[simplify-rtx] Zero-initialise local array in simplify_immed_subreg

	* simplify-rtx.c (simplify_immed_subreg): Zero-initialize tmp array
	before merging in bytes to pass down to real_from_target.

From-SVN: r240866

gcc/ChangeLog

+2016-10-07  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* simplify-rtx.c (simplify_immed_subreg): Zero-initialize tmp array
+	before merging in bytes to pass down to real_from_target.
+
 2016-10-07  Richard Biener  <rguenther@suse.de>
 
 	* tree-ssa-propagate.c (replace_phi_args_in): Remove no longer

gcc/simplify-rtx.c

@@ -5893,14 +5893,12 @@ simplify_immed_subreg (machine_mode outermode, rtx op,
 	case MODE_DECIMAL_FLOAT:
 	  {
 	    REAL_VALUE_TYPE r;
-	    long tmp[MAX_BITSIZE_MODE_ANY_MODE / 32];
+	    long tmp[MAX_BITSIZE_MODE_ANY_MODE / 32] = { 0 };
 
 	    /* real_from_target wants its input in words affected by
 	       FLOAT_WORDS_BIG_ENDIAN.  However, we ignore this,
 	       and use WORDS_BIG_ENDIAN instead; see the documentation
 	       of SUBREG in rtl.texi.  */
-	    for (i = 0; i < max_bitsize / 32; i++)
-	      tmp[i] = 0;
 	    for (i = 0; i < elem_bitsize; i += value_bit)
 	      {
 		int ibase;