[clang] [Clang] Add vector gather / scatter builtins to clang (PR #157895)
Joseph Huber via cfe-commits
cfe-commits at lists.llvm.org
Fri Sep 12 17:38:18 PDT 2025
https://github.com/jhuber6 updated https://github.com/llvm/llvm-project/pull/157895
>From 105d21ef27d1993527924e1da5f181dc9a67eff1 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Wed, 10 Sep 2025 11:41:25 -0500
Subject: [PATCH 1/3] [Clang] Add vector gather / scatter builtins to clang
Summary:
This patch exposes `__builtin_masked_gather` and
`__builtin_masked_scatter` to clang. These map to the underlying
intrinsic relatively cleanly, needing only a level of indirection to
take a vector of indices and a base pointer to a vector of pointers.
---
clang/docs/LanguageExtensions.rst | 13 ++++
clang/docs/ReleaseNotes.rst | 4 +
clang/include/clang/Basic/Builtins.td | 12 +++
clang/lib/CodeGen/CGBuiltin.cpp | 41 ++++++++++
clang/lib/Sema/SemaChecking.cpp | 107 +++++++++++++++++++++++++-
clang/test/CodeGen/builtin-masked.c | 58 ++++++++++++++
clang/test/Sema/builtin-masked.c | 20 +++++
7 files changed, 252 insertions(+), 3 deletions(-)
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst
index ad190eace5b05..f3ce5ee534609 100644
--- a/clang/docs/LanguageExtensions.rst
+++ b/clang/docs/LanguageExtensions.rst
@@ -957,6 +957,11 @@ builtins have the same interface but store the result in consecutive indices.
Effectively this performs the ``if (mask[i]) val[i] = ptr[j++]`` and ``if
(mask[i]) ptr[j++] = val[i]`` pattern respectively.
+The ``__builtin_masked_gather`` and ``__builtin_masked_scatter`` builtins handle
+non-sequential memory access for vector types. These use a base pointer and a
+vector of integer indices to gather memory into a vector type or scatter it to
+separate indices.
+
Example:
.. code-block:: c++
@@ -978,6 +983,14 @@ Example:
__builtin_masked_compress_store(mask, val, ptr);
}
+ v8i gather(v8b mask, v8i idx, int *ptr) {
+ return __builtin_masked_gather(mask, idx, ptr);
+ }
+
+ void scatter(v8b mask, v8i val, v8i idx, int *ptr) {
+ __builtin_masked_scatter(mask, idx, val, ptr);
+ }
+
Matrix Types
============
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e1e497ccdbccd..4a68688540ddb 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -183,6 +183,10 @@ Non-comprehensive list of changes in this release
conditional memory loads from vectors. Binds to the LLVM intrinsics of the
same name.
+- Added ``__builtin_masked_gather`` and ``__builtin_masked_scatter`` for
+ conditional gathering and scattering operations on vectors. Binds to the LLVM
+ intrinsics of the same name.
+
- The ``__builtin_popcountg``, ``__builtin_ctzg``, and ``__builtin_clzg``
functions now accept fixed-size boolean vectors.
