANDLE_LIBCALL(RINT_F128, "rintl")
+HANDLE_LIBCALL(RINT_F128, "rintf128")
 HANDLE_LIBCALL(RINT_PPCF128, "rintl")
 HANDLE_LIBCALL(NEARBYINT_F32, "nearbyintf")
 HANDLE_LIBCALL(NEARBYINT_F64, "nearbyint")
 HANDLE_LIBCALL(NEARBYINT_F80, "nearbyintl")
-HANDLE_LIBCALL(NEARBYINT_F128, "nearbyintl")
+HANDLE_LIBCALL(NEARBYINT_F128, "nearbyintf128")
 HANDLE_LIBCALL(NEARBYINT_PPCF128, "nearbyintl")
 HANDLE_LIBCALL(ROUND_F32, "roundf")
 HANDLE_LIBCALL(ROUND_F64, "round")
 HANDLE_LIBCALL(ROUND_F80, "roundl")
-HANDLE_LIBCALL(ROUND_F128, "roundl")
+HANDLE_LIBCALL(ROUND_F128, "roundf128")
 HANDLE_LIBCALL(ROUND_PPCF128, "roundl")
 HANDLE_LIBCALL(ROUNDEVEN_F32, "roundevenf")
 HANDLE_LIBCALL(ROUNDEVEN_F64, "roundeven")
 HANDLE_LIBCALL(ROUNDEVEN_F80, "roundevenl")
-HANDLE_LIBCALL(ROUNDEVEN_F128, "roundevenl")
+HANDLE_LIBCALL(ROUNDEVEN_F128, "roundevenf128")
 HANDLE_LIBCALL(ROUNDEVEN_PPCF128, "roundevenl")
 HANDLE_LIBCALL(FLOOR_F32, "floorf")
 HANDLE_LIBCALL(FLOOR_F64, "floor")
 HANDLE_LIBCALL(FLOOR_F80, "floorl")
-HANDLE_LIBCALL(FLOOR_F128, "floorl")
+HANDLE_LIBCALL(FLOOR_F128, "floorf128")
 HANDLE_LIBCALL(FLOOR_PPCF128, "floorl")
 HANDLE_LIBCALL(COPYSIGN_F32, "copysignf")
 HANDLE_LIBCALL(COPYSIGN_F64, "copysign")
 HANDLE_LIBCALL(COPYSIGN_F80, "copysignl")
-HANDLE_LIBCALL(COPYSIGN_F128, "copysignl")
+HANDLE_LIBCALL(COPYSIGN_F128, "copysignf128")
 HANDLE_LIBCALL(COPYSIGN_PPCF128, "copysignl")
 HANDLE_LIBCALL(FMIN_F32, "fminf")
 HANDLE_LIBCALL(FMIN_F64, "fmin")
 HANDLE_LIBCALL(FMIN_F80, "fminl")
-HANDLE_LIBCALL(FMIN_F128, "fminl")
+HANDLE_LIBCALL(FMIN_F128, "fminf128")
 HANDLE_LIBCALL(FMIN_PPCF128, "fminl")
 HANDLE_LIBCALL(FMAX_F32, "fmaxf")
 HANDLE_LIBCALL(FMAX_F64, "fmax")
 HANDLE_LIBCALL(FMAX_F80, "fmaxl")
-HANDLE_LIBCALL(FMAX_F128, "fmaxl")
+HANDLE_LIBCALL(FMAX_F128, "fmaxf128")
 HANDLE_LIBCALL(FMAX_PPCF128, "fmaxl")
 HANDLE_LIBCALL(FMINIMUM_F32, "fminimumf")
 HANDLE_LIBCALL(FMINIMUM_F64, "fminimum")
 HANDLE_LIBCALL(FMINIMUM_F80, "fminimuml")
-HANDLE_LIBCALL(FMINIMUM_F128, "fminimuml")
+HANDLE_LIBCALL(FMINIMUM_F128, "fminimumf128")
 HANDLE_LIBCALL(FMINIMUM_PPCF128, "fminimuml")
 HANDLE_LIBCALL(FMAXIMUM_F32, "fmaximumf")
 HANDLE_LIBCALL(FMAXIMUM_F64, "fmaximum")
 HANDLE_LIBCALL(FMAXIMUM_F80, "fmaximuml")
-HANDLE_LIBCALL(FMAXIMUM_F128, "fmaximuml")
+HANDLE_LIBCALL(FMAXIMUM_F128, "fmaximumf128")
 HANDLE_LIBCALL(FMAXIMUM_PPCF128, "fmaximum_numl")
 HANDLE_LIBCALL(FMINIMUMNUM_F32, "fminimum_numf")
 HANDLE_LIBCALL(FMINIMUMNUM_F64, "fminimum_num")
