[Clang][Sema]Choose a better candidate in overload function call if there is a compatible vector conversion instead of ambiguous call error
There are 2 function variations with vector type parameter. When we call them with argument of different vector type we would prefer to
choose the variation with implicit argument conversion of compatible vector type instead of incompatible vector type. For example,
typedef float __v4sf __attribute__((__vector_size__(16)));
void f(vector float);
void f(vector signed int);
int main {
__v4sf a;
f(a);
}
Here, we'd like to choose f(vector float) but not report an ambiguous call error.
Differential revision: https://reviews.llvm.org/D53417
llvm-svn: 347019
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 3466da6..ba4b67a 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -3900,6 +3900,31 @@
S.Context.getTypeSize(SCS1.getToType(2)))
return ImplicitConversionSequence::Better;
+ // Prefer a compatible vector conversion over a lax vector conversion
+ // For example:
+ //
+ // typedef float __v4sf __attribute__((__vector_size__(16)));
+ // void f(vector float);
+ // void f(vector signed int);
+ // int main() {
+ // __v4sf a;
+ // f(a);
+ // }
+ // Here, we'd like to choose f(vector float) and not
+ // report an ambiguous call error
+ if (SCS1.Second == ICK_Vector_Conversion &&
+ SCS2.Second == ICK_Vector_Conversion) {
+ bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
+ SCS1.getFromType(), SCS1.getToType(2));
+ bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
+ SCS2.getFromType(), SCS2.getToType(2));
+
+ if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
+ return SCS1IsCompatibleVectorConversion
+ ? ImplicitConversionSequence::Better
+ : ImplicitConversionSequence::Worse;
+ }
+
return ImplicitConversionSequence::Indistinguishable;
}