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Merged
merged 19 commits into from
Nov 29, 2025
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[SPARC] Properly handle CC for long double on sparc32 #162226

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ff3ad98
[WIP][SPARC] Properly handle CC for long double on sparc32
koachan Oct 7, 2025
84b1b6d
Implement indirect argument handling in LowerCall/FormalArguments
koachan Oct 13, 2025
0c673ae
Update tests
koachan Oct 14, 2025
aee2895
Remove redundant checks
koachan Oct 15, 2025
f62d4df
Un-xfail tests that are now passing
koachan Oct 20, 2025
b283fee
Fix long double __Complex returns
koachan Oct 29, 2025
8724a59
Apply suggestions
koachan Nov 10, 2025
5e8aa4a
Try to make complex f128 work
koachan Nov 18, 2025
f9ed024
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koachan Nov 18, 2025
ff6e10e
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koachan Nov 23, 2025
e38af2a
Use CCIfConsecutiveRegs
koachan Nov 24, 2025
cb69bc6
inreg should only apply to long double _Complex
koachan Nov 24, 2025
34bfc88
Use autogenerated tests
koachan Nov 24, 2025
69e93a8
Fix direct fp128 arg passing
koachan Nov 24, 2025
16391d0
Add FIXME note and stack argument test
koachan Nov 24, 2025
2481bb8
Separate ABI tests
koachan Nov 24, 2025
5b13c01
Apply suggestions
koachan Nov 25, 2025
e383d75
Change condition and reformat
koachan Nov 26, 2025
291824c
Define __LONG_DOUBLE_128__
koachan Nov 27, 2025
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7 changes: 7 additions & 0 deletions clang/lib/Basic/Targets/Sparc.h
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Expand Up @@ -166,6 +166,13 @@ class LLVM_LIBRARY_VISIBILITY SparcV8TargetInfo : public SparcTargetInfo {
PtrDiffType = SignedLong;
break;
}

// The SPARCv8 System V ABI has long double 128-bits in size, but 64-bit
// aligned.
LongDoubleWidth = 128;
LongDoubleAlign = 64;
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@efriedma-quic efriedma-quic Oct 7, 2025

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You probably also need to fix the datalayout

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@koachan koachan Oct 9, 2025

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It already has the f128:64 part, so I think I'm good here?

LongDoubleFormat = &llvm::APFloat::IEEEquad();

// Up to 32 bits (V8) or 64 bits (V9) are lock-free atomic, but we're
// willing to do atomic ops on up to 64 bits.
MaxAtomicPromoteWidth = 64;
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33 changes: 24 additions & 9 deletions clang/lib/CodeGen/Targets/Sparc.cpp
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Expand Up @@ -26,23 +26,38 @@ class SparcV8ABIInfo : public DefaultABIInfo {

private:
ABIArgInfo classifyReturnType(QualType RetTy) const;
ABIArgInfo classifyArgumentType(QualType Ty) const;
void computeInfo(CGFunctionInfo &FI) const override;
};
} // end anonymous namespace

ABIArgInfo SparcV8ABIInfo::classifyReturnType(QualType Ty) const {
const auto *CT = Ty->getAs<ComplexType>();
const auto *BT = Ty->getAs<BuiltinType>();
if (CT)
BT = CT->getElementType()->getAs<BuiltinType>();
bool IsLongDouble = BT && BT->getKind() == BuiltinType::LongDouble;

ABIArgInfo
SparcV8ABIInfo::classifyReturnType(QualType Ty) const {
if (Ty->isAnyComplexType()) {
return ABIArgInfo::getDirect();
}
else {
return DefaultABIInfo::classifyReturnType(Ty);
}
// long double _Complex is special in that it should be marked as inreg.
if (CT)
return IsLongDouble ? ABIArgInfo::getDirectInReg()
: ABIArgInfo::getDirect();

if (IsLongDouble)
return getNaturalAlignIndirect(Ty, getDataLayout().getAllocaAddrSpace());

return DefaultABIInfo::classifyReturnType(Ty);
}

void SparcV8ABIInfo::computeInfo(CGFunctionInfo &FI) const {
ABIArgInfo SparcV8ABIInfo::classifyArgumentType(QualType Ty) const {
if (const auto *BT = Ty->getAs<BuiltinType>();
BT && BT->getKind() == BuiltinType::LongDouble)
return getNaturalAlignIndirect(Ty, getDataLayout().getAllocaAddrSpace());

return DefaultABIInfo::classifyArgumentType(Ty);
}

void SparcV8ABIInfo::computeInfo(CGFunctionInfo &FI) const {
FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
for (auto &Arg : FI.arguments())
Arg.info = classifyArgumentType(Arg.type);
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36 changes: 33 additions & 3 deletions clang/test/CodeGen/Sparc/sparcv8-abi.c
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@@ -1,22 +1,52 @@
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --filter "^define |^entry:" --version 6
// RUN: %clang_cc1 -triple sparc-unknown-unknown -emit-llvm %s -o - | FileCheck %s

