4 files changed, 107 insertions, 0 deletions

diff --git a/source/slang/lower-to-ir.cpp b/source/slang/lower-to-ir.cpp
index 2242619d0..388ca884e 100644
--- a/source/slang/lower-to-ir.cpp
+++ b/source/slang/lower-to-ir.cpp
@@ -4107,10 +4107,56 @@ struct DeclLoweringVisitor : DeclVisitor<DeclLoweringVisitor, LoweredValInfo>
         IRGenContext* getContet() { return &subContextStorage; }
     };
 
+    LoweredValInfo lowerFunctionStaticConstVarDecl(
+        VarDeclBase* decl)
+    {
+        // We need to insert the constant at a level above
+        // the function being emitted. This will usually
+        // be the global scope, but it might be an outer
+        // generic if we are lowering a generic function.
+        //
+        NestedContext nestedContext(this);
+        auto subBuilder = nestedContext.getBuilder();
+        auto subContext = nestedContext.getContet();
+
+        subBuilder->setInsertInto(subBuilder->getFunc()->getParent());
+
+        IRType* subVarType = lowerType(subContext, decl->getType());
+
+        IRGlobalConstant* irConstant = subBuilder->createGlobalConstant(subVarType);
+        addVarDecorations(subContext, irConstant, decl);
+        addNameHint(context, irConstant, decl);
+        maybeSetRate(context, irConstant, decl);
+        subBuilder->addHighLevelDeclDecoration(irConstant, decl);
+
+        LoweredValInfo constantVal = LoweredValInfo::ptr(irConstant);
+        setValue(context, decl, constantVal);
+
+        if( auto initExpr = decl->initExpr )
+        {
+            NestedContext nestedInitContext(this);
+            auto initBuilder = nestedInitContext.getBuilder();
+            auto initContext = nestedInitContext.getContet();
+
+            initBuilder->setInsertInto(irConstant);
+
+            IRBlock* entryBlock = initBuilder->emitBlock();
+            initBuilder->setInsertInto(entryBlock);
+
+            LoweredValInfo initVal = lowerRValueExpr(initContext, initExpr);
+            initBuilder->emitReturn(getSimpleVal(initContext, initVal));
+        }
+
+        return constantVal;
+    }
 
     LoweredValInfo lowerFunctionStaticVarDecl(
         VarDeclBase*    decl)
     {
+        // We know the variable is `static`, but it might also be `const.
+        if(decl->HasModifier<ConstModifier>())
+            return lowerFunctionStaticConstVarDecl(decl);
+
         // A global variable may need to be generic, if one
         // of the outer declarations is generic.
         NestedContext nestedContext(this);
diff --git a/tests/cross-compile/function-static-const.slang b/tests/cross-compile/function-static-const.slang
new file mode 100644
index 000000000..7d933a04a
--- /dev/null
+++ b/tests/cross-compile/function-static-const.slang
@@ -0,0 +1,27 @@
+// function-static-const.slang
+
+//TEST:CROSS_COMPILE:-target dxbc-assembly  -entry main -stage fragment -profile sm_5_0
+
+// This test ensures that we compile `static const` variables inside
+// of functions to reasonable HLSL output so that we don't introduce
+// unexpected overhead by treating them as just `static`.
+//
+
+int test(int val)
+{
+	static const int kArray[] = {
+		1, 2, 3, 4, 5, 6, 7, 8,
+		9, 10, 11, 12, 13, 14, 15, 16
+	};
+	return kArray[val];
+}
+
+cbuffer C
+{
+    int index;
+}
+
+float4 main() : SV_Target
+{
+	return test(index);
+}
diff --git a/tests/cross-compile/function-static-const.slang.hlsl b/tests/cross-compile/function-static-const.slang.hlsl
new file mode 100644
index 000000000..a4f1118eb
--- /dev/null
+++ b/tests/cross-compile/function-static-const.slang.hlsl
@@ -0,0 +1,27 @@
+// function-static-const.slang
+//TEST_IGNORE_FILE
+
+#pragma pack_matrix(column_major)
+
+struct SLANG_ParameterGroup_C_0
+{
+    int index_0;
+};
+
+cbuffer C_0 : register(b0)
+{
+    SLANG_ParameterGroup_C_0 C_0;
+}
+
+static const int  kArray_0[16] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
+
+int test_0(int val_0)
+{
+    return kArray_0[val_0];
+}
+
+vector<float,4> main() : SV_TARGET
+{
+    int _S1 = test_0(C_0.index_0);
+    return (vector<float,4>) _S1;
+}
diff --git a/tools/slang-test/slang-test-main.cpp b/tools/slang-test/slang-test-main.cpp
index c0e5bd95b..1f6b4cdb0 100644
--- a/tools/slang-test/slang-test-main.cpp
+++ b/tools/slang-test/slang-test-main.cpp
@@ -697,6 +697,13 @@ TestResult runCrossCompilerTest(TestContext* context, TestInput& input)
                 expectedSpawner.pushArgument("dxc");
                 break;
             }
+            case SLANG_DXBC_ASM:
+            {
+                expectedSpawner.pushArgument(filePath + ".hlsl");
+                expectedSpawner.pushArgument("-pass-through");
+                expectedSpawner.pushArgument("fxc");
+                break;
+            }
             default:
             {
                 expectedSpawner.pushArgument(filePath + ".glsl");