Constant-fold for the type-casting in switch-case labels

source/slang/slang-check-expr.cpp

@@ -2068,7 +2068,19 @@ IntVal* SemanticsVisitor::tryConstantFoldExpr(
             return nullptr;
         if (!isValidCompileTimeConstantType(substType))
             return nullptr;
-        auto val = tryConstantFoldExpr(typeCastOperand, kind, circularityInfo);
+
+        IntVal* val = tryConstantFoldExpr(typeCastOperand, kind, circularityInfo);
+        if (!val)
+        {
+            if (auto floatLitExpr = typeCastOperand.as<FloatingPointLiteralExpr>())
+            {
+                // When explicitly casting from float type to integer type, let's fold it as
+                // an integer value.
+                const IntegerLiteralValue value = IntegerLiteralValue(floatLitExpr.getExpr()->value);
+                val = m_astBuilder->getIntVal(substType, value);
+            }
+        }
+
         if (val)
         {
             if (!expr.getExpr()->type)

tests/bugs/gh-5372.slang

@@ -0,0 +1,45 @@
+//TEST:SIMPLE(filecheck=SPV): -allow-glsl -target spirv-asm -entry vertexMain -stage vertex
+
+// This test is to make sure the constant-folding works for the switch-case label.
+// The shader code is from VK-CTS but modified,
+//   dEQP-VK.glsl.switch.const_expr_in_label_dynamic_fragment
+
+layout(location = 0) in highp vec4 a_position;
+layout(location = 1) in highp vec4 a_coords;
+
+layout(location = 0) out mediump vec4 v_color;
+layout (std140, set=0, binding=0) uniform buffer0 { highp int ui_two; };
+
+void vertexMain(void)
+{
+    gl_Position = a_position;
+    highp vec4 coords = a_coords;
+    mediump vec3 res = vec3(0.0);
+
+    const int t = 2;
+    switch (ui_two)
+    {
+        //SPV-NOT:([[# @LINE+1]]): error
+        case int(0.0):
+            res = coords.xyz;
+            break;
+
+        //SPV-NOT:([[# @LINE+1]]): error
+        case 2-1:
+            res = coords.wzy;
+            break;
+
+        //SPV-NOT:([[# @LINE+1]]): error
+        case 3&(1<<1):
+            res = coords.yzw;
+            break;
+
+        //SPV-NOT:([[# @LINE+1]]): error
+        case t+1:
+            res = coords.zyx;
+            break;
+    }
+
+    v_color = vec4(res, 1.0);
+}
+

tests/diagnostics/attribute-error.slang

@@ -2,7 +2,7 @@
 
 // Tests reflection of user defined attributes.
 
-//DIAGNOSTIC_TEST:REFLECTION:-stage compute -entry main -target hlsl
+//TEST:SIMPLE(filecheck=REFLECTION):-stage compute -entry main -target hlsl
 
 [__AttributeUsage(_AttributeTargets.Struct)]
 struct MyStructAttribute
@@ -16,9 +16,11 @@ struct DefaultValueAttribute
     int iParam;
 };
 
+//REFLECTION:([[# @LINE+1]]): error 30019: expected an expression of type 'float', got 'String'
 [MyStruct(0, "stringVal")] // attribute arg type mismatch
 struct A
 {
+    //REFLECTION:([[# @LINE+1]]): error 31002: attribute 'MyStruct' is not valid here
     [MyStruct(0, 10.0)] // attribute does not apply to this construct
     float x;
     [DefaultValue(2.0)] // attribute arg type mismatch
@@ -31,4 +33,4 @@ ParameterBlock<A> param;
 void main(
     uint3 dispatchThreadID : SV_DispatchThreadID)
 {
-}
+}