diff options
| author | Jason Merrill <jason@redhat.com> | 2020-05-11 14:05:46 -0400 |
|---|---|---|
| committer | Jason Merrill <jason@redhat.com> | 2020-05-11 14:50:41 -0400 |
| commit | f315d1477d5164cb8ec1a004ce368dd52d47092a (patch) | |
| tree | 2af6ff6fd5368ffc7e2955570f0e826bdf5a74b9 | |
| parent | 3a3e1ea9c674e50e402d5410970411ea6590f630 (diff) | |
c++: Tweak VLA representation.
If we put the SAVE_EXPR for a VLA size inside the MINUS_EXPR rather than
outside, it will work better with constant folding.
The equivalent change was made in the C front-end in 2004, in commit
r0-64535-g8b0b9aefd29dfe6398857bcf5628662e2f0e21f6
gcc/cp/ChangeLog
2020-05-11 Jason Merrill <jason@redhat.com>
* decl.c (compute_array_index_type_loc): Stabilize before building
the MINUS_EXPR.
| -rw-r--r-- | gcc/cp/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/cp/decl.c | 14 |
2 files changed, 14 insertions, 5 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index ab5e6abb866..9831c253668 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,10 @@ 2020-05-11 Jason Merrill <jason@redhat.com> + * decl.c (compute_array_index_type_loc): Stabilize before building + the MINUS_EXPR. + +2020-05-11 Jason Merrill <jason@redhat.com> + * decl.c (grokdeclarator): Adjust deprecated_state here. (start_decl): Not here. diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index adf94658420..dea1ba07c0e 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -10449,6 +10449,15 @@ compute_array_index_type_loc (location_t name_loc, tree name, tree size, itype = build_min (MINUS_EXPR, sizetype, size, integer_one_node); else { + if (!TREE_CONSTANT (size)) + { + /* A variable sized array. Arrange for the SAVE_EXPR on the inside + of the MINUS_EXPR, which allows the -1 to get folded with the +1 + that happens when building TYPE_SIZE. */ + size = variable_size (size); + stabilize_vla_size (size); + } + /* Compute the index of the largest element in the array. It is one less than the number of elements in the array. We save and restore PROCESSING_TEMPLATE_DECL so that computations in @@ -10466,11 +10475,6 @@ compute_array_index_type_loc (location_t name_loc, tree name, tree size, if (!TREE_CONSTANT (itype)) { - /* A variable sized array. */ - itype = variable_size (itype); - - stabilize_vla_size (itype); - if (sanitize_flags_p (SANITIZE_VLA) && current_function_decl != NULL_TREE) { |