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 27639f06529cb..97be087aa752a 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -1256,6 +1256,18 @@ def MaskedCompressStore : Builtin {
let Prototype = "void(...)";
}
+def MaskedGather : Builtin {
+ let Spellings = ["__builtin_masked_gather"];
+ let Attributes = [NoThrow, CustomTypeChecking];
+ let Prototype = "void(...)";
+}
+
+def MaskedScatter : Builtin {
+ let Spellings = ["__builtin_masked_scatter"];
+ let Attributes = [NoThrow, CustomTypeChecking];
+ let Prototype = "void(...)";
+}
+
def AllocaUninitialized : Builtin {
let Spellings = ["__builtin_alloca_uninitialized"];
let Attributes = [FunctionWithBuiltinPrefix, NoThrow];
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 172a521e63c17..ef50ba8328bfd 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -4298,6 +4298,30 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
}
return RValue::get(Result);
};
+ case Builtin::BI__builtin_masked_gather: {
+ llvm::Value *Mask = EmitScalarExpr(E->getArg(0));
+ llvm::Value *Idx = EmitScalarExpr(E->getArg(1));
+ llvm::Value *Ptr = EmitScalarExpr(E->getArg(2));
+
+ llvm::Type *RetTy = CGM.getTypes().ConvertType(E->getType());
+ llvm::Type *ElemTy = CGM.getTypes().ConvertType(
+ E->getType()->getAs<VectorType>()->getElementType());
+ llvm::Value *AlignVal = llvm::ConstantInt::get(Int32Ty, 1);
+
+ llvm::Value *PassThru = llvm::PoisonValue::get(RetTy);
+ if (E->getNumArgs() > 3)
+ PassThru = EmitScalarExpr(E->getArg(3));
+
+ llvm::Value *PtrVec = Builder.CreateGEP(ElemTy, Ptr, Idx);
+
+ llvm::Value *Result;
+ Function *F =
+ CGM.getIntrinsic(Intrinsic::masked_gather, {RetTy, PtrVec->getType()});
+
+ Result = Builder.CreateCall(F, {PtrVec, AlignVal, Mask, PassThru},
+ "masked_gather");
+ return RValue::get(Result);
+ }
case Builtin::BI__builtin_masked_store:
case Builtin::BI__builtin_masked_compress_store: {
llvm::Value *Mask = EmitScalarExpr(E->getArg(0));
@@ -4323,7 +4347,24 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
}
return RValue::get(nullptr);
}
+ case Builtin::BI__builtin_masked_scatter: {
+ llvm::Value *Mask = EmitScalarExpr(E->getArg(0));
+ llvm::Value *Val = EmitScalarExpr(E->getArg(1));
+ llvm::Value *Idx = EmitScalarExpr(E->getArg(2));
+ llvm::Value *Ptr = EmitScalarExpr(E->getArg(3));
+ llvm::Type *ElemTy = CGM.getTypes().ConvertType(
+ E->getArg(1)->getType()->getAs<VectorType>()->getElementType());
+ llvm::Value *AlignVal = llvm::ConstantInt::get(Int32Ty, 1);
+
+ llvm::Value *PtrVec = Builder.CreateGEP(ElemTy, Ptr, Idx);
+
+ Function *F = CGM.getIntrinsic(Intrinsic::masked_scatter,
+ {Val->getType(), PtrVec->getType()});
+
+ Builder.CreateCall(F, {Val, PtrVec, AlignVal, Mask});
+ return RValue();
+ }
case Builtin::BI__builtin_isinf_sign: {
// isinf_sign(x) -> fabs(x) == infinity ? (signbit(x) ? -1 : 1) : 0
CodeGenFunction::CGFPOptionsRAII FPOptsRAII(*this, E);
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 077f4311ed729..6634f38182e41 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2270,7 +2270,7 @@ static bool BuiltinCountZeroBitsGeneric(Sema &S, CallExpr *TheCall) {
}
static bool CheckMaskedBuiltinArgs(Sema &S, Expr *MaskArg, Expr *PtrArg,
- unsigned Pos) {
