[AArch64] Fix ICE on (const_double:HF 0.0)

gcc/:

	* config/aarch64/aarch64.md (*movhf_aarch64): Use
	aarch64_reg_or_fp_zero for second operand.

gcc/testsuite/:

	* gcc.target/aarch64/fp16/set_zero_1.c: New.

From-SVN: r229701

gcc/ChangeLog

+2015-11-03  Alan Lawrence  <alan.lawrence@arm.com>
+
+	* config/aarch64/aarch64.md (*movhf_aarch64): Use
+	aarch64_reg_or_fp_zero for second operand.
+
 2015-11-03  Alexandre Oliva <aoliva@redhat.com>
 
 	* gimple-expr.c: Include hash-set.h and rtl.h.

gcc/config/aarch64/aarch64.md

@@ -1124,7 +1124,7 @@
   [(set (match_operand:HF 0 "nonimmediate_operand" "=w, ?r,w,w,m,r,m ,r")
 	(match_operand:HF 1 "general_operand"      "?rY, w,w,m,w,m,rY,r"))]
   "TARGET_FLOAT && (register_operand (operands[0], HFmode)
-    || register_operand (operands[1], HFmode))"
+    || aarch64_reg_or_fp_zero (operands[1], HFmode))"
   "@
    mov\\t%0.h[0], %w1
    umov\\t%w0, %1.h[0]

gcc/testsuite/ChangeLog

+2015-11-03  Alan Lawrence  <alan.lawrence@arm.com>
+
+	* gcc.target/aarch64/fp16/set_zero_1.c: New.
+
 2015-11-03  Uros Bizjak  <ubizjak@gmail.com>
 
 	* gcc.dg/mvc1.c: Move to ...

gcc/testsuite/gcc.target/aarch64/fp16/set_zero_1.c

+/* { dg-do run } */
+/* { dg-options "-O2" } */
+/* { dg-additional-options "-mfp16-format=ieee" { target "arm*-*-*" } } */
+
+extern void abort (void);
+
+__attribute__ ((noinline))
+void setfoo (__fp16 *f)
+{
+  *f = 0.0;
+}
+
+int
+main (int argc, char **argv)
+{
+  __fp16 a = 1.0;
+  setfoo (&a);
+  if (a != 0.0)
+    abort ();
+  return 0;
+}