On Wed, Feb 07, 2018 at 04:21:43PM -0500, Jason Merrill wrote: > On Wed, Feb 7, 2018 at 4:14 PM, Jakub Jelinek <[email protected]> wrote: > > On Wed, Feb 07, 2018 at 03:52:39PM -0500, Jason Merrill wrote: > >> > E.g. the constexpr function uses > >> > same_type_ignoring_top_level_qualifiers_p > >> > instead of == type comparisons, the COMPONENT_REF stuff, ... > >> > >> > For poly_* stuff, I think Richard S. wants to introduce it into the FEs > >> > at > >> > some point, but I could be wrong; certainly it hasn't been done yet and > >> > generally, poly*int seems to be a nightmare to deal with. > >> > >> Yes, I understand how we got to this point, but having the functions > >> diverge because of this guideline seems like a mistake. And there > >> seem to be two ways to avoid the divergence: make an exception to the > >> guideline, or move the function. > > > > Functionally, I think the following patch should turn fold_indirect_ref_1 > > to be equivalent to the patched constexpr.c version (with the known > > documented differences), so if this is the obstackle for the acceptance > > of the patch, I can test this. > > > > Otherwise, I must say I have no idea how to share the code, > > same_type_ignoring_qualifiers is only a C++ FE function, so the middle-end > > can't use it even conditionally, and similarly with the TBAA issues. > > Again, can we make an exception and use poly_int in this function > because it's mirroring a middle-end function?
So like this if it passes bootstrap/regtest? It is kind of bidirectional merge of changes between the 2 functions, except for intentional differences (e.g. the same_type_ignoring_top_level_qualifiers_p vs. ==, in_gimple_form stuff in fold-const.c, the C++ specific empty class etc. handling in constexpr.c etc.). 2018-01-26 Marek Polacek <[email protected]> Jakub Jelinek <[email protected]> PR c++/83659 * fold-const.c (fold_indirect_ref_1): Use VECTOR_TYPE_P macro. Formatting fixes. Verify first that tree_fits_poly_int64_p (op01). Sync some changes from cxx_fold_indirect_ref. * constexpr.c (cxx_fold_indirect_ref): Sync some changes from fold_indirect_ref_1, including poly_*int64. Verify first that tree_fits_poly_int64_p (op01). Formatting fixes. * g++.dg/torture/pr83659.C: New test. --- gcc/fold-const.c.jj 2018-01-26 12:43:23.140922419 +0100 +++ gcc/fold-const.c 2018-02-08 12:43:50.654727317 +0100 @@ -14115,6 +14115,7 @@ fold_indirect_ref_1 (location_t loc, tre { tree op = TREE_OPERAND (sub, 0); tree optype = TREE_TYPE (op); + /* *&CONST_DECL -> to the value of the const decl. */ if (TREE_CODE (op) == CONST_DECL) return DECL_INITIAL (op); @@ -14148,12 +14149,13 @@ fold_indirect_ref_1 (location_t loc, tre && type == TREE_TYPE (optype)) return fold_build1_loc (loc, REALPART_EXPR, type, op); /* *(foo *)&vectorfoo => BIT_FIELD_REF<vectorfoo,...> */ - else if (TREE_CODE (optype) == VECTOR_TYPE + else if (VECTOR_TYPE_P (optype) && type == TREE_TYPE (optype)) { tree part_width = TYPE_SIZE (type); tree index = bitsize_int (0); - return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); + return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, + index); } } @@ -14171,8 +14173,17 @@ fold_indirect_ref_1 (location_t loc, tre op00type = TREE_TYPE (op00); /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ - if (TREE_CODE (op00type) == VECTOR_TYPE - && type == TREE_TYPE (op00type)) + if (VECTOR_TYPE_P (op00type) + && type == TREE_TYPE (op00type) + /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, + but we want to treat offsets with MSB set as negative. + For the code below negative offsets are invalid and + TYPE_SIZE of the element is something unsigned, so + check whether op01 fits into poly_int64, which implies + it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and + then just use poly_uint64 because we want to treat the + value as unsigned. */ + && tree_fits_poly_int64_p (op01)) { tree part_width = TYPE_SIZE (type); poly_uint64 max_offset @@ -14199,16 +14210,16 @@ fold_indirect_ref_1 (location_t loc, tre && type == TREE_TYPE (op00type)) { tree type_domain = TYPE_DOMAIN (op00type); - tree min = size_zero_node; + tree min_val = size_zero_node; if (type_domain && TYPE_MIN_VALUE (type_domain)) - min = TYPE_MIN_VALUE (type_domain); + min_val = TYPE_MIN_VALUE (type_domain); offset_int off = wi::to_offset (op01); offset_int el_sz = wi::to_offset (TYPE_SIZE_UNIT (type)); offset_int remainder; off = wi::divmod_trunc (off, el_sz, SIGNED, &remainder); - if (remainder == 0 && TREE_CODE (min) == INTEGER_CST) + if (remainder == 0 && TREE_CODE (min_val) == INTEGER_CST) { - off = off + wi::to_offset (min); + off = off + wi::to_offset (min_val); op01 = wide_int_to_tree (sizetype, off); return build4_loc (loc, ARRAY_REF, type, op00, op01, NULL_TREE, NULL_TREE); --- gcc/cp/constexpr.c.jj 2018-02-06 13:12:48.072808498 +0100 +++ gcc/cp/constexpr.c 2018-02-08 12:43:59.526722279 +0100 @@ -3025,9 +3025,10 @@ cxx_eval_vec_init (const constexpr_ctx * static tree cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) { - tree sub, subtype; + tree sub = op0; + tree subtype; + poly_uint64 const_op01; - sub = op0; STRIP_NOPS (sub); subtype = TREE_TYPE (sub); if (!POINTER_TYPE_P (subtype)) @@ -3082,7 +3083,8 @@ cxx_fold_indirect_ref (location_t loc, t { tree part_width = TYPE_SIZE (type); tree index = bitsize_int (0); - return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, index); + return fold_build3_loc (loc, BIT_FIELD_REF, type, op, part_width, + index); } /* Also handle conversion to an empty base class, which is represented with a NOP_EXPR. */ @@ -3107,7 +3109,7 @@ cxx_fold_indirect_ref (location_t loc, t } } else if (TREE_CODE (sub) == POINTER_PLUS_EXPR - && TREE_CODE (TREE_OPERAND (sub, 1)) == INTEGER_CST) + && poly_int_tree_p (TREE_OPERAND (sub, 1), &const_op01)) { tree op00 = TREE_OPERAND (sub, 0); tree op01 = TREE_OPERAND (sub, 1); @@ -3121,29 +3123,37 @@ cxx_fold_indirect_ref (location_t loc, t /* ((foo*)&vectorfoo)[1] => BIT_FIELD_REF<vectorfoo,...> */ if (VECTOR_TYPE_P (op00type) - && (same_type_ignoring_top_level_qualifiers_p - (type, TREE_TYPE (op00type)))) + && same_type_ignoring_top_level_qualifiers_p + (type, TREE_TYPE (op00type)) + /* POINTER_PLUS_EXPR second operand is sizetype, unsigned, + but we want to treat offsets with MSB set as negative. + For the code below negative offsets are invalid and + TYPE_SIZE of the element is something unsigned, so + check whether op01 fits into poly_int64, which implies + it is from 0 to INTTYPE_MAXIMUM (HOST_WIDE_INT), and + then just use poly_uint64 because we want to treat the + value as unsigned. */ + && tree_fits_poly_int64_p (op01)) { - HOST_WIDE_INT offset = tree_to_shwi (op01); tree part_width = TYPE_SIZE (type); - unsigned HOST_WIDE_INT part_widthi = tree_to_shwi (part_width)/BITS_PER_UNIT; - unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT; - tree index = bitsize_int (indexi); - - if (known_lt (offset / part_widthi, - TYPE_VECTOR_SUBPARTS (op00type))) - return fold_build3_loc (loc, - BIT_FIELD_REF, type, op00, - part_width, index); - + poly_uint64 max_offset + = (tree_to_uhwi (part_width) / BITS_PER_UNIT + * TYPE_VECTOR_SUBPARTS (op00type)); + if (known_lt (const_op01, max_offset)) + { + tree index = bitsize_int (const_op01 * BITS_PER_UNIT); + return fold_build3_loc (loc, + BIT_FIELD_REF, type, op00, + part_width, index); + } } /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ else if (TREE_CODE (op00type) == COMPLEX_TYPE && (same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op00type)))) { - tree size = TYPE_SIZE_UNIT (type); - if (tree_int_cst_equal (size, op01)) + if (known_eq (wi::to_poly_offset (TYPE_SIZE_UNIT (type)), + const_op01)) return fold_build1_loc (loc, IMAGPART_EXPR, type, op00); } /* ((foo *)&fooarray)[1] => fooarray[1] */ @@ -3198,7 +3208,8 @@ cxx_fold_indirect_ref (location_t loc, t { tree type_domain; tree min_val = size_zero_node; - tree newsub = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); + tree newsub + = cxx_fold_indirect_ref (loc, TREE_TYPE (subtype), sub, NULL); if (newsub) sub = newsub; else --- gcc/testsuite/g++.dg/torture/pr83659.C.jj 2018-02-08 12:29:11.994353867 +0100 +++ gcc/testsuite/g++.dg/torture/pr83659.C 2018-02-08 12:29:11.994353867 +0100 @@ -0,0 +1,18 @@ +// PR c++/83659 +// { dg-do compile } + +typedef int V __attribute__ ((__vector_size__ (16))); +V a; +V b[2]; + +int +foo () +{ + return reinterpret_cast <int *> (&a)[-1] += 1; +} + +int +bar () +{ + return reinterpret_cast <int *> (&a[1])[-1]; +} Jakub
