C++: Support more complex 16-bit float types

cpp/downgrades/7bc12b02a4363149f0727a4bce07952dbb9d98aa/builtintypes.ql

@@ -0,0 +1,14 @@
+class BuiltinType extends @builtintype {
+  string toString() { none() }
+}
+
+from BuiltinType type, string name, int kind, int kind_new, int size, int sign, int alignment
+where
+  builtintypes(type, name, kind, size, sign, alignment) and
+  if
+    type instanceof @complex_fp16 or
+    type instanceof @complex_std_bfloat16 or
+    type instanceof @complex_std_float16
+  then kind_new = 2
+  else kind_new = kind
+select type, name, kind_new, size, sign, alignment

cpp/downgrades/7bc12b02a4363149f0727a4bce07952dbb9d98aa/upgrade.properties

@@ -0,0 +1,3 @@
+description: Introduce new complex 16-bit floating-point types
+compatibility: backwards
+builtintypes.rel: run builtintypes.qlo

cpp/ql/lib/change-notes/2025-06-24-float16.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Added support for `__fp16 _Complex` and `__bf16 _Complex` types

cpp/ql/lib/semmle/code/cpp/Type.qll

@@ -858,6 +858,15 @@ private predicate floatingPointTypeMapping(
   or
   // __mfp8
   kind = 62 and base = 2 and domain = TRealDomain() and realKind = 62 and extended = false
+  or
+  // _Complex __fp16
+  kind = 64 and base = 2 and domain = TComplexDomain() and realKind = 54 and extended = false
+  or
+  // _Complex __bf16
+  kind = 65 and base = 2 and domain = TComplexDomain() and realKind = 55 and extended = false
+  or
+  // _Complex std::float16_t
+  kind = 66 and base = 2 and domain = TComplexDomain() and realKind = 56 and extended = false
 }
 
 /**

cpp/ql/lib/semmlecode.cpp.dbscheme

@@ -693,6 +693,9 @@ case @builtintype.kind of
 | 61 = @complex_std_float128  // _Complex _Float128
 | 62 = @mfp8                  // __mfp8
 | 63 = @scalable_vector_count // __SVCount_t
+| 64 = @complex_fp16          // _Complex __fp16
+| 65 = @complex_std_bfloat16  // _Complex __bf16
+| 66 = @complex_std_float16   // _Complex std::float16_t
 ;
 
 builtintypes(

cpp/ql/lib/semmlecode.cpp.dbscheme.stats

@@ -336,6 +336,18 @@
             <k>@scalable_vector_count</k>
             <v>124</v>
         </e>
+        <e>
+            <k>@complex_fp16</k>
+            <v>124</v>
+        </e>
+        <e>
+            <k>@complex_std_bfloat16</k>
+            <v>124</v>
+        </e>
+        <e>
+            <k>@complex_std_float16</k>
+            <v>124</v>
+        </e>
         <e>
             <k>@pointer</k>
             <v>455609</v>

cpp/ql/lib/upgrades/e38346051783182ea75822e4adf8d4c6a949bc37/upgrade.properties

@@ -0,0 +1,2 @@
+description: Support more complex 16-bit floating-point types
+compatibility: full

cpp/ql/test/library-tests/templates/type_instantiations/types.expected

@@ -5,10 +5,13 @@
 | file://:0:0:0:0 | _Complex _Float64 |
 | file://:0:0:0:0 | _Complex _Float64x |
 | file://:0:0:0:0 | _Complex _Float128 |
+| file://:0:0:0:0 | _Complex __bf16 |
 | file://:0:0:0:0 | _Complex __float128 |
+| file://:0:0:0:0 | _Complex __fp16 |
 | file://:0:0:0:0 | _Complex double |
 | file://:0:0:0:0 | _Complex float |
 | file://:0:0:0:0 | _Complex long double |
+| file://:0:0:0:0 | _Complex std::float16_t |
 | file://:0:0:0:0 | _Decimal32 |
 | file://:0:0:0:0 | _Decimal64 |
 | file://:0:0:0:0 | _Decimal128 |

cpp/ql/test/library-tests/type_sizes/type_sizes.expected

@@ -25,10 +25,13 @@
 | file://:0:0:0:0 | _Complex _Float64 | 16 |
 | file://:0:0:0:0 | _Complex _Float64x | 32 |
 | file://:0:0:0:0 | _Complex _Float128 | 32 |
+| file://:0:0:0:0 | _Complex __bf16 | 4 |
 | file://:0:0:0:0 | _Complex __float128 | 32 |
+| file://:0:0:0:0 | _Complex __fp16 | 4 |
 | file://:0:0:0:0 | _Complex double | 16 |
 | file://:0:0:0:0 | _Complex float | 8 |
 | file://:0:0:0:0 | _Complex long double | 32 |
+| file://:0:0:0:0 | _Complex std::float16_t | 4 |
 | file://:0:0:0:0 | _Decimal32 | 4 |
 | file://:0:0:0:0 | _Decimal64 | 8 |
 | file://:0:0:0:0 | _Decimal128 | 16 |

cpp/ql/test/library-tests/unspecified_type/types/unspecified_type.expected

@@ -7,10 +7,13 @@
 | file://:0:0:0:0 | _Complex _Float64 | _Complex _Float64 |
 | file://:0:0:0:0 | _Complex _Float64x | _Complex _Float64x |
 | file://:0:0:0:0 | _Complex _Float128 | _Complex _Float128 |
+| file://:0:0:0:0 | _Complex __bf16 | _Complex __bf16 |
 | file://:0:0:0:0 | _Complex __float128 | _Complex __float128 |
+| file://:0:0:0:0 | _Complex __fp16 | _Complex __fp16 |
 | file://:0:0:0:0 | _Complex double | _Complex double |
 | file://:0:0:0:0 | _Complex float | _Complex float |
 | file://:0:0:0:0 | _Complex long double | _Complex long double |
+| file://:0:0:0:0 | _Complex std::float16_t | _Complex std::float16_t |
 | file://:0:0:0:0 | _Decimal32 | _Decimal32 |
 | file://:0:0:0:0 | _Decimal64 | _Decimal64 |
 | file://:0:0:0:0 | _Decimal128 | _Decimal128 |

cpp/ql/test/library-tests/variables/variables/types.expected

@@ -6,10 +6,13 @@
 | _Complex _Float64 | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex _Float64x | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex _Float128 | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
+| _Complex __bf16 | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex __float128 | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
+| _Complex __fp16 | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex double | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex float | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Complex long double | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
+| _Complex std::float16_t | BinaryFloatingPointType, ComplexNumberType |  |  |  |  |
 | _Decimal32 | Decimal32Type |  |  |  |  |
 | _Decimal64 | Decimal64Type |  |  |  |  |
 | _Decimal128 | Decimal128Type |  |  |  |  |