[committed] MIPS: Implement TARGET_INSN_COSTS

[YunQiang Su <syq@gcc.gnu.org>]

When combine some instructions, the generic `rtx_cost`
may over estimate the cost of result RTL, due to that
the RTL may be quite complex and `rtx_cost` has no
information that this RTL can be convert to simple
hardware instruction(s).

In this case, Let's use `insn_count * perf_ratio` to
estimate the cost if both of them are available.
Otherwise fallback to pattern_cost.

When non-speed, Let's use the length as cost.

gcc

	* config/mips/mips.cc (mips_insn_cost): New function.

gcc/testsuite

	* gcc.target/mips/data-sym-multi-pool.c: Skip Os or -O0.
---
 gcc/config/mips/mips.cc                       | 33 +++++++++++++++++++
 .../gcc.target/mips/data-sym-multi-pool.c     |  2 +-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc
index 3131749d6ea..46b7d9b64ff 100644
--- a/gcc/config/mips/mips.cc
+++ b/gcc/config/mips/mips.cc
@@ -4170,6 +4170,37 @@ mips_set_reg_reg_cost (machine_mode mode)
     }
 }
 
+/* Implement TARGET_INSN_COSTS.  */
+
+static int
+mips_insn_cost (rtx_insn *x, bool speed)
+{
+  int cost;
+  int count;
+  int ratio;
+
+  if (recog_memoized (x) < 0
+      && GET_CODE (PATTERN (x)) != ASM_INPUT
+      && asm_noperands (PATTERN (x)) < 0)
+    goto pattern_cost;
+
+  /* FIXME: return get_attr_length?  More tests may be needed.  */
+  if (!speed)
+    goto pattern_cost;
+
+  count = get_attr_insn_count (x);
+  ratio = get_attr_perf_ratio (x);
+  cost = count * ratio;
+  if (cost > 0)
+    return cost;
+
+pattern_cost:
+  cost = pattern_cost (PATTERN (x), speed);
+  /* If the cost is zero, then it's likely a complex insn.
+     FIXME: Return COSTS_N_INSNS (2)?  More tests are needed.  */
+  return cost;
+}
+
 /* Implement TARGET_RTX_COSTS.  */
 
 static bool
@@ -23069,6 +23100,8 @@ mips_bit_clear_p (enum machine_mode mode, unsigned HOST_WIDE_INT m)
 #define TARGET_RTX_COSTS mips_rtx_costs
 #undef TARGET_ADDRESS_COST
 #define TARGET_ADDRESS_COST mips_address_cost
+#undef  TARGET_INSN_COST
+#define TARGET_INSN_COST mips_insn_cost
 
 #undef TARGET_NO_SPECULATION_IN_DELAY_SLOTS_P
 #define TARGET_NO_SPECULATION_IN_DELAY_SLOTS_P mips_no_speculation_in_delay_slots_p
diff --git a/gcc/testsuite/gcc.target/mips/data-sym-multi-pool.c b/gcc/testsuite/gcc.target/mips/data-sym-multi-pool.c
index 3cf2d4f0248..8643095ff9f 100644
--- a/gcc/testsuite/gcc.target/mips/data-sym-multi-pool.c
+++ b/gcc/testsuite/gcc.target/mips/data-sym-multi-pool.c
@@ -1,6 +1,6 @@
 /* { dg-do compile } */
 /* { dg-options "-mips16 -mcode-readable=yes -fno-tree-vrp -fno-tree-dominator-opts" } */
-/* { dg-skip-if "per-function expected output" { *-*-* } { "-flto" } { "" } } */
+/* { dg-skip-if "per-function expected output" { *-*-* } { "-flto" "-O0" "-Os" } { "" } } */
 
 /* This testcase generates multiple constant pools within a function body.  */
 
-- 
2.39.2