[PATCH, i386]: Improve constant RTX costs a bit

[Uros Bizjak]

2016-05-20  Uros Bizjak  <ubiz...@gmail.com>

    * gcc/config/i386/i386.c (ix86_rtx_costs) <case CONST_DOUBLE>:
    Use IS_STACK_MODE when calculating cost of standard 80387 constants.
    Fallthru to CONST_VECTOR case to calculate cost of standard SSE
    constants.
    <case CONST_WIDE_INT>: Calculate cost of (MEM (SYMBOL_REF)).
    (ix86_legitimate_constant_p): Use CASE_CONST_SCALAR_INT
    and CASE_CONST_ANY.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Committed to mainline SVN.

Uros.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index cecea11..26ec3cb 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -14864,8 +14864,7 @@ ix86_legitimate_constant_p (machine_mode mode, rtx x)
 #endif
       break;
 
-    case CONST_INT:
-    case CONST_WIDE_INT:
+    CASE_CONST_SCALAR_INT:
       switch (mode)
        {
        case TImode:
@@ -14900,18 +14899,16 @@ ix86_legitimate_constant_p (machine_mode mode, rtx x)
 static bool
 ix86_cannot_force_const_mem (machine_mode mode, rtx x)
 {
-  /* We can always put integral constants and vectors in memory.  */
+  /* We can put any immediate constant in memory.  */
   switch (GET_CODE (x))
     {
-    case CONST_INT:
-    case CONST_WIDE_INT:
-    case CONST_DOUBLE:
-    case CONST_VECTOR:
+    CASE_CONST_ANY:
       return false;
 
     default:
       break;
     }
+
   return !ix86_legitimate_constant_p (mode, x);
 }
 
@@ -44073,43 +44070,43 @@ ix86_rtx_costs (rtx x, machine_mode mode, int 
outer_code_i, int opno,
        *total = 0;
       return true;
 
-    case CONST_WIDE_INT:
-      *total = 0;
-      return true;
-
     case CONST_DOUBLE:
-      switch (standard_80387_constant_p (x))
+      if (TARGET_80387 && IS_STACK_MODE (mode))
+       switch (standard_80387_constant_p (x))
+         {
+         case -1:
+         case 0:
+           break;
+         case 1: /* 0.0 */
+           *total = 1;
+           return true;
+         default: /* Other constants */
+           *total = 2;
+           return true;
+         }
+      /* FALLTHRU */
+
+    case CONST_VECTOR:
+      switch (standard_sse_constant_p (x, mode))
        {
-       case 1: /* 0.0 */
-         *total = 1;
-         return true;
-       default: /* Other constants */
-         *total = 2;
-         return true;
        case 0:
-       case -1:
          break;
+       case 1:  /* 0: xor eliminates false dependency */
+         *total = 0;
+         return true;
+       default: /* -1: cmp contains false dependency */
+         *total = 1;
+         return true;
        }
-      if (SSE_FLOAT_MODE_P (mode))
-       {
-       case CONST_VECTOR:
-         switch (standard_sse_constant_p (x, mode))
-           {
-           case 0:
-             break;
-           case 1:  /* 0: xor eliminates false dependency */
-             *total = 0;
-             return true;
-           default: /* -1: cmp contains false dependency */
-             *total = 1;
-             return true;
-           }
-       }
+      /* FALLTHRU */
+
+    case CONST_WIDE_INT:
       /* Fall back to (MEM (SYMBOL_REF)), since that's where
         it'll probably end up.  Add a penalty for size.  */
       *total = (COSTS_N_INSNS (1)
-               + (flag_pic != 0 && !TARGET_64BIT)
-               + (mode == SFmode ? 0 : mode == DFmode ? 1 : 2));
+               + (!TARGET_64BIT && flag_pic)
+               + (GET_MODE_SIZE (mode) <= 4
+                  ? 0 : GET_MODE_SIZE (mode) <= 8 ? 1 : 2));
       return true;
 
     case ZERO_EXTEND: