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From: "sje at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/65315] New: incorrect alignment of local variable with aligned attribute Date: Wed, 04 Mar 2015 18:38:00 -0000 [thread overview] Message-ID: <bug-65315-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65315 Bug ID: 65315 Summary: incorrect alignment of local variable with aligned attribute Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: sje at gcc dot gnu.org Created attachment 34953 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34953&action=edit Test case When GCC has multiple local variables with different aligned attributes on them, it creates an aligned block of space aligned to the least aligned variable instead of the most aligned variable. In the attached program, when run on MIPS, GCC is creating a 32 byte aligned block of memory for foo1, foo3, and foo4 and a 128 byte aligned memory block for foo2. foo3 and foo4 should have 128 byte aligned memory. I thought the problem was in stack_var_cmp where it checks the alignment of two variables and returns '(int) largeb - (int) largea' to sort the variables based on their alignment but when I swapped the two arguments I got an ICE in expand_stack_vars [gcc_assert (large_base != NULL);]. It also tried changing: large_align = stack_vars[stack_vars_sorted[0]].alignb * BITS_PER_UNIT; to large_align = stack_vars[stack_vars_sorted[n-1]].alignb * BITS_PER_UNIT; but that caused the same ICE. It may be that we need a loop to check the alignment of each variable.
next reply other threads:[~2015-03-04 18:38 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-04 18:38 sje at gcc dot gnu.org [this message] 2015-03-04 18:58 ` [Bug middle-end/65315] " sje at gcc dot gnu.org 2015-03-05 16:34 ` sje at gcc dot gnu.org 2015-10-21 23:43 ` sje at gcc dot gnu.org
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