[PATCH 5/5] rs6000: Implement insn_cost hook

[Segher Boessenkool <segher at kernel dot crashing dot org>]

This is a pretty minimalistic implementation of the insn_cost hook: it
just counts how many machine instructions will be generated.  Some
improvements are needed: loads should get extra cost; some instructions
like mul and div should be more expensive than others; and it exposes
some suboptimalities in our machine description files.  Still, good
enough for most testing.

---
 gcc/config/rs6000/rs6000.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index a7d2e7e..b4fda69 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1761,6 +1761,8 @@ static const struct attribute_spec rs6000_attribute_table[] =
 #define TARGET_RTX_COSTS rs6000_rtx_costs
 #undef TARGET_ADDRESS_COST
 #define TARGET_ADDRESS_COST hook_int_rtx_mode_as_bool_0
+#undef TARGET_INSN_COST
+#define TARGET_INSN_COST rs6000_insn_cost
 
 #undef TARGET_INIT_DWARF_REG_SIZES_EXTRA
 #define TARGET_INIT_DWARF_REG_SIZES_EXTRA rs6000_init_dwarf_reg_sizes_extra
@@ -34521,6 +34523,18 @@ rs6000_debug_rtx_costs (rtx x, machine_mode mode, int outer_code,
   return ret;
 }
 
+static int
+rs6000_insn_cost (rtx_insn *insn, bool speed)
+{
+  if (recog_memoized (insn) < 0)
+    return 0;
+
+  if (!speed)
+    return get_attr_length (insn);
+
+  return COSTS_N_INSNS (get_attr_length (insn) / 4);
+}
+
 /* Debug form of ADDRESS_COST that is selected if -mdebug=cost.  */
 
 static int
-- 
1.9.3