+ unsigned Pos, bool Vector = true) {
QualType MaskTy = MaskArg->getType();
if (!MaskTy->isExtVectorBoolType())
return S.Diag(MaskArg->getBeginLoc(), diag::err_builtin_invalid_arg_type)
@@ -2278,9 +2278,11 @@ static bool CheckMaskedBuiltinArgs(Sema &S, Expr *MaskArg, Expr *PtrArg,
<< MaskTy;
QualType PtrTy = PtrArg->getType();
- if (!PtrTy->isPointerType() || !PtrTy->getPointeeType()->isVectorType())
+ if (!PtrTy->isPointerType() ||
+ (Vector && !PtrTy->getPointeeType()->isVectorType()) ||
+ (!Vector && PtrTy->getPointeeType()->isVectorType()))
return S.Diag(PtrArg->getExprLoc(), diag::err_vec_masked_load_store_ptr)
- << Pos << "pointer to vector";
+ << Pos << (Vector ? "pointer to vector" : "scalar pointer");
return false;
}
@@ -2361,6 +2363,101 @@ static ExprResult BuiltinMaskedStore(Sema &S, CallExpr *TheCall) {
return TheCall;
}
+static ExprResult BuiltinMaskedGather(Sema &S, CallExpr *TheCall) {
+ if (S.checkArgCountRange(TheCall, 3, 4))
+ return ExprError();
+
+ Expr *MaskArg = TheCall->getArg(0);
+ Expr *IdxArg = TheCall->getArg(1);
+ Expr *PtrArg = TheCall->getArg(2);
+ if (CheckMaskedBuiltinArgs(S, MaskArg, PtrArg, 3, /*Vector=*/false))
+ return ExprError();
+
+ QualType IdxTy = IdxArg->getType();
+ const VectorType *IdxVecTy = IdxTy->getAs<VectorType>();
+ if (!IdxTy->isExtVectorType() || !IdxVecTy->getElementType()->isIntegerType())
+ return S.Diag(MaskArg->getBeginLoc(), diag::err_builtin_invalid_arg_type)
+ << 1 << /* vector of */ 4 << /* integer */ 1 << /* no fp */ 0
+ << IdxTy;
+
+ QualType MaskTy = MaskArg->getType();
+ QualType PtrTy = PtrArg->getType();
+ QualType PointeeTy = PtrTy->getPointeeType();
+ const VectorType *MaskVecTy = MaskTy->getAs<VectorType>();
+ if (MaskVecTy->getNumElements() != IdxVecTy->getNumElements())
+ return ExprError(
+ S.Diag(TheCall->getBeginLoc(), diag::err_vec_masked_load_store_size)
+ << S.getASTContext().BuiltinInfo.getQuotedName(
+ TheCall->getBuiltinCallee())
+ << MaskTy << IdxTy);
+
+ QualType RetTy =
+ S.Context.getExtVectorType(PointeeTy, MaskVecTy->getNumElements());
+ if (TheCall->getNumArgs() == 4) {
+ Expr *PassThruArg = TheCall->getArg(3);
+ QualType PassThruTy = PassThruArg->getType();
+ if (!S.Context.hasSameType(PassThruTy, RetTy))
+ return S.Diag(PassThruArg->getExprLoc(),
+ diag::err_vec_masked_load_store_ptr)
+ << /* fourth argument */ 4 << RetTy;
+ }
+
+ TheCall->setType(RetTy);
+ return TheCall;
+}
+
+static ExprResult BuiltinMaskedScatter(Sema &S, CallExpr *TheCall) {
+ if (S.checkArgCount(TheCall, 4))
+ return ExprError();
+
+ Expr *MaskArg = TheCall->getArg(0);
+ Expr *IdxArg = TheCall->getArg(1);
+ Expr *ValArg = TheCall->getArg(2);
+ Expr *PtrArg = TheCall->getArg(3);
+
+ if (CheckMaskedBuiltinArgs(S, MaskArg, PtrArg, 3, /*Vector=*/false))
+ return ExprError();
+
+ QualType IdxTy = IdxArg->getType();
+ const VectorType *IdxVecTy = IdxTy->getAs<VectorType>();
+ if (!IdxTy->isExtVectorType() || !IdxVecTy->getElementType()->isIntegerType())
+ return S.Diag(MaskArg->getBeginLoc(), diag::err_builtin_invalid_arg_type)
+ << 2 << /* vector of */ 4 << /* integer */ 1 << /* no fp */ 0
+ << IdxTy;
+
+ QualType ValTy = ValArg->getType();
+ QualType MaskTy = MaskArg->getType();
+ QualType PtrTy = PtrArg->getType();
