Upstream-Status: Backport Signed-off-by: Ross Burton From fd2ec4542fd2975e6d3f2f1c1a2639945a84f9e1 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek 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 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