// CHECK-LABEL: define{{.*}} { float, float } @p(ptr noundef byval({ float, float }) align 4 %a, ptr noundef byval({ float, float }) align 4 %b) #0 {
float __complex__
// CHECK-LABEL: define dso_local { float, float } @p(
// CHECK-SAME: ptr noundef byval({ float, float }) align 4 [[A:%.*]], ptr noundef byval({ float, float }) align 4 [[B:%.*]]) #[[ATTR0:[0-9]+]] {
// CHECK: [[ENTRY:.*:]]
//
p (float __complex__ a, float __complex__ b)
{
return 0;
}

// CHECK-LABEL: define{{.*}} { double, double } @q(ptr noundef byval({ double, double }) align 8 %a, ptr noundef byval({ double, double }) align 8 %b) #0 {
double __complex__
// CHECK-LABEL: define dso_local { double, double } @q(
// CHECK-SAME: ptr noundef byval({ double, double }) align 8 [[A:%.*]], ptr noundef byval({ double, double }) align 8 [[B:%.*]]) #[[ATTR0]] {
// CHECK: [[ENTRY:.*:]]
//
q (double __complex__ a, double __complex__ b)
{
return 0;
}

// CHECK-LABEL: define{{.*}} { i64, i64 } @r(ptr noundef byval({ i64, i64 }) align 8 %a, ptr noundef byval({ i64, i64 }) align 8 %b) #0 {
long long __complex__
// CHECK-LABEL: define dso_local { i64, i64 } @r(
// CHECK-SAME: ptr noundef byval({ i64, i64 }) align 8 [[A:%.*]], ptr noundef byval({ i64, i64 }) align 8 [[B:%.*]]) #[[ATTR0]] {
// CHECK: [[ENTRY:.*:]]
//
r (long long __complex__ a, long long __complex__ b)
{
return 0;
}

long double
// CHECK-LABEL: define dso_local void @s(
// CHECK-SAME: ptr dead_on_unwind noalias writable sret(fp128) align 8 [[AGG_RESULT:%.*]], ptr noundef byval(fp128) align 8 [[TMP0:%.*]]) #[[ATTR0]] {
// CHECK: [[ENTRY:.*:]]
//
s(long double a)
{
return 0;
}