+ QualType PointeeTy = PtrTy->getPointeeType();
+
+ const VectorType *MaskVecTy = MaskTy->getAs<VectorType>();
+ const VectorType *ValVecTy = ValTy->getAs<VectorType>();
+ if (MaskVecTy->getNumElements() != IdxVecTy->getNumElements())
+ return ExprError(
+ S.Diag(TheCall->getBeginLoc(), diag::err_vec_masked_load_store_size)
+ << S.getASTContext().BuiltinInfo.getQuotedName(
+ TheCall->getBuiltinCallee())
+ << MaskTy << IdxTy);
+ if (MaskVecTy->getNumElements() != ValVecTy->getNumElements())
+ return ExprError(
+ S.Diag(TheCall->getBeginLoc(), diag::err_vec_masked_load_store_size)
+ << S.getASTContext().BuiltinInfo.getQuotedName(
+ TheCall->getBuiltinCallee())
+ << MaskTy << ValTy);
+
+ QualType ArgTy =
+ S.Context.getExtVectorType(PointeeTy, MaskVecTy->getNumElements());
+ if (!S.Context.hasSameType(ValTy, ArgTy))
+ return ExprError(S.Diag(TheCall->getBeginLoc(),
+ diag::err_vec_builtin_incompatible_vector)
+ << TheCall->getDirectCallee() << /*isMorethantwoArgs*/ 2
+ << SourceRange(TheCall->getArg(1)->getBeginLoc(),
+ TheCall->getArg(1)->getEndLoc()));
+
+ TheCall->setType(S.Context.VoidTy);
+ return TheCall;
+}
+
static ExprResult BuiltinInvoke(Sema &S, CallExpr *TheCall) {
SourceLocation Loc = TheCall->getBeginLoc();
MutableArrayRef Args(TheCall->getArgs(), TheCall->getNumArgs());
@@ -2619,6 +2716,10 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
case Builtin::BI__builtin_masked_store:
case Builtin::BI__builtin_masked_compress_store:
return BuiltinMaskedStore(*this, TheCall);
+ case Builtin::BI__builtin_masked_gather:
+ return BuiltinMaskedGather(*this, TheCall);
+ case Builtin::BI__builtin_masked_scatter:
+ return BuiltinMaskedScatter(*this, TheCall);
case Builtin::BI__builtin_invoke:
return BuiltinInvoke(*this, TheCall);
case Builtin::BI__builtin_prefetch:
diff --git a/clang/test/CodeGen/builtin-masked.c b/clang/test/CodeGen/builtin-masked.c
index 579cf5c413c9b..66e6d10f1f3b1 100644
--- a/clang/test/CodeGen/builtin-masked.c
+++ b/clang/test/CodeGen/builtin-masked.c
@@ -129,3 +129,61 @@ void test_store(v8b m, v8i v, v8i *p) {
void test_compress_store(v8b m, v8i v, v8i *p) {
__builtin_masked_compress_store(m, v, p);
}
+
+// CHECK-LABEL: define dso_local <8 x i32> @test_gather(
+// CHECK-SAME: i8 noundef [[MASK_COERCE:%.*]], ptr noundef byval(<8 x i32>) align 32 [[TMP0:%.*]], ptr noundef [[PTR:%.*]]) #[[ATTR0]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[MASK:%.*]] = alloca i8, align 1
+// CHECK-NEXT: [[MASK_ADDR:%.*]] = alloca i8, align 1
+// CHECK-NEXT: [[IDX_ADDR:%.*]] = alloca <8 x i32>, align 32
+// CHECK-NEXT: [[PTR_ADDR:%.*]] = alloca ptr, align 8
+// CHECK-NEXT: store i8 [[MASK_COERCE]], ptr [[MASK]], align 1
+// CHECK-NEXT: [[LOAD_BITS:%.*]] = load i8, ptr [[MASK]], align 1
+// CHECK-NEXT: [[MASK1:%.*]] = bitcast i8 [[LOAD_BITS]] to <8 x i1>
+// CHECK-NEXT: [[IDX:%.*]] = load <8 x i32>, ptr [[TMP0]], align 32
+// CHECK-NEXT: [[TMP1:%.*]] = bitcast <8 x i1> [[MASK1]] to i8
+// CHECK-NEXT: store i8 [[TMP1]], ptr [[MASK_ADDR]], align 1
+// CHECK-NEXT: store <8 x i32> [[IDX]], ptr [[IDX_ADDR]], align 32
+// CHECK-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8
+// CHECK-NEXT: [[LOAD_BITS2:%.*]] = load i8, ptr [[MASK_ADDR]], align 1
