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| author | Kyrylo Tkachov <kyrylo.tkachov@arm.com> | 2016-03-03 17:25:43 +0000 |
|---|---|---|
| committer | Kyrylo Tkachov <ktkachov@gcc.gnu.org> | 2016-03-03 17:25:43 +0000 |
| commit | 0ba3bfa2b04d68ab9c727bdf1331b87919084d7c (patch) | |
| tree | fbf3a3d4d054812982ca8f98dfaa6f1efc5efe20 | |
| parent | 97ecdb46b1261d34e015df1f6eff20e069ca9bbf (diff) | |
| download | gcc-0ba3bfa2b04d68ab9c727bdf1331b87919084d7c.zip gcc-0ba3bfa2b04d68ab9c727bdf1331b87919084d7c.tar.gz gcc-0ba3bfa2b04d68ab9c727bdf1331b87919084d7c.tar.bz2 | |
[ARM] PR rtl-optimization/69904: Disallow copying/duplicating of load-exclusive operations
PR rtl-optimization/69904
* config/arm/arm.c (arm_cannot_copy_insn_p):
Return true for load-exclusive instructions.
* gcc.target/arm/pr69904.c: New test.
From-SVN: r233941
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/config/arm/arm.c | 20 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/arm/pr69904.c | 24 |
4 files changed, 54 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index fb5e396..9ae5500 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2016-03-03 Kyrylo Tkachov <kyrylo.tkachov@arm.com> + + PR rtl-optimization/69904 + * config/arm/arm.c (arm_cannot_copy_insn_p): + Return true for load-exclusive instructions. + 2016-03-03 Jakub Jelinek <jakub@redhat.com> PR target/70021 diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index 9489343..c868490 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -13263,7 +13263,11 @@ tls_mentioned_p (rtx x) } } -/* Must not copy any rtx that uses a pc-relative address. */ +/* Must not copy any rtx that uses a pc-relative address. + Also, disallow copying of load-exclusive instructions that + may appear after splitting of compare-and-swap-style operations + so as to prevent those loops from being transformed away from their + canonical forms (see PR 69904). */ static bool arm_cannot_copy_insn_p (rtx_insn *insn) @@ -13282,6 +13286,20 @@ arm_cannot_copy_insn_p (rtx_insn *insn) || XINT (x, 1) == UNSPEC_PIC_UNIFIED)) return true; } + + rtx set = single_set (insn); + if (set) + { + rtx src = SET_SRC (set); + if (GET_CODE (src) == ZERO_EXTEND) + src = XEXP (src, 0); + + /* Catch the load-exclusive and load-acquire operations. */ + if (GET_CODE (src) == UNSPEC_VOLATILE + && (XINT (src, 1) == VUNSPEC_LL + || XINT (src, 1) == VUNSPEC_LAX)) + return true; + } return false; } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 5ffe64f..a3592de 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-03-03 Kyrylo Tkachov <kyrylo.tkachov@arm.com> + + PR rtl-optimization/69904 + * gcc.target/arm/pr69904.c: New test. + 2016-03-03 Jakub Jelinek <jakub@redhat.com> PR target/70021 diff --git a/gcc/testsuite/gcc.target/arm/pr69904.c b/gcc/testsuite/gcc.target/arm/pr69904.c new file mode 100644 index 0000000..24fe844 --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/pr69904.c @@ -0,0 +1,24 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -marm" } */ +/* { dg-require-effective-target arm_arch_v7a_ok } */ +/* { dg-add-options arm_arch_v7a } */ + +/* Make sure that RTL optimizers don't do any unexpected transformations + on the compare_exchange loop. */ + +#include <stdatomic.h> + +atomic_uint foo; +atomic_uint bar; +int glob; + +int +main (void) +{ + glob = atomic_compare_exchange_strong (&foo, &bar, 0); + return glob; +} + +/* { dg-final { scan-assembler-times "dmb\tish" 2 } } */ +/* { dg-final { scan-assembler-times "ldrex\t" 1 } } */ +/* { dg-final { scan-assembler-times "strex\t" 1 } } */ |