Skip to content

[clang] constexpr built-in elementwise popcount function. #117473

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 8 commits into from
Nov 26, 2024
Merged

[clang] constexpr built-in elementwise popcount function. #117473

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
8 commits
Select commit Hold shift + click to select a range
95f2b6b
constexpr elementwise popcount
c8ef Nov 24, 2024
316f608
fix bug
c8ef Nov 24, 2024
5dba71f
fix bug; add more test cases
c8ef Nov 24, 2024
60216a4
fix test
c8ef Nov 24, 2024
6ec9aa5
fix test
c8ef Nov 24, 2024
af8ef3a
address review comments
c8ef Nov 25, 2024
dbf9379
Update constant_builtins_vector.cpp
c8ef Nov 25, 2024
55f945c
add doc
c8ef Nov 26, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 3 additions & 0 deletions clang/docs/LanguageExtensions.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -647,6 +647,9 @@ elementwise to the input.

Unless specified otherwise operation(±0) = ±0 and operation(±infinity) = ±infinity

The integer elementwise intrinsics, including ``__builtin_elementwise_popcount``,
can be called in a ``constexpr`` context.

============================================== ====================================================================== =========================================
Name Operation Supported element types
============================================== ====================================================================== =========================================
Expand Down
1 change: 1 addition & 0 deletions clang/docs/ReleaseNotes.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -370,6 +370,7 @@ Non-comprehensive list of changes in this release
- ``__builtin_reduce_mul`` function can now be used in constant expressions.
- ``__builtin_reduce_and`` function can now be used in constant expressions.
- ``__builtin_reduce_or`` and ``__builtin_reduce_xor`` functions can now be used in constant expressions.
- ``__builtin_elementwise_popcount`` function can now be used in constant expressions.

New Compiler Flags
------------------
Expand Down
2 changes: 1 addition & 1 deletion clang/include/clang/Basic/Builtins.td
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1354,7 +1354,7 @@ def ElementwiseLog10 : Builtin {

def ElementwisePopcount : Builtin {
let Spellings = ["__builtin_elementwise_popcount"];
let Attributes = [NoThrow, Const, CustomTypeChecking];
let Attributes = [NoThrow, Const, CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}

Expand Down
31 changes: 31 additions & 0 deletions clang/lib/AST/ExprConstant.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11005,6 +11005,7 @@ namespace {
bool VisitUnaryImag(const UnaryOperator *E);
bool VisitBinaryOperator(const BinaryOperator *E);
bool VisitUnaryOperator(const UnaryOperator *E);
bool VisitCallExpr(const CallExpr *E);
bool VisitConvertVectorExpr(const ConvertVectorExpr *E);
bool VisitShuffleVectorExpr(const ShuffleVectorExpr *E);

Expand Down Expand Up @@ -11302,6 +11303,35 @@ static bool handleVectorElementCast(EvalInfo &Info, const FPOptions FPO,
return false;
}

bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
if (!IsConstantEvaluatedBuiltinCall(E))
return ExprEvaluatorBaseTy::VisitCallExpr(E);

switch (E->getBuiltinCallee()) {
default:
return false;
case Builtin::BI__builtin_elementwise_popcount: {
APValue Source;
if (!EvaluateAsRValue(Info, E->getArg(0), Source))
return false;

QualType DestEltTy = E->getType()->castAs<VectorType>()->getElementType();
unsigned SourceLen = Source.getVectorLength();
SmallVector<APValue, 4> ResultElements;
ResultElements.reserve(SourceLen);

for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
APSInt Elt = Source.getVectorElt(EltNum).getInt();
ResultElements.push_back(
APValue(APSInt(APInt(Info.Ctx.getIntWidth(DestEltTy), Elt.popcount()),
DestEltTy->isUnsignedIntegerOrEnumerationType())));
}

return Success(APValue(ResultElements.data(), ResultElements.size()), E);
}
}
}

bool VectorExprEvaluator::VisitConvertVectorExpr(const ConvertVectorExpr *E) {
APValue Source;
QualType SourceVecType = E->getSrcExpr()->getType();
Expand Down Expand Up @@ -13118,6 +13148,7 @@ bool IntExprEvaluator::VisitBuiltinCallExpr(const CallExpr *E,
case Builtin::BI__builtin_popcountl:
case Builtin::BI__builtin_popcountll:
case Builtin::BI__builtin_popcountg:
case Builtin::BI__builtin_elementwise_popcount:
case Builtin::BI__popcnt16: // Microsoft variants of popcount
case Builtin::BI__popcnt:
case Builtin::BI__popcnt64: {
Expand Down
10 changes: 4 additions & 6 deletions clang/test/CodeGen/builtins-elementwise-math.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -666,11 +666,9 @@ void test_builtin_elementwise_log2(float f1, float f2, double d1, double d2,
vf2 = __builtin_elementwise_log2(vf1);
}

