Hi! On Fri, 15 Jul 2016 15:19:59 +0200 (CEST), Richard Biener <rguent...@suse.de> wrote: > This PR shows that
(There is also PR71901 suspected to be related; David CCed.)
> array_ref_element_size may apply spurious casts which
> in turn end up confusing VN/PRE.
>
> Fixed as follows, bootstrapped on x86_64-unknown-linux-gnu, testing in
> progress.
Thanks, this resolves PR71893 for nvptx:
> PR tree-optimization/71893
> * tree-ssa-pre.c (create_component_ref_by_pieces_1): Compensate
> for sizetype cast added by array_ref_element_size.
> * tree-ssa-sccvn.c (copy_reference_ops_from_ref): Likewise.
>
> Index: gcc/tree-ssa-pre.c
> ===================================================================
> *** gcc/tree-ssa-pre.c (revision 238370)
> --- gcc/tree-ssa-pre.c (working copy)
> *************** create_component_ref_by_pieces_1 (basic_
> *** 2576,2581 ****
> --- 2587,2595 ----
> {
> genop3 = size_binop (EXACT_DIV_EXPR, genop3,
> size_int (TYPE_ALIGN_UNIT (elmt_type)));
> + /* We may have a useless conversion added by
> + array_ref_element_size via copy_reference_opts_from_ref. */
> + STRIP_USELESS_TYPE_CONVERSION (genop3);
> genop3 = find_or_generate_expression (block, genop3, stmts);
> if (!genop3)
> return NULL_TREE;
> Index: gcc/tree-ssa-sccvn.c
> ===================================================================
> *** gcc/tree-ssa-sccvn.c (revision 238370)
> --- gcc/tree-ssa-sccvn.c (working copy)
> *************** copy_reference_ops_from_ref (tree ref, v
> *** 810,815 ****
> --- 810,818 ----
> /* Always record lower bounds and element size. */
> temp.op1 = array_ref_low_bound (ref);
> temp.op2 = array_ref_element_size (ref);
> + /* array_ref_element_size forces the result to sizetype
> + even if that is the same as bitsizetype. */
> + STRIP_USELESS_TYPE_CONVERSION (temp.op2);
> if (TREE_CODE (temp.op0) == INTEGER_CST
> && TREE_CODE (temp.op1) == INTEGER_CST
> && TREE_CODE (temp.op2) == INTEGER_CST)
Grüße
Thomas
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