From 7548c1be3a1ed1b10f5752a41d8efa3a3dfe01ac Mon Sep 17 00:00:00 2001
From: Wei Guozhi <carrot@google.com>
Date: Thu, 8 Apr 2010 09:27:44 +0000
Subject: [PATCH] re PR target/41653 (not optimal result for multiplication
 with constant when -Os is specified)

        PR target/41653
        * config/arm/arm.c (thumb1_size_rtx_costs): New function.
        (arm_size_rtx_costs): Call the new function when optimized for size.

From-SVN: r158110
---
 gcc/ChangeLog        |   6 ++
 gcc/config/arm/arm.c | 127 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 131 insertions(+), 2 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7e08006de17..94860fafabb 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-04-08  Wei Guozhi  <carrot@google.com>
+
+	PR target/41653
+	* config/arm/arm.c (thumb1_size_rtx_costs): New function.
+	(arm_size_rtx_costs): Call the new function when optimized for size.
+
 2010-04-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR debug/43670
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 84dd8fa972b..242ead5f027 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -6884,6 +6884,130 @@ arm_rtx_costs_1 (rtx x, enum rtx_code outer, int* total, bool speed)
     }
 }
 
+/* Estimates the size cost of thumb1 instructions.
+   For now most of the code is copied from thumb1_rtx_costs. We need more
+   fine grain tuning when we have more related test cases.  */
+static inline int
+thumb1_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer)
+{
+  enum machine_mode mode = GET_MODE (x);
+
+  switch (code)
+    {
+    case ASHIFT:
+    case ASHIFTRT:
+    case LSHIFTRT:
+    case ROTATERT:
+    case PLUS:
+    case MINUS:
+    case COMPARE:
+    case NEG:
+    case NOT:
+      return COSTS_N_INSNS (1);
+
+    case MULT:
+      if (GET_CODE (XEXP (x, 1)) == CONST_INT)
+        {
+          /* Thumb1 mul instruction can't operate on const. We must Load it
+             into a register first.  */
+          int const_size = thumb1_size_rtx_costs (XEXP (x, 1), CONST_INT, SET);
+          return COSTS_N_INSNS (1) + const_size;
+        }
+      return COSTS_N_INSNS (1);
+
+    case SET:
+      return (COSTS_N_INSNS (1)
+              + 4 * ((GET_CODE (SET_SRC (x)) == MEM)
+                     + GET_CODE (SET_DEST (x)) == MEM));
+
+    case CONST_INT:
+      if (outer == SET)
+        {
+          if ((unsigned HOST_WIDE_INT) INTVAL (x) < 256)
+            return 0;
+          if (thumb_shiftable_const (INTVAL (x)))
+            return COSTS_N_INSNS (2);
+          return COSTS_N_INSNS (3);
+        }
+      else if ((outer == PLUS || outer == COMPARE)
+               && INTVAL (x) < 256 && INTVAL (x) > -256)
+        return 0;
+      else if ((outer == IOR || outer == XOR || outer == AND)
+               && INTVAL (x) < 256 && INTVAL (x) >= -256)
+        return COSTS_N_INSNS (1);
+      else if (outer == AND)
+        {
+          int i;
+          /* This duplicates the tests in the andsi3 expander.  */
+          for (i = 9; i <= 31; i++)
+            if ((((HOST_WIDE_INT) 1) << i) - 1 == INTVAL (x)
+                || (((HOST_WIDE_INT) 1) << i) - 1 == ~INTVAL (x))
+              return COSTS_N_INSNS (2);
+        }
+      else if (outer == ASHIFT || outer == ASHIFTRT
+               || outer == LSHIFTRT)
+        return 0;
+      return COSTS_N_INSNS (2);
+
+    case CONST:
+    case CONST_DOUBLE:
+    case LABEL_REF:
+    case SYMBOL_REF:
+      return COSTS_N_INSNS (3);
+
+    case UDIV:
+    case UMOD:
+    case DIV:
+    case MOD:
+      return 100;
+
+    case TRUNCATE:
+      return 99;
+
+    case AND:
+    case XOR:
+    case IOR:
+      /* XXX guess.  */
+      return 8;
+
+    case MEM:
+      /* XXX another guess.  */
+      /* Memory costs quite a lot for the first word, but subsequent words
+         load at the equivalent of a single insn each.  */
+      return (10 + 4 * ((GET_MODE_SIZE (mode) - 1) / UNITS_PER_WORD)
+              + ((GET_CODE (x) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (x))
+                 ? 4 : 0));
+
+    case IF_THEN_ELSE:
+      /* XXX a guess.  */
+      if (GET_CODE (XEXP (x, 1)) == PC || GET_CODE (XEXP (x, 2)) == PC)
+        return 14;
+      return 2;
+
+    case ZERO_EXTEND:
+      /* XXX still guessing.  */
+      switch (GET_MODE (XEXP (x, 0)))
+        {
+          case QImode:
+            return (1 + (mode == DImode ? 4 : 0)
+                    + (GET_CODE (XEXP (x, 0)) == MEM ? 10 : 0));
+
+          case HImode:
+            return (4 + (mode == DImode ? 4 : 0)
+                    + (GET_CODE (XEXP (x, 0)) == MEM ? 10 : 0));
+
+          case SImode:
+            return (1 + (GET_CODE (XEXP (x, 0)) == MEM ? 10 : 0));
+
+          default:
+            return 99;
+        }
+
+    default:
+      return 99;
+    }
+}
+
 /* RTX costs when optimizing for size.  */
 static bool
 arm_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer_code,
@@ -6892,8 +7016,7 @@ arm_size_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer_code,
   enum machine_mode mode = GET_MODE (x);
   if (TARGET_THUMB1)
     {
-      /* XXX TBD.  For now, use the standard costs.  */
-      *total = thumb1_rtx_costs (x, code, outer_code);
+      *total = thumb1_size_rtx_costs (x, code, outer_code);
       return true;
     }
 
-- 
2.30.2