long double _Complex
// CHECK-LABEL: define dso_local inreg { fp128, fp128 } @t(
// CHECK-SAME: ptr noundef byval({ fp128, fp128 }) align 8 [[A:%.*]]) #[[ATTR0]] {
// CHECK: [[ENTRY:.*:]]
//
t(long double _Complex a)
{
return 0;
}
22 changes: 11 additions & 11 deletions clang/test/Preprocessor/init.c
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Expand Up @@ -1106,19 +1106,19 @@
// SPARC:#define __INT_LEAST8_MAX__ 127
// SPARC:#define __INT_LEAST8_TYPE__ signed char
// SPARC:#define __INT_MAX__ 2147483647
// SPARC:#define __LDBL_DENORM_MIN__ 4.9406564584124654e-324L
// SPARC:#define __LDBL_DIG__ 15
// SPARC:#define __LDBL_EPSILON__ 2.2204460492503131e-16L
// SPARC:#define __LDBL_DENORM_MIN__ 6.47517511943802511092443895822764655e-4966L
// SPARC:#define __LDBL_DIG__ 33
// SPARC:#define __LDBL_EPSILON__ 1.92592994438723585305597794258492732e-34L
// SPARC:#define __LDBL_HAS_DENORM__ 1
// SPARC:#define __LDBL_HAS_INFINITY__ 1
// SPARC:#define __LDBL_HAS_QUIET_NAN__ 1
// SPARC:#define __LDBL_MANT_DIG__ 53
// SPARC:#define __LDBL_MAX_10_EXP__ 308
// SPARC:#define __LDBL_MAX_EXP__ 1024
// SPARC:#define __LDBL_MAX__ 1.7976931348623157e+308L
// SPARC:#define __LDBL_MIN_10_EXP__ (-307)
// SPARC:#define __LDBL_MIN_EXP__ (-1021)
// SPARC:#define __LDBL_MIN__ 2.2250738585072014e-308L
// SPARC:#define __LDBL_MANT_DIG__ 113
// SPARC:#define __LDBL_MAX_10_EXP__ 4932
// SPARC:#define __LDBL_MAX_EXP__ 16384
// SPARC:#define __LDBL_MAX__ 1.18973149535723176508575932662800702e+4932L
// SPARC:#define __LDBL_MIN_10_EXP__ (-4931)
// SPARC:#define __LDBL_MIN_EXP__ (-16381)
// SPARC:#define __LDBL_MIN__ 3.36210314311209350626267781732175260e-4932L
// SPARC:#define __LONG_LONG_MAX__ 9223372036854775807LL
// SPARC:#define __LONG_MAX__ 2147483647L
// SPARC-NOT:#define __LP64__
Expand All @@ -1134,7 +1134,7 @@
// SPARC:#define __SIZEOF_DOUBLE__ 8
// SPARC:#define __SIZEOF_FLOAT__ 4
// SPARC:#define __SIZEOF_INT__ 4
// SPARC:#define __SIZEOF_LONG_DOUBLE__ 8
// SPARC:#define __SIZEOF_LONG_DOUBLE__ 16
// SPARC:#define __SIZEOF_LONG_LONG__ 8
// SPARC:#define __SIZEOF_LONG__ 4
// SPARC:#define __SIZEOF_POINTER__ 4
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4 changes: 2 additions & 2 deletions compiler-rt/lib/builtins/CMakeLists.txt
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Expand Up @@ -1009,9 +1009,9 @@ else ()
list(APPEND BUILTIN_CFLAGS_${arch} -fomit-frame-pointer -DCOMPILER_RT_ARMHF_TARGET)
endif()

# For RISCV32, we must force enable int128 for compiling long
# For RISCV32 and 32-bit SPARC, we must force enable int128 for compiling long
# double routines.
if(COMPILER_RT_ENABLE_SOFTWARE_INT128 OR "${arch}" STREQUAL "riscv32")
if(COMPILER_RT_ENABLE_SOFTWARE_INT128 OR "${arch}" STREQUAL "riscv32" OR ("${arch}" STREQUAL "sparc" AND NOT CMAKE_COMPILER_IS_GNUCC))
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@s-barannikov s-barannikov Nov 26, 2025

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Sorry for going back and forth, I suppose -fforce-enable-in128 isn't supported by riscv-gcc either, so it should be the same as in the file below.

When compiled with gcc, how is the library supposed to link if int128 routines are not compiled in?

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@koachan koachan Nov 26, 2025

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When compiled with gcc, how is the library supposed to link if int128 routines are not compiled in?

I suppose in that case the library will lack long double routines? @rorth probably know better about this.

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@rorth rorth Nov 26, 2025

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When compiled with gcc, how is the library supposed to link if int128 routines are not compiled in?

I suppose in that case the library will lack long double routines? @rorth probably know better about this.

I've no idea right now (have tried to forget all of this ;-). Besides, I'm so busy with the upcoming GCC 16 release that I've no time left for LLVM.

What I've done in the past is do build with both clang and gcc as build compiler, 2-stage builds with clang, 1-stage ones with gcc. And note that the compiler-rt tests still aren't run in runtime builds (which is the default these days), not even a target to do so manually, so I've always used

 -DLLVM_ENABLE_PROJECTS=compiler-rt

to avoid that.

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@koachan koachan Nov 27, 2025

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Thanks for the hint! I tried running it and seems like I found some other long double related failures:

SanitizerCommon-asan-sparc-Linux :: printf-ldbl.c
SanitizerCommon-asan-sparc-Linux :: scanf-ldbl.c
SanitizerCommon-ubsan-sparc-Linux :: printf-ldbl.c                                                                                                                                                                                                                            
SanitizerCommon-ubsan-sparc-Linux :: scanf-ldbl.c

Because clang lowers the printf/scanf calls into something like __nldbl_snprintf and __nldbl___isoc99_sscanf...
Seems like I missed defining __LONG_DOUBLE_128__, lemme fix this.

