arm.c (arm_rtx_costs): Improve for xscale multiply.

* config/arm/arm.c (arm_rtx_costs): Improve for xscale multiply.
* testsuite/gcc.dg/arm-g2.c: New test.

From-SVN: r74149

gcc/ChangeLog

+2003-12-01  James Lemke <jim@wasabisystems.com>
+ 
+	* config/arm/arm.c (arm_rtx_costs): Improve for xscale multiply.
+
 2003-12-01  Roger Sayle  <roger@eyesopen.com>
 
 	PR optimization/11634

gcc/config/arm/arm.c

@@ -3389,19 +3389,41 @@ arm_rtx_costs_1 (rtx x, enum rtx_code code, enum rtx_code outer)
 	{
 	  unsigned HOST_WIDE_INT i = (INTVAL (XEXP (x, 1))
 				      & (unsigned HOST_WIDE_INT) 0xffffffff);
-	  int add_cost = const_ok_for_arm (i) ? 4 : 8;
-	  int j;
+	  int cost, const_ok = const_ok_for_arm (i);
+	  int j, booth_unit_size;
+
+	  if (arm_tune_xscale)
+	    {
+	      unsigned HOST_WIDE_INT masked_const;
+
+	      /* The cost will be related to two insns.
+		 First a load of the constant (MOV or LDR), then a multiply. */
+	      cost = 2;
+	      if (! const_ok)
+		cost += 1;      /* LDR is probably more expensive because
+				   of longer result latency. */
+	      masked_const = i & 0xffff8000;
+	      if (masked_const != 0 && masked_const != 0xffff8000)
+		{
+		  masked_const = i & 0xf8000000;
+		  if (masked_const == 0 || masked_const == 0xf8000000)
+		    cost += 1;
+		  else
+		    cost += 2;
+		}
+	      return cost;
+	    }
 	  
 	  /* Tune as appropriate.  */ 
-	  int booth_unit_size = ((tune_flags & FL_FAST_MULT) ? 8 : 2);
-	  
+	  cost = const_ok ? 4 : 8;
+	  booth_unit_size = ((tune_flags & FL_FAST_MULT) ? 8 : 2);
 	  for (j = 0; i && j < 32; j += booth_unit_size)
 	    {
 	      i >>= booth_unit_size;
-	      add_cost += 2;
+	      cost += 2;
 	    }
 
-	  return add_cost;
+	  return cost;
 	}
 
       return (((tune_flags & FL_FAST_MULT) ? 8 : 30)

gcc/testsuite/ChangeLog

+2003-12-01  James Lemke  <jim@wasabisystems.com>
+
+	* gcc.dg/arm-g2.c: New test.
+
 2003-12-01  Roger Sayle  <roger@eyesopen.com>
 
 	PR optimization/11634

gcc/testsuite/gcc.dg/arm-g2.c

+/* Verify that hardware multiply is preferred on XScale. */
+/* { dg-do compile { target xscale*-*-* } } */
+/* { dg-options "-mcpu=xscale -O2" } */
+
+/* Brett Gaines' test case. */
+unsigned BCPL(unsigned) __attribute__ ((naked));
+unsigned BCPL(unsigned seed)
+{
+    /* Best code would be:
+       ldr r1, =2147001325
+       ldr r2, =715136305
+       mla r0, r1, r0, r2
+       mov pc, lr */
+
+    return seed * 2147001325U + 715136305U;
+}
+
+/* We want to suppress running for -mthumb but not for -mthumb-interwork. */
+/* { dg-final { global compiler_flags; if ![string match "*-mthumb *" $compiler_flags] { scan-assembler "mla\[ 	].*" } } } */