On Wed, Jun 28, 2017 at 2:36 PM, Richard Sandiford
<richard.sandif...@linaro.org> wrote:
> Index: gcc/tree-data-ref.c
> ===================================================================
> --- gcc/tree-data-ref.c 2017-06-28 14:33:41.294720044 +0100
> +++ gcc/tree-data-ref.c 2017-06-28 14:35:30.475155670 +0100
> @@ -749,15 +749,29 @@ canonicalize_base_object_address (tree a
> return build_fold_addr_expr (TREE_OPERAND (addr, 0));
> }
>
> -/* Analyzes the behavior of the memory reference DR in the innermost loop or
> - basic block that contains it. Returns true if analysis succeed or false
> - otherwise. */
> +/* Analyze the behavior of memory reference DR. There are two modes:
> +
> + - BB analysis. In this case we simply split the address into base,
> + init and offset components, without reference to any containing loop.
> + The resulting base and offset are general expressions and they can
> + vary arbitrarily from one iteration of the containing loop to the next.
> + The step is always zero.
> +
> + - loop analysis. In this case we analyze the reference both wrt LOOP
> + and on the basis that the reference occurs (is "used") in LOOP;
> + see the comment above analyze_scalar_evolution_in_loop for more
> + information about this distinction. The base, init, offset and
> + step fields are all invariant in LOOP.
> +
> + Perform BB analysis if LOOP is null, or if LOOP is the function's
> + dummy outermost loop. In other cases perform loop analysis.
> +
> + Return true if the analysis succeeded and store the results in DR if so.
> + BB analysis can only fail for bitfield or reversed-storage accesses. */
>
> bool
> -dr_analyze_innermost (struct data_reference *dr, struct loop *nest)
> +dr_analyze_innermost (struct data_reference *dr, struct loop *loop)
> {
> - gimple *stmt = DR_STMT (dr);
> - struct loop *loop = loop_containing_stmt (stmt);
> tree ref = DR_REF (dr);
> HOST_WIDE_INT pbitsize, pbitpos;
> tree base, poffset;
> @@ -806,22 +820,11 @@ dr_analyze_innermost (struct data_refere
>
> if (in_loop)
A nit. No need to use bool variable now? We can check loop != NULL instead.
Thanks,
bin
