| Upstream-Status: Backport |
| Signed-off-by: Ross Burton <ross.burton@arm.com> |
| |
| From fd2ec4542fd2975e6d3f2f1c1a2639945a84f9e1 Mon Sep 17 00:00:00 2001 |
| From: Jakub Jelinek <jakub@redhat.com> |
| Date: Mon, 3 Aug 2020 22:55:28 +0200 |
| Subject: [PATCH] aarch64: Fix up __aarch64_cas16_acq_rel fallback |
| |
| As mentioned in the PR, the fallback path when LSE is unavailable writes |
| incorrect registers to the memory if the previous content compares equal |
| to x0, x1 - it writes copy of x0, x1 from the start of function, but it |
| should write x2, x3. |
| |
| 2020-08-03 Jakub Jelinek <jakub@redhat.com> |
| |
| PR target/96402 |
| * config/aarch64/lse.S (__aarch64_cas16_acq_rel): Use x2, x3 instead |
| of x(tmp0), x(tmp1) in STXP arguments. |
| |
| * gcc.target/aarch64/pr96402.c: New test. |
| |
| (cherry picked from commit 90b43856fdff7d96d93d22970eca8a86c56e0ddc) |
| --- |
| gcc/testsuite/gcc.target/aarch64/pr96402.c | 16 ++++++++++++++++ |
| libgcc/config/aarch64/lse.S | 2 +- |
| 2 files changed, 17 insertions(+), 1 deletion(-) |
| create mode 100644 gcc/testsuite/gcc.target/aarch64/pr96402.c |
| |
| diff --git a/gcc/testsuite/gcc.target/aarch64/pr96402.c b/gcc/testsuite/gcc.target/aarch64/pr96402.c |
| new file mode 100644 |
| index 00000000000..fa2dddfac15 |
| --- /dev/null |
| +++ b/gcc/testsuite/gcc.target/aarch64/pr96402.c |
| @@ -0,0 +1,16 @@ |
| +/* PR target/96402 */ |
| +/* { dg-do run { target int128 } } */ |
| +/* { dg-options "-moutline-atomics" } */ |
| + |
| +int |
| +main () |
| +{ |
| + __int128 a = 0; |
| + __sync_val_compare_and_swap (&a, (__int128) 0, (__int128) 1); |
| + if (a != 1) |
| + __builtin_abort (); |
| + __sync_val_compare_and_swap (&a, (__int128) 1, (((__int128) 0xdeadbeeffeedbac1ULL) << 64) | 0xabadcafe00c0ffeeULL); |
| + if (a != ((((__int128) 0xdeadbeeffeedbac1ULL) << 64) | 0xabadcafe00c0ffeeULL)) |
| + __builtin_abort (); |
| + return 0; |
| +} |
| diff --git a/libgcc/config/aarch64/lse.S b/libgcc/config/aarch64/lse.S |
| index 64691c601c1..c8fbfbce4fd 100644 |
| --- a/libgcc/config/aarch64/lse.S |
| +++ b/libgcc/config/aarch64/lse.S |
| @@ -203,7 +203,7 @@ STARTFN NAME(cas) |
| cmp x0, x(tmp0) |
| ccmp x1, x(tmp1), #0, eq |
| bne 1f |
| - STXP w(tmp2), x(tmp0), x(tmp1), [x4] |
| + STXP w(tmp2), x2, x3, [x4] |
| cbnz w(tmp2), 0b |
| 1: ret |
| |
| -- |
| 2.26.2 |
| |