[FRONTEND][BACKEND] Fixed various bugs (#819)

- Fixed bugs on layout conversions for int1 data (we should use int8
internally for int1 data to prevent llvm from using vec<i1> which has
different semantics)
- Fixed semantics of some casts to bool in the frontend

python/triton/compiler.py

@@ -993,6 +993,7 @@ def _compile(fn, signature: str, device: int = -1, constants=dict(), specializat
     module = optimize_tritongpu_ir(module, num_stages)
     if output == "ttgir":
         return module.str()
+
     if extern_libs:
         add_external_libs(module, extern_libs)