+// CHECK-NEXT: [[TMP2:%.*]] = bitcast i8 [[LOAD_BITS2]] to <8 x i1>
+// CHECK-NEXT: [[TMP3:%.*]] = load <8 x i32>, ptr [[IDX_ADDR]], align 32
+// CHECK-NEXT: [[TMP4:%.*]] = load ptr, ptr [[PTR_ADDR]], align 8
+// CHECK-NEXT: [[TMP5:%.*]] = getelementptr i32, ptr [[TMP4]], <8 x i32> [[TMP3]]
+// CHECK-NEXT: [[MASKED_GATHER:%.*]] = call <8 x i32> @llvm.masked.gather.v8i32.v8p0(<8 x ptr> [[TMP5]], i32 1, <8 x i1> [[TMP2]], <8 x i32> poison)
+// CHECK-NEXT: ret <8 x i32> [[MASKED_GATHER]]
+//
+v8i test_gather(v8b mask, v8i idx, int *ptr) {
+ return __builtin_masked_gather(mask, idx, ptr);
+}
+
+// CHECK-LABEL: define dso_local void @test_scatter(
+// CHECK-SAME: i8 noundef [[MASK_COERCE:%.*]], ptr noundef byval(<8 x i32>) align 32 [[TMP0:%.*]], ptr noundef byval(<8 x i32>) align 32 [[TMP1:%.*]], ptr noundef [[PTR:%.*]]) #[[ATTR3]] {
+// CHECK-NEXT: [[ENTRY:.*:]]
+// CHECK-NEXT: [[MASK:%.*]] = alloca i8, align 1
+// CHECK-NEXT: [[MASK_ADDR:%.*]] = alloca i8, align 1
+// CHECK-NEXT: [[VAL_ADDR:%.*]] = alloca <8 x i32>, align 32
+// CHECK-NEXT: [[IDX_ADDR:%.*]] = alloca <8 x i32>, align 32
+// CHECK-NEXT: [[PTR_ADDR:%.*]] = alloca ptr, align 8
+// CHECK-NEXT: store i8 [[MASK_COERCE]], ptr [[MASK]], align 1
+// CHECK-NEXT: [[LOAD_BITS:%.*]] = load i8, ptr [[MASK]], align 1
+// CHECK-NEXT: [[MASK1:%.*]] = bitcast i8 [[LOAD_BITS]] to <8 x i1>
+// CHECK-NEXT: [[VAL:%.*]] = load <8 x i32>, ptr [[TMP0]], align 32
+// CHECK-NEXT: [[IDX:%.*]] = load <8 x i32>, ptr [[TMP1]], align 32
+// CHECK-NEXT: [[TMP2:%.*]] = bitcast <8 x i1> [[MASK1]] to i8
+// CHECK-NEXT: store i8 [[TMP2]], ptr [[MASK_ADDR]], align 1
+// CHECK-NEXT: store <8 x i32> [[VAL]], ptr [[VAL_ADDR]], align 32
+// CHECK-NEXT: store <8 x i32> [[IDX]], ptr [[IDX_ADDR]], align 32
+// CHECK-NEXT: store ptr [[PTR]], ptr [[PTR_ADDR]], align 8
+// CHECK-NEXT: [[LOAD_BITS2:%.*]] = load i8, ptr [[MASK_ADDR]], align 1
+// CHECK-NEXT: [[TMP3:%.*]] = bitcast i8 [[LOAD_BITS2]] to <8 x i1>
+// CHECK-NEXT: [[TMP4:%.*]] = load <8 x i32>, ptr [[VAL_ADDR]], align 32
+// CHECK-NEXT: [[TMP5:%.*]] = load <8 x i32>, ptr [[IDX_ADDR]], align 32
+// CHECK-NEXT: [[TMP6:%.*]] = load ptr, ptr [[PTR_ADDR]], align 8
+// CHECK-NEXT: [[TMP7:%.*]] = getelementptr i32, ptr [[TMP6]], <8 x i32> [[TMP5]]
+// CHECK-NEXT: call void @llvm.masked.scatter.v8i32.v8p0(<8 x i32> [[TMP4]], <8 x ptr> [[TMP7]], i32 1, <8 x i1> [[TMP3]])
+// CHECK-NEXT: ret void
+//
+void test_scatter(v8b mask, v8i val, v8i idx, int *ptr) {
+ __builtin_masked_scatter(mask, val, idx, ptr);
+}
diff --git a/clang/test/Sema/builtin-masked.c b/clang/test/Sema/builtin-masked.c
index 05c6580651964..eb0070b0276af 100644
--- a/clang/test/Sema/builtin-masked.c
+++ b/clang/test/Sema/builtin-masked.c
@@ -44,3 +44,23 @@ void test_masked_compress_store(v8i *pf, v8f *pf2, v8b mask, v2b mask2) {
__builtin_masked_compress_store(mask2, *pf, pf); // expected-error {{all arguments to '__builtin_masked_compress_store' must have the same number of elements}}
__builtin_masked_compress_store(mask, *pf, pf2); // expected-error {{last two arguments to '__builtin_masked_compress_store' must have the same type}}
}
+
+void test_masked_gather(int *p, v8i idx, v8b mask, v2b mask2, v2b thru) {
