From b07c365100c92687361aa062ecf89c49650b8930 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Mon, 29 Jan 2018 20:54:12 +0000 Subject: [PATCH] re PR c++/83996 (ICE with zero-sized array) PR c++/83996 * constexpr.c (cxx_fold_indirect_ref): Compute ((foo *)&fooarray)[1] => fooarray[1] in offset_int. * g++.dg/ext/pr83996.C: New test. From-SVN: r257160 --- gcc/cp/ChangeLog | 6 ++++++ gcc/cp/constexpr.c | 16 +++++++++++----- gcc/testsuite/ChangeLog | 3 +++ gcc/testsuite/g++.dg/ext/pr83996.C | 11 +++++++++++ 4 files changed, 31 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/g++.dg/ext/pr83996.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 90e8ff18203..e8b0e1e140a 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2018-01-29 Marek Polacek + + PR c++/83996 + * constexpr.c (cxx_fold_indirect_ref): Compute ((foo *)&fooarray)[1] + => fooarray[1] in offset_int. + 2018-01-29 Jason Merrill PR c++/83942 - wrong unused warning with static_cast. diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 4d2ee4a28fc..0a1944f6dad 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3143,11 +3143,17 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base) tree min_val = size_zero_node; if (type_domain && TYPE_MIN_VALUE (type_domain)) min_val = TYPE_MIN_VALUE (type_domain); - op01 = size_binop_loc (loc, EXACT_DIV_EXPR, op01, - TYPE_SIZE_UNIT (type)); - op01 = size_binop_loc (loc, PLUS_EXPR, op01, min_val); - return build4_loc (loc, ARRAY_REF, type, op00, op01, - NULL_TREE, NULL_TREE); + 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_val) == INTEGER_CST) + { + 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); + } } /* Also handle conversion to an empty base class, which is represented with a NOP_EXPR. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 3713a81227c..a74854b3e12 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -3,6 +3,9 @@ PR c/83966 * gcc.dg/format/Wsuggest-attribute-1.c: New test. + PR c++/83996 + * g++.dg/ext/pr83996.C: New test. + 2018-01-29 Richard Biener PR tree-optimization/84057 diff --git a/gcc/testsuite/g++.dg/ext/pr83996.C b/gcc/testsuite/g++.dg/ext/pr83996.C new file mode 100644 index 00000000000..e663d728349 --- /dev/null +++ b/gcc/testsuite/g++.dg/ext/pr83996.C @@ -0,0 +1,11 @@ +// PR c++/83996 +// { dg-do compile } +// { dg-options "" } + +int z[] = { }; + +int +main (void) +{ + __builtin_printf ("%d\n", *(z + 1)); +} -- 2.30.2