diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/optabs.c | 26 |
2 files changed, 22 insertions, 9 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index bf396f74a08..a5e907c6305 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2005-05-10 Richard Henderson <rth@redhat.com> + * optabs.c (expand_compare_and_swap_loop): Don't clobber old value + before comparing it for success. + +2005-05-10 Richard Henderson <rth@redhat.com> + * config/ia64/sync.md (sync_add<I48MODE>): Fix arguments for no return value pattern. diff --git a/gcc/optabs.c b/gcc/optabs.c index 3b3250aac3b..2955f7b3ad9 100644 --- a/gcc/optabs.c +++ b/gcc/optabs.c @@ -5625,24 +5625,27 @@ expand_compare_and_swap_loop (rtx mem, rtx old_reg, rtx new_reg, rtx seq) { enum machine_mode mode = GET_MODE (mem); enum insn_code icode; - rtx label, subtarget; + rtx label, cmp_reg, subtarget; /* The loop we want to generate looks like - old_reg = mem; + cmp_reg = mem; label: + old_reg = cmp_reg; seq; - old_reg = compare-and-swap(mem, old_reg, new_reg) - if (old_reg != new_reg) + cmp_reg = compare-and-swap(mem, old_reg, new_reg) + if (cmp_reg != old_reg) goto label; Note that we only do the plain load from memory once. Subsequent iterations use the value loaded by the compare-and-swap pattern. */ label = gen_label_rtx (); + cmp_reg = gen_reg_rtx (mode); - emit_move_insn (old_reg, mem); + emit_move_insn (cmp_reg, mem); emit_label (label); + emit_move_insn (old_reg, cmp_reg); if (seq) emit_insn (seq); @@ -5654,9 +5657,12 @@ expand_compare_and_swap_loop (rtx mem, rtx old_reg, rtx new_reg, rtx seq) { default: subtarget = expand_val_compare_and_swap_1 (mem, old_reg, new_reg, - old_reg, icode); + cmp_reg, icode); if (subtarget != NULL_RTX) - break; + { + gcc_assert (subtarget == cmp_reg); + break; + } /* FALLTHRU */ case CODE_FOR_nothing: @@ -5665,11 +5671,13 @@ expand_compare_and_swap_loop (rtx mem, rtx old_reg, rtx new_reg, rtx seq) return false; subtarget = expand_val_compare_and_swap_1 (mem, old_reg, new_reg, - old_reg, icode); + cmp_reg, icode); if (subtarget == NULL_RTX) return false; + if (subtarget != cmp_reg) + emit_move_insn (cmp_reg, subtarget); - emit_cmp_insn (subtarget, old_reg, EQ, const0_rtx, mode, true); + emit_cmp_insn (cmp_reg, old_reg, EQ, const0_rtx, mode, true); } /* ??? Mark this jump predicted not taken? */ |