+ __builtin_masked_gather(mask); // expected-error {{too few arguments to function call, expected 3, have 1}}
+ __builtin_masked_gather(mask, p, p, p, p, p); // expected-error {{too many arguments to function call, expected at most 4, have 6}}
+ __builtin_masked_gather(p, p, p); // expected-error {{1st argument must be a vector of boolean types (was 'int *')}}
+ __builtin_masked_gather(mask, p, p); // expected-error {{1st argument must be a vector of integer types (was 'int *')}}
+ __builtin_masked_gather(mask2, idx, p); // expected-error {{all arguments to '__builtin_masked_gather' must have the same number of elements (was 'v2b'}}
+ __builtin_masked_gather(mask, idx, p, thru); // expected-error {{4th argument must be a 'int __attribute__((ext_vector_type(8)))' (vector of 8 'int' values)}}
+ __builtin_masked_gather(mask, idx, &idx); // expected-error {{3rd argument must be a scalar pointer}}
+}
+
+void test_masked_scatter(int *p, v8i idx, v8b mask, v2b mask2, v8i val) {
+ __builtin_masked_scatter(mask); // expected-error {{too few arguments to function call, expected 4, have 1}}
+ __builtin_masked_scatter(mask, p, p, p, p, p); // expected-error {{too many arguments to function call, expected 4, have 6}}
+ __builtin_masked_scatter(p, p, p, p); // expected-error {{1st argument must be a vector of boolean types (was 'int *')}}
+ __builtin_masked_scatter(mask, p, p, p); // expected-error {{2nd argument must be a vector of integer types (was 'int *')}}
+ __builtin_masked_scatter(mask, idx, mask, p); // expected-error {{last two arguments to '__builtin_masked_scatter' must have the same type}}
+ __builtin_masked_scatter(mask, idx, val, idx); // expected-error {{3rd argument must be a scalar pointer}}
+ __builtin_masked_scatter(mask, idx, val, &idx); // expected-error {{3rd argument must be a scalar pointer}}
+}
>From 6e5fdebbbf57acfe8b14dc993abcf49ae6c12fc8 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 11 Sep 2025 08:16:47 -0500
Subject: [PATCH 2/3] Alignment
---
clang/lib/CodeGen/CGBuiltin.cpp | 21 ++++++++++++++-------
clang/test/CodeGen/builtin-masked.c | 6 +++---
2 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index ef50ba8328bfd..aa80877463a9a 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -4304,14 +4304,17 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
llvm::Value *Ptr = EmitScalarExpr(E->getArg(2));
llvm::Type *RetTy = CGM.getTypes().ConvertType(E->getType());
- llvm::Type *ElemTy = CGM.getTypes().ConvertType(
- E->getType()->getAs<VectorType>()->getElementType());
- llvm::Value *AlignVal = llvm::ConstantInt::get(Int32Ty, 1);
+ CharUnits Align = CGM.getNaturalTypeAlignment(
+ E->getType()->getAs<VectorType>()->getElementType(), nullptr);
+ llvm::Value *AlignVal =
+ llvm::ConstantInt::get(Int32Ty, Align.getQuantity());
llvm::Value *PassThru = llvm::PoisonValue::get(RetTy);
if (E->getNumArgs() > 3)
PassThru = EmitScalarExpr(E->getArg(3));
+ llvm::Type *ElemTy = CGM.getTypes().ConvertType(
+ E->getType()->getAs<VectorType>()->getElementType());
llvm::Value *PtrVec = Builder.CreateGEP(ElemTy, Ptr, Idx);
llvm::Value *Result;
@@ -4349,14 +4352,18 @@ RValue CodeGenFunction::EmitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
