/* Expand the basic unary and binary arithmetic operations, for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
- 2011 Free Software Foundation, Inc.
+ 2011, 2012 Free Software Foundation, Inc.
This file is part of GCC.
return NULL_RTX;
}
+/* This function tries to implement an atomic test-and-set operation
+ using the atomic_test_and_set instruction pattern. A boolean value
+ is returned from the operation, using TARGET if possible. */
+
#ifndef HAVE_atomic_test_and_set
#define HAVE_atomic_test_and_set 0
-#define gen_atomic_test_and_set(x,y,z) (gcc_unreachable (), NULL_RTX)
+#define CODE_FOR_atomic_test_and_set CODE_FOR_nothing
#endif
+static rtx
+maybe_emit_atomic_test_and_set (rtx target, rtx mem, enum memmodel model)
+{
+ enum machine_mode pat_bool_mode;
+ struct expand_operand ops[3];
+
+ if (!HAVE_atomic_test_and_set)
+ return NULL_RTX;
+
+ /* While we always get QImode from __atomic_test_and_set, we get
+ other memory modes from __sync_lock_test_and_set. Note that we
+ use no endian adjustment here. This matches the 4.6 behavior
+ in the Sparc backend. */
+ gcc_checking_assert
+ (insn_data[CODE_FOR_atomic_test_and_set].operand[1].mode == QImode);
+ if (GET_MODE (mem) != QImode)
+ mem = adjust_address_nv (mem, QImode, 0);
+
+ pat_bool_mode = insn_data[CODE_FOR_atomic_test_and_set].operand[0].mode;
+ create_output_operand (&ops[0], target, pat_bool_mode);
+ create_fixed_operand (&ops[1], mem);
+ create_integer_operand (&ops[2], model);
+
+ if (maybe_expand_insn (CODE_FOR_atomic_test_and_set, 3, ops))
+ return ops[0].value;
+ return NULL_RTX;
+}
+
/* This function expands the legacy _sync_lock test_and_set operation which is
generally an atomic exchange. Some limited targets only allow the
constant 1 to be stored. This is an ACQUIRE operation.
/* Try an atomic_exchange first. */
ret = maybe_emit_atomic_exchange (target, mem, val, MEMMODEL_ACQUIRE);
+ if (ret)
+ return ret;
- if (!ret)
- ret = maybe_emit_sync_lock_test_and_set (target, mem, val,
- MEMMODEL_ACQUIRE);
- if (!ret)
- ret = maybe_emit_compare_and_swap_exchange_loop (target, mem, val);
+ ret = maybe_emit_sync_lock_test_and_set (target, mem, val, MEMMODEL_ACQUIRE);
+ if (ret)
+ return ret;
+
+ ret = maybe_emit_compare_and_swap_exchange_loop (target, mem, val);
+ if (ret)
+ return ret;
/* If there are no other options, try atomic_test_and_set if the value
being stored is 1. */
- if (!ret && val == const1_rtx && HAVE_atomic_test_and_set)
- {
- ret = gen_atomic_test_and_set (target, mem, GEN_INT (MEMMODEL_ACQUIRE));
- emit_insn (ret);
- }
+ if (val == const1_rtx)
+ ret = maybe_emit_atomic_test_and_set (target, mem, MEMMODEL_ACQUIRE);
return ret;
}
expand_atomic_test_and_set (rtx target, rtx mem, enum memmodel model)
{
enum machine_mode mode = GET_MODE (mem);
- rtx ret = NULL_RTX;
+ rtx ret, trueval, subtarget;
- if (target == NULL_RTX)
- target = gen_reg_rtx (mode);
+ ret = maybe_emit_atomic_test_and_set (target, mem, model);
+ if (ret)
+ return ret;
- if (HAVE_atomic_test_and_set)
+ /* Be binary compatible with non-default settings of trueval, and different
+ cpu revisions. E.g. one revision may have atomic-test-and-set, but
+ another only has atomic-exchange. */
+ if (targetm.atomic_test_and_set_trueval == 1)
{
- ret = gen_atomic_test_and_set (target, mem, GEN_INT (MEMMODEL_ACQUIRE));
- emit_insn (ret);
- return ret;
+ trueval = const1_rtx;
+ subtarget = target ? target : gen_reg_rtx (mode);
+ }
+ else
+ {
+ trueval = gen_int_mode (targetm.atomic_test_and_set_trueval, mode);
+ subtarget = gen_reg_rtx (mode);
}
- /* If there is no test and set, try exchange, then a compare_and_swap loop,
- then __sync_test_and_set. */
- ret = maybe_emit_atomic_exchange (target, mem, const1_rtx, model);
+ /* Try the atomic-exchange optab... */
+ ret = maybe_emit_atomic_exchange (subtarget, mem, trueval, model);
+ /* ... then an atomic-compare-and-swap loop ... */
if (!ret)
- ret = maybe_emit_compare_and_swap_exchange_loop (target, mem, const1_rtx);
+ ret = maybe_emit_compare_and_swap_exchange_loop (subtarget, mem, trueval);
+ /* ... before trying the vaguely defined legacy lock_test_and_set. */
if (!ret)
- ret = maybe_emit_sync_lock_test_and_set (target, mem, const1_rtx, model);
+ ret = maybe_emit_sync_lock_test_and_set (subtarget, mem, trueval, model);
- if (ret)
- return ret;
+ /* Recall that the legacy lock_test_and_set optab was allowed to do magic
+ things with the value 1. Thus we try again without trueval. */
+ if (!ret && targetm.atomic_test_and_set_trueval != 1)
+ ret = maybe_emit_sync_lock_test_and_set (subtarget, mem, const1_rtx, model);
- /* Failing all else, assume a single threaded environment and simply perform
- the operation. */
- emit_move_insn (target, mem);
- emit_move_insn (mem, const1_rtx);
- return target;
+ /* Failing all else, assume a single threaded environment and simply
+ perform the operation. */
+ if (!ret)
+ {
+ emit_move_insn (subtarget, mem);
+ emit_move_insn (mem, trueval);
+ ret = subtarget;
+ }
+
+ /* Recall that have to return a boolean value; rectify if trueval
+ is not exactly one. */
+ if (targetm.atomic_test_and_set_trueval != 1)
+ ret = emit_store_flag_force (target, NE, ret, const0_rtx, mode, 0, 1);
+
+ return ret;
}
/* This function expands the atomic exchange operation:
/* Issue val = compare_and_swap (mem, 0, 0).
This may cause the occasional harmless store of 0 when the value is
already 0, but it seems to be OK according to the standards guys. */
- expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
- const0_rtx, false, model, model);
- return target;
+ if (expand_atomic_compare_and_swap (NULL, &target, mem, const0_rtx,
+ const0_rtx, false, model, model))
+ return target;
+ else
+ /* Otherwise there is no atomic load, leave the library call. */
+ return NULL_RTX;
}
/* Otherwise assume loads are atomic, and emit the proper barriers. */
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