[AArch64/testsuite] Add missing testcase

  Add the missing testcase.
  (forget svn add in previous commit ...)

From-SVN: r218267

gcc/testsuite/gcc.target/aarch64/remat1.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fomit-frame-pointer -fcaller-saves -ffixed-d8 -ffixed-d9 -ffixed-d10 -ffixed-d11 -ffixed-d12 -ffixed-d13 -ffixed-d14 -ffixed-d15" } */
+
+/* Under high register pressure FP immediates should be rematerialized
+   as literal loads rather than being caller-saved to the stack.  */
+
+void
+g (void);
+
+float
+f (float x)
+{
+  x += 3.1f;
+  g ();
+  x *= 3.1f;
+  return x;
+}
+
+/* { dg-final { scan-assembler-times "ldr\ts\[0-9]+, .LC0" 2 } } */
+