diff options
Diffstat (limited to 'gcc/config/arm/arm.c')
| -rw-r--r-- | gcc/config/arm/arm.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index 371528b0405..8f6679ed262 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -13233,7 +13233,11 @@ 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) @@ -13252,6 +13256,20 @@ 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; } |