[PATCH GCC]Fix test case failure reported in PR54989

[Bin Cheng]

Hi,
The test case "gcc/testsuite/gcc.dg/hoist-register-pressure.c" is failed on
x86_64-apple-darwin because it uses more registers than x86_64-linux. This
can be fixed by simplifying the case using fewer registers. 

Tested on x86_64-apple-darwin/x86_64-linux, is it OK?

Thanks


gcc/testsuite/ChangeLog
2012-10-22  Bin Cheng  <bin.ch...@arm.com>

        * gcc.dg/hoist-register-pressure.c: Simplify the case
        by using fewer registers.



Index: gcc/testsuite/gcc.dg/hoist-register-pressure.c
===================================================================
--- gcc/testsuite/gcc.dg/hoist-register-pressure.c      (revision 192604)
+++ gcc/testsuite/gcc.dg/hoist-register-pressure.c      (working copy)
@@ -13,13 +13,14 @@
      because its rtx_cost is too small.  */
   if (z)
     {
-      a[1] = a[0] + a[2];
-      a[2] = a[1] + a[3];
-      a[3] = a[2] + a[4];
-      a[4] = a[3] + a[5];
-      a[5] = a[4] + a[6];
-      a[6] = a[5] + a[7];
-      a[7] = a[6] + a[8];
+      a[1] = a[0];
+      a[2] = a[1];
+      a[3] = a[3];
+      a[4] = a[5];
+      a[5] = a[7];
+      a[6] = a[11];
+      a[7] = a[13];
+      a[8] = a[17];
       com (x+y);
     }
   else