void test_builtin_elementwise_popcount(si8 vi1, si8 vi2,
long long int i1, long long int i2, short si,
_BitInt(31) bi1, _BitInt(31) bi2) {


void test_builtin_elementwise_popcount(si8 vi1, si8 vi2, long long int i1,
long long int i2, short si,
_BitInt(31) bi1, _BitInt(31) bi2) {
// CHECK: [[I1:%.+]] = load i64, ptr %i1.addr, align 8
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Did the IR change for the whole function?
Could you please reflect that in the new checks instead of simply removing the old checks?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Sorry for my carelessness. Only one line is actually affected. Done.

// CHECK-NEXT: call i64 @llvm.ctpop.i64(i64 [[I1]])
i2 = __builtin_elementwise_popcount(i1);
Expand All @@ -693,7 +691,7 @@ void test_builtin_elementwise_popcount(si8 vi1, si8 vi2,
// CHECK-NEXT: call i32 @llvm.ctpop.i32(i32 [[IA1]])
b = __builtin_elementwise_popcount(int_as_one);

// CHECK: call i32 @llvm.ctpop.i32(i32 -10)
// CHECK: store i32 30, ptr @b, align 4
b = __builtin_elementwise_popcount(-10);

// CHECK: [[SI:%.+]] = load i16, ptr %si.addr, align 2
Expand Down
20 changes: 20 additions & 0 deletions clang/test/Sema/constant_builtins_vector.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -797,3 +797,23 @@ static_assert(__builtin_reduce_xor((vector4int){(int)0x11111111, (int)0x22222222
static_assert(__builtin_reduce_xor((vector4long){(long long)0x1111111111111111L, (long long)0x2222222222222222L, (long long)0x4444444444444444L, (long long)0x8888888888888888L}) == (long long)0xFFFFFFFFFFFFFFFFL);
static_assert(__builtin_reduce_xor((vector4uint){0x11111111U, 0x22222222U, 0x44444444U, 0x88888888U}) == 0xFFFFFFFFU);
static_assert(__builtin_reduce_xor((vector4ulong){0x1111111111111111UL, 0x2222222222222222UL, 0x4444444444444444UL, 0x8888888888888888UL}) == 0xFFFFFFFFFFFFFFFFUL);

static_assert(__builtin_bit_cast(unsigned, __builtin_elementwise_popcount((vector4char){1, 2, 3, 4})) == (LITTLE_END ? 0x01020101 : 0x01010201));
static_assert(__builtin_bit_cast(unsigned long long, __builtin_elementwise_popcount((vector4short){0, 0x0F0F, ~0, ~0x0F0F})) == (LITTLE_END ? 0x0008001000080000 : 0x0000000800100008));
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4int){1, 2, 3, 4})) == 5);
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Could you please also add a test checking vector result but without using __builtin_reduce_add ?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Added two of them.

static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4int){0, 0xF0F0, ~0, ~0xF0F0})) == 16 * sizeof(int));
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4long){1L, 2L, 3L, 4L})) == 5L);
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4long){0L, 0xF0F0L, ~0L, ~0xF0F0L})) == 16 * sizeof(long long));
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

please can you add unsigned test coverage as well

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Done.

static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4uint){1U, 2U, 3U, 4U})) == 5U);
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4uint){0U, 0xF0F0U, ~0U, ~0xF0F0U})) == 16 * sizeof(int));
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4ulong){1UL, 2UL, 3UL, 4UL})) == 5UL);
static_assert(__builtin_reduce_add(__builtin_elementwise_popcount((vector4ulong){0ULL, 0xF0F0ULL, ~0ULL, ~0xF0F0ULL})) == 16 * sizeof(unsigned long long));
static_assert(__builtin_elementwise_popcount(0) == 0);
static_assert(__builtin_elementwise_popcount(0xF0F0) == 8);
static_assert(__builtin_elementwise_popcount(~0) == 8 * sizeof(int));
static_assert(__builtin_elementwise_popcount(0U) == 0);
static_assert(__builtin_elementwise_popcount(0xF0F0U) == 8);
static_assert(__builtin_elementwise_popcount(~0U) == 8 * sizeof(int));
static_assert(__builtin_elementwise_popcount(0L) == 0);
static_assert(__builtin_elementwise_popcount(0xF0F0L) == 8);
static_assert(__builtin_elementwise_popcount(~0LL) == 8 * sizeof(long long));
Loading