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| author | Martin Uecker <uecker@gcc.gnu.org> | 2021-11-17 14:20:59 +0100 |
|---|---|---|
| committer | Martin Uecker <muecker@gwdg.de> | 2021-11-17 14:29:50 +0100 |
| commit | 4e6bf0b9dd5585df1a1472d6a93b9fff72fe2524 (patch) | |
| tree | dfc6be0b46a1b565c69dd1ddfd094b834465e9f1 /gcc/c-family/c-common.c | |
| parent | 077425c890927eefacb765ab5236060de9859e82 (diff) | |
| download | gcc-4e6bf0b9dd5585df1a1472d6a93b9fff72fe2524.tar.gz | |
Fix ICE when mixing VLAs and statement expressions [PR91038]
When returning VM-types from statement expressions, this can
lead to an ICE when declarations from the statement expression
are referred to later. Most of these issues can be addressed by
gimplifying the base expression earlier in gimplify_compound_lval.
Another issue is fixed by wrapping the pointer expression in
pointer_int_sum. This fixes PR91038 and some of the test cases
from PR29970 (structs with VLA members need further work).
gcc/
PR c/91038
PR c/29970
* gimplify.c (gimplify_var_or_parm_decl): Update comment.
(gimplify_compound_lval): Gimplify base expression first.
(gimplify_target_expr): Add comment.
gcc/c-family/
PR c/91038
PR c/29970
* c-common.c (pointer_int_sum): Make sure pointer expressions
are evaluated first when the size expression depends on for
variably-modified types.
gcc/testsuite/
PR c/91038
PR c/29970
* gcc.dg/vla-stexp-3.c: New test.
* gcc.dg/vla-stexp-4.c: New test.
* gcc.dg/vla-stexp-5.c: New test.
* gcc.dg/vla-stexp-6.c: New test.
* gcc.dg/vla-stexp-7.c: New test.
* gcc.dg/vla-stexp-8.c: New test.
* gcc.dg/vla-stexp-9.c: New test.
Diffstat (limited to 'gcc/c-family/c-common.c')
| -rw-r--r-- | gcc/c-family/c-common.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 90e8ec87b6b..ca7d69c4f76 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -3306,7 +3306,19 @@ pointer_int_sum (location_t loc, enum tree_code resultcode, TREE_TYPE (result_type))) size_exp = integer_one_node; else - size_exp = size_in_bytes_loc (loc, TREE_TYPE (result_type)); + { + size_exp = size_in_bytes_loc (loc, TREE_TYPE (result_type)); + /* Wrap the pointer expression in a SAVE_EXPR to make sure it + is evaluated first when the size expression may depend + on it for VM types. */ + if (TREE_SIDE_EFFECTS (size_exp) + && TREE_SIDE_EFFECTS (ptrop) + && variably_modified_type_p (TREE_TYPE (ptrop), NULL)) + { + ptrop = save_expr (ptrop); + size_exp = build2 (COMPOUND_EXPR, TREE_TYPE (intop), ptrop, size_exp); + } + } /* We are manipulating pointer values, so we don't need to warn about relying on undefined signed overflow. We disable the |