[cfe-dev] Question about type checking of vector type operand on Sema

[JinGu Kang]

Hi all,

I have a question about type checking of vector type operand on Sema.

I tested a code and clang generated error as following:

source code:
typedef float float2  __attribute__((ext_vector_type(2)));

void test(float2 a, float2 b) {
   float2 t0 = (a + b) / 2;
}

error: can't convert between vector values of different size
       ('float __attribute__((ext_vector_type(2)))' and 'float')
   float2 t0 = (a + b) / 2;
                  ~~~~~~~ ^ ~

The problem is that "Sema::CheckVectorOperands()" function does not 
consider about the case of float vector and integer scalar. Does someone 
let me know why clang prevents this case? I couldn't find some 
information. I think clang need to support this case. Given this case, I 
send a simple patch to process this case.

Thanks,
JinGu Kang


-- 
JinGu Kang
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-------------- next part --------------
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 2a34822..9de45f5 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -6406,12 +6406,19 @@ QualType Sema::CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
         return LHSType;
       }
     }
-    if (EltTy->isRealFloatingType() && RHSType->isScalarType() &&
-        RHSType->isRealFloatingType()) {
-      int order = Context.getFloatingTypeOrder(EltTy, RHSType);
-      if (order > 0)
-        RHS = ImpCastExprToType(RHS.take(), EltTy, CK_FloatingCast);
-      if (order >= 0) {
+    if (EltTy->isRealFloatingType() && RHSType->isScalarType()) {
+      if (RHSType->isRealFloatingType()) {
+        int order = Context.getFloatingTypeOrder(EltTy, RHSType);
+        if (order > 0)
+          RHS = ImpCastExprToType(RHS.take(), EltTy, CK_FloatingCast);
+        if (order >= 0) {
+          RHS = ImpCastExprToType(RHS.take(), LHSType, CK_VectorSplat);
+          if (swapped) std::swap(RHS, LHS);
+          return LHSType;
+        }
+      }
+      if (RHSType->isIntegralType(Context)) {
+        RHS = ImpCastExprToType(RHS.take(), EltTy, CK_IntegralToFloating);
         RHS = ImpCastExprToType(RHS.take(), LHSType, CK_VectorSplat);
         if (swapped) std::swap(RHS, LHS);
         return LHSType;