 HANDLE_LIBCALL(FMINIMUMNUM_F80, "fminimum_numl")
-HANDLE_LIBCALL(FMINIMUMNUM_F128, "fminimum_numl")
+HANDLE_LIBCALL(FMINIMUMNUM_F128, "fminimum_numf128")
 HANDLE_LIBCALL(FMINIMUMNUM_PPCF128, "fminimum_numl")
 HANDLE_LIBCALL(FMAXIMUMNUM_F32, "fmaximum_numf")
 HANDLE_LIBCALL(FMAXIMUMNUM_F64, "fmaximum_num")
 HANDLE_LIBCALL(FMAXIMUMNUM_F80, "fmaximum_numl")
-HANDLE_LIBCALL(FMAXIMUMNUM_F128, "fmaximum_numl")
+HANDLE_LIBCALL(FMAXIMUMNUM_F128, "fmaximum_numf128")
 HANDLE_LIBCALL(FMAXIMUMNUM_PPCF128, "fmaximum_numl")
 HANDLE_LIBCALL(LROUND_F32, "lroundf")
 HANDLE_LIBCALL(LROUND_F64, "lround")
 HANDLE_LIBCALL(LROUND_F80, "lroundl")
-HANDLE_LIBCALL(LROUND_F128, "lroundl")
+HANDLE_LIBCALL(LROUND_F128, "lroundf128")
 HANDLE_LIBCALL(LROUND_PPCF128, "lroundl")
 HANDLE_LIBCALL(LLROUND_F32, "llroundf")
 HANDLE_LIBCALL(LLROUND_F64, "llround")
 HANDLE_LIBCALL(LLROUND_F80, "llroundl")
-HANDLE_LIBCALL(LLROUND_F128, "llroundl")
+HANDLE_LIBCALL(LLROUND_F128, "llroundf128")
 HANDLE_LIBCALL(LLROUND_PPCF128, "llroundl")
 HANDLE_LIBCALL(LRINT_F32, "lrintf")
 HANDLE_LIBCALL(LRINT_F64, "lrint")
 HANDLE_LIBCALL(LRINT_F80, "lrintl")
-HANDLE_LIBCALL(LRINT_F128, "lrintl")
+HANDLE_LIBCALL(LRINT_F128, "lrintf128")
 HANDLE_LIBCALL(LRINT_PPCF128, "lrintl")
 HANDLE_LIBCALL(LLRINT_F32, "llrintf")
 HANDLE_LIBCALL(LLRINT_F64, "llrint")
 HANDLE_LIBCALL(LLRINT_F80, "llrintl")
-HANDLE_LIBCALL(LLRINT_F128, "llrintl")
+HANDLE_LIBCALL(LLRINT_F128, "llrintf128")
 HANDLE_LIBCALL(LLRINT_PPCF128, "llrintl")
 HANDLE_LIBCALL(LDEXP_F32, "ldexpf")
 HANDLE_LIBCALL(LDEXP_F64, "ldexp")
 HANDLE_LIBCALL(LDEXP_F80, "ldexpl")
-HANDLE_LIBCALL(LDEXP_F128, "ldexpl")
+HANDLE_LIBCALL(LDEXP_F128, "ldexpf128")
 HANDLE_LIBCALL(LDEXP_PPCF128, "ldexpl")
 HANDLE_LIBCALL(FREXP_F32, "frexpf")
 HANDLE_LIBCALL(FREXP_F64, "frexp")
 HANDLE_LIBCALL(FREXP_F80, "frexpl")
-HANDLE_LIBCALL(FREXP_F128, "frexpl")
+HANDLE_LIBCALL(FREXP_F128, "frexpf128")
 HANDLE_LIBCALL(FREXP_PPCF128, "frexpl")
 HANDLE_LIBCALL(SINCOSPI_F32, "sincospif")
 HANDLE_LIBCALL(SINCOSPI_F64, "sincospi")
 HANDLE_LIBCALL(SINCOSPI_F80, "sincospil")
-HANDLE_LIBCALL(SINCOSPI_F128, "sincospil")
+HANDLE_LIBCALL(SINCOSPI_F128, "sincospif128")
 HANDLE_LIBCALL(SINCOSPI_PPCF128, "sincospil")
 HANDLE_LIBCALL(MODF_F32, "modff")
 HANDLE_LIBCALL(MODF_F64, "modf")
 HANDLE_LIBCALL(MODF_F80, "modfl")
-HANDLE_LIBCALL(MODF_F128, "modfl")
+HANDLE_LIBCALL(MODF_F128, "modff128")
 HANDLE_LIBCALL(MODF_PPCF128, "modfl")
 