}
case Builtin::BI__builtin_masked_scatter: {
llvm::Value *Mask = EmitScalarExpr(E->getArg(0));
- llvm::Value *Val = EmitScalarExpr(E->getArg(1));
- llvm::Value *Idx = EmitScalarExpr(E->getArg(2));
+ llvm::Value *Idx = EmitScalarExpr(E->getArg(1));
+ llvm::Value *Val = EmitScalarExpr(E->getArg(2));
llvm::Value *Ptr = EmitScalarExpr(E->getArg(3));
+ CharUnits Align = CGM.getNaturalTypeAlignment(
+ E->getArg(2)->getType()->getAs<VectorType>()->getElementType(),
+ nullptr);
+ llvm::Value *AlignVal =
+ llvm::ConstantInt::get(Int32Ty, Align.getQuantity());
+
llvm::Type *ElemTy = CGM.getTypes().ConvertType(
E->getArg(1)->getType()->getAs<VectorType>()->getElementType());
- llvm::Value *AlignVal = llvm::ConstantInt::get(Int32Ty, 1);
-
llvm::Value *PtrVec = Builder.CreateGEP(ElemTy, Ptr, Idx);
Function *F = CGM.getIntrinsic(Intrinsic::masked_scatter,
diff --git a/clang/test/CodeGen/builtin-masked.c b/clang/test/CodeGen/builtin-masked.c
index 66e6d10f1f3b1..adb1ad4b698ac 100644
--- a/clang/test/CodeGen/builtin-masked.c
+++ b/clang/test/CodeGen/builtin-masked.c
@@ -150,7 +150,7 @@ void test_compress_store(v8b m, v8i v, v8i *p) {
// CHECK-NEXT: [[TMP3:%.*]] = load <8 x i32>, ptr [[IDX_ADDR]], align 32
// CHECK-NEXT: [[TMP4:%.*]] = load ptr, ptr [[PTR_ADDR]], align 8
// CHECK-NEXT: [[TMP5:%.*]] = getelementptr i32, ptr [[TMP4]], <8 x i32> [[TMP3]]
-// CHECK-NEXT: [[MASKED_GATHER:%.*]] = call <8 x i32> @llvm.masked.gather.v8i32.v8p0(<8 x ptr> [[TMP5]], i32 1, <8 x i1> [[TMP2]], <8 x i32> poison)
+// CHECK-NEXT: [[MASKED_GATHER:%.*]] = call <8 x i32> @llvm.masked.gather.v8i32.v8p0(<8 x ptr> [[TMP5]], i32 4, <8 x i1> [[TMP2]], <8 x i32> poison)
// CHECK-NEXT: ret <8 x i32> [[MASKED_GATHER]]
//
v8i test_gather(v8b mask, v8i idx, int *ptr) {
@@ -180,8 +180,8 @@ v8i test_gather(v8b mask, v8i idx, int *ptr) {
// CHECK-NEXT: [[TMP4:%.*]] = load <8 x i32>, ptr [[VAL_ADDR]], align 32
// CHECK-NEXT: [[TMP5:%.*]] = load <8 x i32>, ptr [[IDX_ADDR]], align 32
// CHECK-NEXT: [[TMP6:%.*]] = load ptr, ptr [[PTR_ADDR]], align 8
-// CHECK-NEXT: [[TMP7:%.*]] = getelementptr i32, ptr [[TMP6]], <8 x i32> [[TMP5]]
-// CHECK-NEXT: call void @llvm.masked.scatter.v8i32.v8p0(<8 x i32> [[TMP4]], <8 x ptr> [[TMP7]], i32 1, <8 x i1> [[TMP3]])
+// CHECK-NEXT: [[TMP7:%.*]] = getelementptr i32, ptr [[TMP6]], <8 x i32> [[TMP4]]
+// CHECK-NEXT: call void @llvm.masked.scatter.v8i32.v8p0(<8 x i32> [[TMP5]], <8 x ptr> [[TMP7]], i32 4, <8 x i1> [[TMP3]])
// CHECK-NEXT: ret void
//
void test_scatter(v8b mask, v8i val, v8i idx, int *ptr) {
>From b64ba3af9bdea040aed254019ea9e4dfec07b4bc Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Fri, 12 Sep 2025 07:42:17 -0500
Subject: [PATCH 3/3] Pure
---
clang/include/clang/Basic/Builtins.td | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
index 97be087aa752a..218d27a010ff4 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -1258,7 +1258,7 @@ def MaskedCompressStore : Builtin {
def MaskedGather : Builtin {
let Spellings = ["__builtin_masked_gather"];
- let Attributes = [NoThrow, CustomTypeChecking];
+ let Attributes = [NoThrow, Pure, CustomTypeChecking];
let Prototype = "void(...)";
}
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