Parametrized dtype overridden in test_autotuner; wrong variable in test_integration error message

Start with test/kernel/test_autotuner.py and inspect the three TestQuantFlow methods and their dtype assertions. Run pytest test/kernel/test_autotuner.py -v to confirm both dtype variants exercise their parametrized values. Then inspect test_integration.py around lines 641-642 and ensure the failure message reports the SQNR for the tested output; done means the parametrized tests cover both dtypes and the message uses the checked value.

Bug 1: Parametrized dtype silently overridden in test_autotuner.py

All three test methods in TestQuantFlow are parametrized over dtype (both torch.bfloat16 and torch.float16), but each one immediately overwrites it with a hardcoded dtype = torch.bfloat16:

This means the float16 test cases never actually test float16. They silently run with bfloat16 instead, giving false test coverage.

Additionally, test_int_scaled_mm asserts out32_1.dtype == torch.bfloat16 on line 96, which is hardcoded instead of using the parametrized dtype. If the override were removed without fixing this assertion, float16 tests would fail.

Bug 2: Wrong variable in error message in test_integration.py

Line 641-642:

assert SQNR(ref_f, test) > min_sqnr, (
    f"got sqnr: {SQNR(ref_f, ref_q)}, expected: {min_sqnr}"
)

The assertion checks SQNR(ref_f, test), but the error message prints SQNR(ref_f, ref_q). ref_q is the compiled quantized reference computed earlier, not the value being tested. When this assertion fails, the error message shows the wrong SQNR value — the one between the float reference and the compiled quantized reference, not between the float reference and the actual test output.

Should be:

f"got sqnr: {SQNR(ref_f, test)}, expected: {min_sqnr}"

Reproduction

Bug 1: Run pytest test/kernel/test_autotuner.py -v and observe that test_int_mm_cuda_float16 and similar cases produce identical results to the bfloat16 variants.

Bug 2: No runtime failure — the bug only manifests in error messages when the assertion fails.