From 1231f71f96a4e461f94394b4fb8cfa25587fbd96 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Wed, 26 Feb 2020 15:02:25 -0500 Subject: [PATCH] c++: Fix ICE with invalid array bounds [PR93789] r7-2111 introduced maybe_constant_value in cp_fully_fold. maybe_constant_value uses cxx_eval_outermost_constant_expr, which can clear TREE_CONSTANT: 6510 else if (non_constant_p && TREE_CONSTANT (r)) [...] 6529 TREE_CONSTANT (r) = false; In this test the array size is '(long int) "h"'. This used to be TREE_CONSTANT but given the change above, the flag will be cleared when we cp_fully_fold the array size in compute_array_index_type_loc. That means we don't emit an error in the 10391 else if (TREE_CONSTANT (size) block in the same function, and we go on. Then we compute ITYPE using cp_build_binary_op and use maybe_constant_value on it and suddenly we have something that's TREE_CONSTANT again. And then we crash in reshape_init_array_1 in tree_to_uhwi, because what we have doesn't fit in an unsigned HWI. icc accepts this code, but since we used to reject it, I see no desire to make this work, so don't use the folded result when we've lost the TREE_CONSTANT flag while evaluating the size. 2020-02-26 Marek Polacek PR c++/93789 - ICE with invalid array bounds. * decl.c (compute_array_index_type_loc): Don't use the folded size when folding cleared TREE_CONSTANT. * g++.dg/ext/vla22.C: New test. --- gcc/cp/ChangeLog | 6 ++++++ gcc/cp/decl.c | 11 ++++++++--- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/ext/vla22.C | 9 +++++++++ 4 files changed, 28 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/g++.dg/ext/vla22.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 051e415abee..b2d952d8220 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,9 @@ +2020-02-26 Marek Polacek + + PR c++/93789 - ICE with invalid array bounds. + * decl.c (compute_array_index_type_loc): Don't use the folded + size when folding cleared TREE_CONSTANT. + 2020-02-26 Iain Sandoe * class.c (classtype_has_non_deleted_copy_ctor): New. diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 1947c4ddb7f..e3f4b435a49 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -10338,9 +10338,14 @@ compute_array_index_type_loc (location_t name_loc, tree name, tree size, pedwarn (loc, OPT_Wpedantic, "size of array is not an integral constant-expression"); } - /* Use the folded result for VLAs, too; it will have resolved - SIZEOF_EXPR. */ - size = folded; + if (TREE_CONSTANT (size) && !TREE_CONSTANT (folded)) + /* We might have lost the TREE_CONSTANT flag e.g. when we are + folding a conversion from a pointer to integral type. In that + case issue an error below and don't treat this as a VLA. */; + else + /* Use the folded result for VLAs, too; it will have resolved + SIZEOF_EXPR. */ + size = folded; } /* Normally, the array-bound will be a constant. */ diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index d8a403e5139..085537d977b 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-02-26 Marek Polacek + + PR c++/93789 - ICE with invalid array bounds. + * g++.dg/ext/vla22.C: New test. + 2020-02-26 David Malcolm PR analyzer/93950 diff --git a/gcc/testsuite/g++.dg/ext/vla22.C b/gcc/testsuite/g++.dg/ext/vla22.C new file mode 100644 index 00000000000..2308ee748df --- /dev/null +++ b/gcc/testsuite/g++.dg/ext/vla22.C @@ -0,0 +1,9 @@ +// PR c++/93789 - ICE with invalid array bounds. +// { dg-do compile } +// { dg-options "" } + +void +f () +{ + const int tbl[(long) "h"] = { 12 }; // { dg-error "size of array .tbl. is not an integral constant-expression" } +} -- 2.30.2