disallow splatting things with bitvectors, add tests to show casting bitvectors not allowed. At test showing splatting union is not allowed. At test showing splatting union in elementwise cast is not allowed.

Author: spall

clang/lib/Sema/SemaHLSL.cpp

@@ -2771,7 +2771,7 @@ bool SemaHLSL::CanPerformScalarCast(QualType SrcTy, QualType DestTy) {
 }
 
 // Detect if a type contains a bitfield. Will be removed when
-// bitfield support is added to HLSLElementwiseCast
+// bitfield support is added to HLSLElementwiseCast and HLSLSplatCast
 bool SemaHLSL::ContainsBitField(QualType BaseTy) {
   llvm::SmallVector<QualType, 16> WorkList;
   WorkList.push_back(BaseTy);
@@ -2822,11 +2822,16 @@ bool SemaHLSL::CanPerformSplatCast(Expr *Src, QualType DestTy) {
   if (SrcVecTy)
     SrcTy = SrcVecTy->getElementType();
 
+  if (ContainsBitField(DestTy))
+    return false;
+
   llvm::SmallVector<QualType> DestTypes;
   BuildFlattenedTypeList(DestTy, DestTypes);
 
-  for (unsigned i = 0; i < DestTypes.size(); i++) {
-    if (!CanPerformScalarCast(SrcTy, DestTypes[i]))
+  for (unsigned I = 0, Size = DestTypes.size(); I < Size; I++) {
+    if (DestTypes[I]->isUnionType())
+      return false;
+    if (!CanPerformScalarCast(SrcTy, DestTypes[I]))
       return false;
   }
   return true;

clang/test/SemaHLSL/Language/ElementwiseCast-errors.hlsl

@@ -27,3 +27,23 @@ export void cantCast3() {
   S s = (S)C;
   // expected-error@-1 {{no matching conversion for C-style cast from 'int2' (aka 'vector<int, 2>') to 'S'}}
 }
+
+struct R {
+// expected-note@-1 {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int2' (aka 'vector<int, 2>') to 'const R' for 1st argument}}
+// expected-note@-2 {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int2' (aka 'vector<int, 2>') to 'R' for 1st argument}}
+// expected-note@-3 {{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
+  int A;
+  union {
+    float F;
+    int4 G;
+  };
+};
+
+export void cantCast4() {
+  int2 A = {1,2};
+  R r = R(A);
+  // expected-error@-1 {{no matching conversion for functional-style cast from 'int2' (aka 'vector<int, 2>') to 'R'}}
+  R r2 = {1, 2};
+  int2 B = (int2)r2;
+  // expected-error@-1 {{cannot convert 'R' to 'int2' (aka 'vector<int, 2>') without a conversion operator}}
+}

clang/test/SemaHLSL/Language/SplatCasts-errors.hlsl

@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -verify
+
+struct S {
+// expected-note@-1 {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const S' for 1st argument}}
+// expected-note@-2 {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'S' for 1st argument}}
+// expected-note@-3 {{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
+  int A : 8;
+  int B;
+};
+
+struct R {
+// expected-note@-1 {{candidate constructor (the implicit copy constructor) not viable: no known conversion from 'int' to 'const R' for 1st argument}}
+// expected-note@-2 {{candidate constructor (the implicit move constructor) not viable: no known conversion from 'int' to 'R' for 1st argument}}
+// expected-note@-3 {{candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 1 was provided}}
+  int A;
+  union {
+    float F;
+    int4 G;
+  };
+};
+
+// casting types which contain bitfields is not yet supported.
+export void cantCast() {
+  S s = (S)1;
+  // expected-error@-1 {{no matching conversion for C-style cast from 'int' to 'S'}}
+}
+
+// Can't cast a union
+export void cantCast2() {
+  R r = (R)1;
+  // expected-error@-1 {{no matching conversion for C-style cast from 'int' to 'R'}}
+}