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| author | Richard Biener <rguenther@suse.de> | 2025-01-28 16:20:30 +0100 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2025-01-28 16:50:07 +0100 |
| commit | 54bdeca3c6214485d15454df30183a56ad3e473b (patch) | |
| tree | d8c284208420e802cb43f58779f096f4a27d1fd5 /gcc | |
| parent | 50c37516958319e10a137d2b3dba7b070523248a (diff) | |
| download | gcc-54bdeca3c6214485d15454df30183a56ad3e473b.zip gcc-54bdeca3c6214485d15454df30183a56ad3e473b.tar.gz gcc-54bdeca3c6214485d15454df30183a56ad3e473b.tar.bz2 | |
middle-end/118684 - wrongly aligned stack local during expansion
The following fixes a not properly aligned stack temporary created
during RTL expansion of a MEM_REF that we handle as a BIT_FIELD_REF
whose base was allocated to a register but which was originally
aligned to allow a larger load not trapping. While probably UB
in C the vectorizer creates aligned accesses that might overread
a (static) allocation because it is then known not to trap.
PR middle-end/118684
* expr.cc (expand_expr_real_1): When expanding a reference
based on a register and we end up needing a MEM make sure
that's aligned as the original reference required.
* gcc.dg/pr118684.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/expr.cc | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr118684.c | 12 |
2 files changed, 17 insertions, 1 deletions
diff --git a/gcc/expr.cc b/gcc/expr.cc index a06411e..95f41f6 100644 --- a/gcc/expr.cc +++ b/gcc/expr.cc @@ -12148,7 +12148,11 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode, and need be, put it there. */ else if (CONSTANT_P (op0) || (!MEM_P (op0) && must_force_mem)) { - memloc = assign_temp (TREE_TYPE (tem), 1, 1); + poly_int64 size; + if (!poly_int_tree_p (TYPE_SIZE_UNIT (TREE_TYPE (tem)), &size)) + size = max_int_size_in_bytes (TREE_TYPE (tem)); + memloc = assign_stack_local (TYPE_MODE (TREE_TYPE (tem)), size, + get_object_alignment (tem)); emit_move_insn (memloc, op0); op0 = memloc; clear_mem_expr = true; diff --git a/gcc/testsuite/gcc.dg/pr118684.c b/gcc/testsuite/gcc.dg/pr118684.c new file mode 100644 index 0000000..08cc24d --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr118684.c @@ -0,0 +1,12 @@ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +typedef int v4si __attribute__((vector_size(16))); +v4si x; +int main () +{ + int b __attribute__((aligned(16))); + b = 0; + x = *(v4si *)&b; + return 0; +} |