@@ -63,6 +63,7 @@ static const char *nios2_unspec_reloc_name (int);
static void nios2_register_builtin_fndecl (unsigned, tree);
static rtx nios2_ldst_parallel (bool, bool, bool, rtx, int,
unsigned HOST_WIDE_INT, bool);
+static int nios2_address_cost (rtx, machine_mode, addr_space_t, bool);
/* Threshold for data being put into the small data/bss area, instead
of the normal data area (references to the small data/bss area take
@@ -1502,29 +1503,25 @@ nios2_simple_const_p (const_rtx cst)
cost has been computed, and false if subexpressions should be
scanned. In either case, *TOTAL contains the cost result. */
static bool
-nios2_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
- int outer_code ATTRIBUTE_UNUSED,
- int opno ATTRIBUTE_UNUSED,
- int *total, bool speed ATTRIBUTE_UNUSED)
+nios2_rtx_costs (rtx x, machine_mode mode,
+ int outer_code,
+ int opno,
+ int *total, bool speed)
{
int code = GET_CODE (x);
switch (code)
{
case CONST_INT:
- if (INTVAL (x) == 0)
+ if (INTVAL (x) == 0 || nios2_simple_const_p (x))
{
*total = COSTS_N_INSNS (0);
return true;
}
- else if (nios2_simple_const_p (x))
- {
- *total = COSTS_N_INSNS (2);
- return true;
- }
else
{
- *total = COSTS_N_INSNS (4);
+ /* High + lo_sum. */
+ *total = COSTS_N_INSNS (1);
return true;
}
@@ -1532,10 +1529,30 @@ nios2_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
case SYMBOL_REF:
case CONST:
case CONST_DOUBLE:
- {
- *total = COSTS_N_INSNS (4);
- return true;
- }
+ if (gprel_constant_p (x))
+ {
+ *total = COSTS_N_INSNS (1);
+ return true;
+ }
+ else
+ {
+ /* High + lo_sum. */
+ *total = COSTS_N_INSNS (1);
+ return true;
+ }
+
+ case HIGH:
+ {
+ /* This is essentially a constant. */
+ *total = COSTS_N_INSNS (0);
+ return true;
+ }
+
+ case LO_SUM:
+ {
+ *total = COSTS_N_INSNS (0);
+ return true;
+ }
case AND:
{
@@ -1549,29 +1566,83 @@ nios2_rtx_costs (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
return false;
}
+ /* For insns that have an execution latency (3 cycles), don't
+ penalize by the full amount since we can often schedule
+ to avoid it. */
case MULT:
{
- *total = COSTS_N_INSNS (1);
+ if (!TARGET_HAS_MUL)
+ *total = COSTS_N_INSNS (5); /* Guess? */
+ else if (speed)
+ *total = COSTS_N_INSNS (2); /* Latency adjustment. */
+ else
+ *total = COSTS_N_INSNS (1);
return false;
}
- case SIGN_EXTEND:
+
+ case DIV:
{
- *total = COSTS_N_INSNS (3);
+ if (!TARGET_HAS_DIV)
+ *total = COSTS_N_INSNS (5); /* Guess? */
+ else if (speed)
+ *total = COSTS_N_INSNS (2); /* Latency adjustment. */
+ else
+ *total = COSTS_N_INSNS (1);
return false;
}
- case ZERO_EXTEND:
+
+ case ASHIFT:
+ case ASHIFTRT:
+ case LSHIFTRT:
+ case ROTATE:
{
- *total = COSTS_N_INSNS (1);
+ if (!speed)
+ *total = COSTS_N_INSNS (1);
+ else
+ *total = COSTS_N_INSNS (2); /* Latency adjustment. */
return false;
}
+
+ case ZERO_EXTRACT:
+ if (TARGET_HAS_BMX)
+ {
+ *total = COSTS_N_INSNS (1);
+ return true;
+ }
+ return false;
- case ZERO_EXTRACT:
- if (TARGET_HAS_BMX)
+ case SIGN_EXTEND:
+ {
+ if (MEM_P (XEXP (x, 0)))
+ *total = COSTS_N_INSNS (1);
+ else
+ *total = COSTS_N_INSNS (3);
+ return false;
+ }
+
+ case MEM:
{
