[TVMScript] Fix parse minimal i32 literal for tir script (apache#12772)

This change tries to fix an issue due to apache#12515.

Previously the logic for `-2147483648` is  `parse(-literal)` = `-parse(literal)`, and all integer literals are converted to i32 (either the literal value actually overflow or not).

Since after apache#12515, parse `2147483648` results in an i64 typed integer rather than i32, `-2147483648` then becomes an i64 integer too, which is not reasonable.

python/tvm/script/parser.py

@@ -906,6 +906,13 @@ def transform_Call(self, node):
                 )
             if node.func_name.name in self._unaryop_maker:
                 rhs = self.transform(node.params[0])
+                if node.func_name.name == ast.BuiltinOp.USub and isinstance(
+                    node.params[0], ast.Constant
+                ):
+                    # '-literal' should be parsed together for proper literal type inference
+                    if not isinstance(rhs, (tvm.tir.IntImm, tvm.tir.FloatImm)):
+                        self.report_error("The literal is illegal after -", node.params[0].span)
+                    return tvm.tir.const(-rhs.value)
                 return self._unaryop_maker[node.func_name.name](
                     rhs, span=tvm_span_from_synr(node.span)
                 )

tests/python/unittest/test_tvmscript_roundtrip.py

@@ -3381,6 +3381,15 @@ def func(
     return func
 
 
+def minimal_i32_literal():
+    @T.prim_func
+    def func() -> None:
+        T.evaluate(T.int32(-2147483648))
+        T.evaluate(-T.int64(2147483648))
+
+    return func
+
+
 ir_generator = tvm.testing.parameter(
     opt_gemm_normalize,
     opt_gemm_lower,
@@ -3423,6 +3432,7 @@ def func(
     decl_buffer,
     allocate_and_decl_buffer,
     float_infinity,
+    minimal_i32_literal,
 )