 // Floating point environment

llvm/include/llvm/IR/RuntimeLibcalls.h

@@ -20,6 +20,17 @@
 #include "llvm/TargetParser/Triple.h"
 
 namespace llvm {
+
+/// Library names to use for `fp128` libcalls.
+enum class F128LibcallFormat {
+  /// C23 `*f128` lowering, e.g. `sinf128`
+  Default = 0,
+  /// `long double` *l` lowering, e.g. `sinl`.
+  LongDouble = 1,
+  // If needed, this could be extended with an option for `q` suffixes from
+  // libquadmath.
+};
+
 namespace RTLIB {
 
 /// RTLIB::Libcall enum - This enum defines all of the runtime library calls
@@ -97,6 +108,13 @@ struct RuntimeLibcallsInfo {
   /// Set default libcall names. If a target wants to opt-out of a libcall it
   /// should be placed here.
   void initLibcalls(const Triple &TT);
+
+  /// Set a specific lowering convention for `fp128` math libcalls.
+  ///
+  /// By default, `fp128` math functions get lowered to the C23 `sinf128`-
+  /// style symbols. This allows overriding with `sinl`-style symbols on
+  /// platforms where `long double` is known to be identical to _Float128.
+  void setF128LibcallFormat(F128LibcallFormat Format);
 };
 
 } // namespace RTLIB

llvm/include/llvm/TargetParser/Triple.h

@@ -262,13 +262,13 @@ class Triple {
     EABIHF,
     Android,
     Musl,
-    MuslABIN32,
-    MuslABI64,
-    MuslEABI,
-    MuslEABIHF,
-    MuslF32,
-    MuslSF,
-    MuslX32,
+    MuslABIN32, // MIPS N32 ABI
+    MuslABI64,  // MIPS N64 ABI
+    MuslEABI,   // Arm32 EABI
+    MuslEABIHF, // Arm32 EABI + HF
+    MuslF32,    // LoongArch ILP32F/LP64F
+    MuslSF,     // LoongArch ILP32S/LP64S
+    MuslX32,    // Musl using 32-bit ABI on x86_64
     LLVM,
 
     MSVC,
@@ -1231,6 +1231,12 @@ class Triple {
   /// or an invalid version tuple if this triple doesn't have one.
   VersionTuple getMinimumSupportedOSVersion() const;
 
+  /// Check whether (1) f128 is the same format as `long double`, and (2)
+  /// `*f128` symbols are likely unavailable. In other words, platforms for
+  /// which this returns true may safely use sqrtl instead of sqrtf128 and
+  /// should do so because sqrtf128 would probably error at link time.
+  bool shouldLowerf128AsLongDouble() const;
+
   /// @}
   /// @name Static helpers for IDs.
   /// @{