[RTL ifcvt] PR rtl-optimization/71594: ICE in noce_emit_cmove due to mismatched source modes

	PR rtl-optimization/71594
	* ifcvt.c (noce_convert_multiple_sets): Wrap new_val or old_val
	into subregs of appropriate mode before trying to emit a conditional
	move.

	* gcc.dg/torture/pr71594.c: New test.

From-SVN: r238013

gcc/ChangeLog

+2016-07-05  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR rtl-optimization/71594
+	* ifcvt.c (noce_convert_multiple_sets): Wrap new_val or old_val
+	into subregs of appropriate mode before trying to emit a conditional
+	move.
+
 2016-07-05  Jan Hubicka  <jh@suse.cz>
 
 	* tree-scalar-evolution.c (iv_can_overflow_p): New function.

gcc/ifcvt.c

@@ -3228,6 +3228,41 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
       if (if_info->then_else_reversed)
 	std::swap (old_val, new_val);
 
+
+      /* We allow simple lowpart register subreg SET sources in
+	 bb_ok_for_noce_convert_multiple_sets.  Be careful when processing
+	 sequences like:
+	 (set (reg:SI r1) (reg:SI r2))
+	 (set (reg:HI r3) (subreg:HI (r1)))
+	 For the second insn new_val or old_val (r1 in this example) will be
+	 taken from the temporaries and have the wider mode which will not
+	 match with the mode of the other source of the conditional move, so
+	 we'll end up trying to emit r4:HI = cond ? (r1:SI) : (r3:HI).
+	 Wrap the two cmove operands into subregs if appropriate to prevent
+	 that.  */
+      if (GET_MODE (new_val) != GET_MODE (temp))
+	{
+	  machine_mode src_mode = GET_MODE (new_val);
+	  machine_mode dst_mode = GET_MODE (temp);
+	  if (GET_MODE_SIZE (src_mode) <= GET_MODE_SIZE (dst_mode))
+	    {
+	      end_sequence ();
+	      return FALSE;
+	    }
+	  new_val = lowpart_subreg (dst_mode, new_val, src_mode);
+	}
+      if (GET_MODE (old_val) != GET_MODE (temp))
+	{
+	  machine_mode src_mode = GET_MODE (old_val);
+	  machine_mode dst_mode = GET_MODE (temp);
+	  if (GET_MODE_SIZE (src_mode) <= GET_MODE_SIZE (dst_mode))
+	    {
+	      end_sequence ();
+	      return FALSE;
+	    }
+	  old_val = lowpart_subreg (dst_mode, old_val, src_mode);
+	}
+
       /* Actually emit the conditional move.  */
       rtx temp_dest = noce_emit_cmove (if_info, temp, cond_code,
 				       x, y, new_val, old_val);

gcc/testsuite/ChangeLog

+2016-07-05  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR rtl-optimization/71594
+	* gcc.dg/torture/pr71594.c: New test.
+
 2016-07-05  Jan Hubicka  <jh@suse.cz>
 
 	* gcc.dg/tree-ssa/scev-14.c: new testcase.

gcc/testsuite/gcc.dg/torture/pr71594.c

+/* { dg-do compile } */
+/* { dg-options "--param max-rtl-if-conversion-insns=2" } */
+
+unsigned short a;
+int b, c;
+int *d;
+void fn1() {
+  *d = 24;
+  for (; *d <= 65;) {
+    unsigned short *e = &a;
+    b = (a &= 0 <= 0) < (c ?: (*e %= *d));
+    for (; *d <= 83;)
+      ;
+  }
+}