[TOSA] Make validation pass isValidElementType check more strict (#119671)

The validation pass is used to check alignment of the IR against the
TOSA specification. This commit updates the `isValidElement` check to
more strictly align with the specifications supported element types.

Signed-off-by: Luke Hutton <[email protected]>

Author: lhutton1

mlir/lib/Dialect/Tosa/Transforms/TosaValidation.cpp

@@ -524,18 +524,8 @@ bool TosaValidation::isValidElementType(Type type) {
     if (!isEnabledProfile(TosaProfileEnum::MainInference))
       return false;
     return type.isF32() || type.isF16() || type.isBF16();
-  }
-  if (auto intTy = dyn_cast<IntegerType>(type)) {
-    if (intTy.isUnsigned()) {
-      switch (intTy.getWidth()) {
-      case 8:
-      case 16:
-        return true;
-      default:
-        return false;
-      }
-    } else {
-      // Signless - treated as signed.
+  } else if (auto intTy = dyn_cast<IntegerType>(type)) {
+    if (intTy.isSignless()) {
       switch (intTy.getWidth()) {
       case 1:
       case 4:
@@ -544,13 +534,10 @@ bool TosaValidation::isValidElementType(Type type) {
       case 32:
       case 48:
         return true;
-      default:
-        return false;
       }
     }
-    return false;
   }
-  return true;
+  return false;
 }
 
 void TosaValidation::runOnOperation() {

mlir/test/Dialect/Tosa/level_check.mlir

@@ -143,6 +143,14 @@ func.func @test_const_f64(%arg0 : tensor<1xf64>) {
 
 // -----
 
+func.func @test_const_ui8(%arg0 : tensor<1xui8>) {
+  // expected-error@+1 {{'tosa.const' op is not profile-aligned: element type 'ui8' is not legal}}
+  %0 = "tosa.const"() {value = dense<0> : tensor<1xui8>} : () -> tensor<1xui8>
+  return
+}
+
+// -----
+
 func.func @test_avgpool2d_kernel_y(%arg0: tensor<1x32x32x8xf32>) -> tensor<1x32x32x8xf32> {
   // expected-error@+1 {{'tosa.avg_pool2d' op failed level check: kernel <= MAX_KERNEL}}
   %0 = "tosa.avg_pool2d"(%arg0) {kernel = array<i64: 8193, 1>, pad = array<i64: 4, 4, 4, 4>, stride = array<i64: 1, 1>, acc_type = f32} :