[clang] Update typechecking of builtin elementwise ternary math operators

[ckoparkar]

Fixes #155405

For scalars we directly compare their unqualified types. But even if we compare unqualified vector types, a difference in qualifiers in the element types can make the vector types be considered not equal. For example, vector of 4 'const float' values vs vector of 4 'float' values. So we compare unqualified types of their elements and number of elements.

/cc @tbaederr

[llvmbot]

@llvm/pr-subscribers-clang

Author: Chaitanya Koparkar (ckoparkar)

Changes

Fixes #155405

For scalars we directly compare their unqualified types. But even if we compare unqualified vector types, a difference in qualifiers in the element types can make the vector types be considered not equal. For example, vector of 4 'const float' values vs vector of 4 'float' values. So we compare unqualified types of their elements and number of elements.

/cc @tbaederr

---

Full diff: https://github.com/llvm/llvm-project/pull/155620.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaChecking.cpp (+57-12)
• (modified) clang/test/Sema/builtins-elementwise-math.c (+19-2)

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 908ac31c6ac98..8ce308fd120e8 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -15884,6 +15884,58 @@ static bool checkBuiltinVectorMathMixedEnums(Sema &S, Expr *LHS, Expr *RHS, return false; } +/// Check if all arguments have the same type. If the types don't match, emit an +/// error message and return true. Otherwise return false. +/// +/// For scalars we directly compare their unqualified types. But even if we +/// compare unqualified vector types, a difference in qualifiers in the element +/// types can make the vector types be considered not equal. For example, +/// vector of 4 'const float' values vs vector of 4 'float' values. +/// So we compare unqualified types of their elements and number of elements. +/// See GitHub issue #155405. +static bool checkBuiltinVectorMathArgTypes(Sema &SemaRef, unsigned NumArgs, + Expr *Args[]) { + assert(NumArgs > 0 && "Should have at least one argument."); + + auto EmitError = [&](int I) { + SemaRef.Diag(Args[0]->getBeginLoc(), + diag::err_typecheck_call_different_arg_types) + << Args[0]->getType() << Args[I]->getType(); + }; + + QualType Ty0 = Args[0]->getType(); + + // Compare scalar types. + if (!Ty0->isVectorType()) { + for (unsigned I = 1; I < NumArgs; ++I) + if (!SemaRef.Context.hasSameUnqualifiedType(Ty0, Args[I]->getType())) { + EmitError(I); + return true; + } + + return false; + } + + // Compare vector types. + const auto *Vec0 = Ty0->castAs<VectorType>(); + for (unsigned I = 1; I < NumArgs; ++I) { + QualType TyI = Args[I]->getType(); + if (!TyI->isVectorType()) { + EmitError(I); + return true; + } + const auto *VecI = TyI->castAs<VectorType>(); + if (!SemaRef.Context.hasSameUnqualifiedType(Vec0->getElementType(), + VecI->getElementType()) || + Vec0->getNumElements() != VecI->getNumElements()) { + EmitError(I); + return true; + } + } + + return false; +} + std::optional<QualType> Sema::BuiltinVectorMath(CallExpr *TheCall, EltwiseBuiltinArgTyRestriction ArgTyRestr) { @@ -15905,13 +15957,11 @@ Sema::BuiltinVectorMath(CallExpr *TheCall, SourceLocation LocA = Args[0]->getBeginLoc(); QualType TyA = Args[0]->getType(); - QualType TyB = Args[1]->getType(); if (checkMathBuiltinElementType(*this, LocA, TyA, ArgTyRestr, 1)) return std::nullopt; - if (!Context.hasSameUnqualifiedType(TyA, TyB)) { - Diag(LocA, diag::err_typecheck_call_different_arg_types) << TyA << TyB; + if (checkBuiltinVectorMathArgTypes(*this, 2, Args)) { return std::nullopt; } @@ -15948,17 +15998,12 @@ bool Sema::BuiltinElementwiseTernaryMath( return true; } - TheCall->setArg(0, Args[0]); - for (int I = 1; I < 3; ++I) { - if (Args[0]->getType().getCanonicalType() != - Args[I]->getType().getCanonicalType()) { - return Diag(Args[0]->getBeginLoc(), - diag::err_typecheck_call_different_arg_types) - << Args[0]->getType() << Args[I]->getType(); - } + if (checkBuiltinVectorMathArgTypes(*this, 3, Args)) { + return true; + } + for (int I = 0; I < 3; ++I) TheCall->setArg(I, Args[I]); - } TheCall->setType(Args[0]->getType()); return false; diff --git a/clang/test/Sema/builtins-elementwise-math.c b/clang/test/Sema/builtins-elementwise-math.c index 02dd44211e96a..d6ce5c0a34746 100644 --- a/clang/test/Sema/builtins-elementwise-math.c +++ b/clang/test/Sema/builtins-elementwise-math.c @@ -5,6 +5,7 @@ typedef double double4 __attribute__((ext_vector_type(4))); typedef float float2 __attribute__((ext_vector_type(2))); typedef float float3 __attribute__((ext_vector_type(3))); typedef float float4 __attribute__((ext_vector_type(4))); +typedef const float cfloat4 __attribute__((ext_vector_type(4))); typedef int int2 __attribute__((ext_vector_type(2))); typedef int int3 __attribute__((ext_vector_type(3))); @@ -1330,16 +1331,32 @@ void test_builtin_elementwise_fsh(int i32, int2 v2i32, short i16, int3 v3i32, // expected-error@-1 {{arguments are of different types ('int3' (vector of 3 'int' values) vs 'int2' (vector of 2 'int' values))}} } +// Tests corresponding to GitHub issues #141397 and #155405. +// Type mismatch error when 'builtin-elementwise-math' arguments have +// different qualifiers, this should be well-formed. typedef struct { float3 b; } struct_float3; -// This example uncovered a bug #141397 : -// Type mismatch error when 'builtin-elementwise-math' arguments have different qualifiers, this should be well-formed + float3 foo(float3 a,const struct_float3* hi) { float3 b = __builtin_elementwise_max((float3)(0.0f), a); return __builtin_elementwise_pow(b, hi->b.yyy); } +float3 baz(float3 a, const struct_float3* hi) { + return __builtin_elementwise_fma(a, a, hi->b); +} + +cfloat4 qux(cfloat4 x, float4 y, float4 z) { + float a = __builtin_elementwise_fma(x[0],y[0],z[0]); + return __builtin_elementwise_fma(x,y,z); +} + +cfloat4 quux(cfloat4 x, float4 y) { + float a = __builtin_elementwise_pow(x[0],y[0]); + return __builtin_elementwise_pow(x,y); +} + void test_builtin_elementwise_ctlz(int i32, int2 v2i32, short i16, double f64, double2 v2f64) { f64 = __builtin_elementwise_ctlz(f64); 

[ckoparkar]

• This patch only changes the behavior for input arguments. For consistency, we should change how canonical types are computed for these vectors, but that will have a widespread impact.

[Sirraide]

This still needs a release note.

[ckoparkar]

Thanks everyone for reviewing :-)