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| author | Wilco Dijkstra <wdijkstr@arm.com> | 2017-09-05 13:27:58 +0000 |
|---|---|---|
| committer | Wilco Dijkstra <wilco@gcc.gnu.org> | 2017-09-05 13:27:58 +0000 |
| commit | ae85ad3a95d6df3c4131d02fd327809a29d10b33 (patch) | |
| tree | 7280c7e1c75597c2c29f62ff781b46e1369249c9 /gcc/builtins.c | |
| parent | 54c430044ba9a35a590e591108b184535eba5763 (diff) | |
| download | gcc-ae85ad3a95d6df3c4131d02fd327809a29d10b33.zip gcc-ae85ad3a95d6df3c4131d02fd327809a29d10b33.tar.gz gcc-ae85ad3a95d6df3c4131d02fd327809a29d10b33.tar.bz2 | |
Improve alloca alignment
This patch improves alloca alignment. Currently alloca reserves
too much space as it aligns twice, and generates unnecessary stack
alignment code.
When the requested alignment is lower than the stack alignment, no
extra alignment is needed. If the requested alignment is higher,
we need to increase the size by the difference of the requested
alignment and the stack alignment. As a result, the alloca alignment
is exactly as expected:
alloca (16):
sub sp, sp, #16
mov x1, sp
alloca (x):
add x0, x0, 15
and x0, x0, -16
sub sp, sp, x0
mov x0, sp
__builtin_alloca_with_align (x, 512):
add x0, x0, 63
and x0, x0, -16
sub sp, sp, x0
add x0, sp, 63
and x0, x0, -64
gcc/
* explow.c (get_dynamic_stack_size): Improve dynamic alignment.
From-SVN: r251713
Diffstat (limited to 'gcc/builtins.c')
0 files changed, 0 insertions, 0 deletions