- *total = COSTS_N_INSNS (1);
- return true;
+ rtx addr = XEXP (x, 0);
+
+ /* Account for cost of different addressing modes. */
+ *total = nios2_address_cost (addr, mode, ADDR_SPACE_GENERIC, speed);
+
+ if (outer_code == SET && opno == 0)
+ /* Stores execute in 1 cycle accounted for by
+ the outer SET. */
+ ;
+ else if (outer_code == SET || outer_code == SIGN_EXTEND
+ || outer_code == ZERO_EXTEND)
+ /* Latency adjustment. */
+ {
+ if (speed)
+ *total += COSTS_N_INSNS (1);
+ }
+ else
+ /* This is going to have to be split into a load. */
+ *total += COSTS_N_INSNS (speed ? 2 : 1);
+ return true;
}
- return false;
default:
return false;
@@ -2149,6 +2220,37 @@ nios2_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED,
return false;
}
+/* Implement TARGET_ADDRESS_COST.
+ Experimentation has shown that we get better code by penalizing the
+ the (plus reg symbolic_constant) and (plus reg (const ...)) forms
+ but giving (plus reg symbol_ref) address modes the same cost as those
+ that don't require splitting. Also, from a theoretical point of view:
+ - This is in line with the recommendation in the GCC internals
+ documentation to make address forms involving multiple
+ registers more expensive than single-register forms.
+ - OTOH it still encourages fwprop1 to propagate constants into
+ address expressions more aggressively.
+ - We should discourage splitting (symbol + offset) into hi/lo pairs
+ to allow CSE'ing the symbol when it's used with more than one offset,
+ but not so heavily as to avoid this addressing mode at all. */
+static int
+nios2_address_cost (rtx address,
+ machine_mode mode ATTRIBUTE_UNUSED,
+ addr_space_t as ATTRIBUTE_UNUSED,
+ bool speed ATTRIBUTE_UNUSED)
+{
+ if (nios2_plus_symbolic_constant_p (address))
+ return COSTS_N_INSNS (1);
+ if (nios2_symbolic_constant_p (address))
+ {
+ if (GET_CODE (address) == CONST)
+ return COSTS_N_INSNS (1);
+ else
+ return COSTS_N_INSNS (0);
+ }
+ return COSTS_N_INSNS (0);
+}
+
/* Return true if X is a MEM whose address expression involves a symbolic
constant. */
bool
@@ -2455,8 +2557,16 @@ nios2_legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED,
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
+ /* Target-independent code turns (exp + constant) into plain
+ register indirect. Although subsequent optimization passes will
+ eventually sort that out, ivopts uses the unoptimized form for
+ computing its cost model, so we get better results by generating
+ the correct form from the start. */
+ if (nios2_valid_addr_offset_p (op1))
+ return gen_rtx_PLUS (Pmode, force_reg (Pmode, op0), copy_rtx (op1));
+
/* We may need to split symbolic constants now. */
- if (nios2_symbolic_constant_p (op1))
+ else if (nios2_symbolic_constant_p (op1))
{
if (nios2_symbolic_constant_allowed ())
return gen_rtx_PLUS (Pmode, force_reg (Pmode, op0), copy_rtx (op1));
@@ -5318,6 +5428,9 @@ nios2_adjust_reg_alloc_order (void)
#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS nios2_rtx_costs
+#undef TARGET_ADDRESS_COST
+#define TARGET_ADDRESS_COST nios2_address_cost
+
#undef TARGET_HAVE_TLS
#define TARGET_HAVE_TLS TARGET_LINUX_ABI