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@koachan koachan Nov 28, 2025

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Okay seems like after __LONG_DOUBLE_128__ is added the issue is gone.

list(APPEND BUILTIN_CFLAGS_${arch} -fforce-enable-int128)
endif()

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2 changes: 1 addition & 1 deletion compiler-rt/test/builtins/CMakeLists.txt
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Expand Up @@ -48,7 +48,7 @@ foreach(arch ${BUILTIN_TEST_ARCH})
string(REPLACE ";" " " BUILTINS_TEST_TARGET_CFLAGS "${BUILTINS_TEST_TARGET_CFLAGS}")
endif()

if (COMPILER_RT_ENABLE_SOFTWARE_INT128 OR ${arch} STREQUAL "riscv32")
if (COMPILER_RT_ENABLE_SOFTWARE_INT128 OR "${arch}" MATCHES "riscv32|sparc$" AND NOT CMAKE_COMPILER_IS_GNUCC)
list(APPEND BUILTINS_TEST_TARGET_CFLAGS -fforce-enable-int128)
string(REPLACE ";" " " BUILTINS_TEST_TARGET_CFLAGS "${BUILTINS_TEST_TARGET_CFLAGS}")
endif()
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3 changes: 0 additions & 3 deletions compiler-rt/test/sanitizer_common/TestCases/printf-ldbl.c
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@@ -1,8 +1,5 @@
// RUN: %clang %s -o %t && %run %t 2>&1

// Issue #41838
// XFAIL: sparc-target-arch && target={{.*solaris.*}}

#include <assert.h>
#include <stdio.h>
#include <string.h>
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3 changes: 0 additions & 3 deletions compiler-rt/test/sanitizer_common/TestCases/scanf-ldbl.c
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@@ -1,8 +1,5 @@
// RUN: %clang %s -o %t && %run %t 2>&1

// Issue #41838
// XFAIL: sparc-target-arch && target={{.*solaris.*}}

#include <assert.h>
#include <stdio.h>
#include <string.h>
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3 changes: 0 additions & 3 deletions compiler-rt/test/ubsan/TestCases/Float/cast-overflow.cpp
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Expand Up @@ -9,9 +9,6 @@
// RUN: %run %t 6 2>&1 | FileCheck %s --check-prefix=CHECK-6
// RUN: %run %t 7 2>&1 | FileCheck %s --check-prefix=CHECK-7

// Issue #41838
// XFAIL: sparc-target-arch && target={{.*solaris.*}}

// This test assumes float and double are IEEE-754 single- and double-precision.

#if defined(__APPLE__)
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3 changes: 0 additions & 3 deletions compiler-rt/test/ubsan/TestCases/Misc/log-path_test.cpp
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Expand Up @@ -24,9 +24,6 @@
// FIXME: log_path is not supported on Windows yet.
// XFAIL: target={{.*windows-msvc.*}}

// Issue #41838
// XFAIL: sparc-target-arch && target={{.*solaris.*}}

#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[]) {
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6 changes: 4 additions & 2 deletions llvm/lib/Target/Sparc/SparcCallingConv.td
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Expand Up @@ -17,23 +17,25 @@
def CC_Sparc32 : CallingConv<[
// Custom assign SRet to [sp+64].
CCIfSRet<CCCustom<"CC_Sparc_Assign_SRet">>,
// f128 arguments are passed indirectly, using i32 pointers.
CCIfType<[f128], CCPassIndirect<i32>>,
// i32 f32 arguments get passed in integer registers if there is space.
CCIfType<[i32, f32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
// f64 arguments are split and passed through registers or through stack.
CCIfType<[f64], CCCustom<"CC_Sparc_Assign_Split_64">>,
// As are v2i32 arguments (this would be the default behavior for
// v2i32 if it wasn't allocated to the IntPair register-class)
CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Split_64">>,


// Alternatively, they are assigned to the stack in 4-byte aligned units.
CCAssignToStack<4, 4>
]>;


def RetCC_Sparc32 : CallingConv<[
CCIfType<[i32], CCAssignToReg<[I0, I1, I2, I3, I4, I5]>>,
CCIfType<[f32], CCAssignToReg<[F0, F1, F2, F3]>>,
CCIfType<[f64], CCAssignToReg<[D0, D1]>>,
CCIfType<[f128], CCIfInReg<CCIfConsecutiveRegs<CCAssignToReg<[Q0, Q1]>>>>,
CCIfType<[v2i32], CCCustom<"CC_Sparc_Assign_Ret_Split_64">>
]>;

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