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author | Kyrylo Tkachov <kyrylo.tkachov@arm.com> | 2022-11-30 17:38:16 +0000 |
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committer | Kyrylo Tkachov <kyrylo.tkachov@arm.com> | 2022-11-30 17:38:16 +0000 |
commit | cbdffae5745327b0e5eb887afc512daf34b049b1 (patch) | |
tree | ff8575e5bfb0fbd897da1a0ad1b614b0990bdb5b /libcpp | |
parent | 031d3f095520f0e1ee03e29b7ad5067c2a3f96e0 (diff) | |
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aarch64: Specify that FEAT_MOPS sequences clobber CC
According to the architecture pseudocode the FEAT_MOPS sequences overwrite the NZCV flags
as par of their operation, so GCC needs to model that in the relevant RTL patterns.
For the testcase:
void g();
void foo (int a, size_t N, char *__restrict__ in,
char *__restrict__ out)
{
if (a != 3)
__builtin_memcpy (out, in, N);
if (a > 3)
g ();
}
we will currently generate:
foo:
cmp w0, 3
bne .L6
.L1:
ret
.L6:
cpyfp [x3]!, [x2]!, x1!
cpyfm [x3]!, [x2]!, x1!
cpyfe [x3]!, [x2]!, x1!
ble .L1 // Flags reused after CPYF* sequence
b g
This is wrong as the result of cmp needs to be recalculated after the MOPS sequence.
With this patch we'll insert a "cmp w0, 3" before the ble, similar to what clang does.
Bootstrapped and tested on aarch64-none-linux-gnu.
Pushing to trunk and to the GCC 12 branch after some baking time.
gcc/ChangeLog:
* config/aarch64/aarch64.md (aarch64_cpymemdi): Specify clobber of CC reg.
(*aarch64_cpymemdi): Likewise.
(aarch64_movmemdi): Likewise.
(aarch64_setmemdi): Likewise.
(*aarch64_setmemdi): Likewise.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/mops_5.c: New test.
* gcc.target/aarch64/mops_6.c: Likewise.
* gcc.target/aarch64/mops_7.c: Likewise.
Diffstat (limited to 'libcpp')
0 files changed, 0 insertions, 0 deletions