re PR rtl-optimization/71984 (wrong code with -O -mavx512cd)

2016-07-26  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/71984
	* simplify-rtx.c (simplify_subreg): Use GET_MODE_SIZE and prepare
	for VOIDmode.

	* gcc.dg/torture/pr71984.c: New testcase.

From-SVN: r238757

gcc/ChangeLog

 2016-07-26  Richard Biener  <rguenther@suse.de>
 
+	PR rtl-optimization/71984
+	* simplify-rtx.c (simplify_subreg): Use GET_MODE_SIZE and prepare
+	for VOIDmode.
+
+2016-07-26  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/72517
 	* expmed.c (extract_bit_field_1): Constrain the vector mode
 	with element size matching the extraction mode size when

gcc/simplify-rtx.c

@@ -6116,7 +6116,10 @@ simplify_subreg (machine_mode outermode, rtx op,
       unsigned int part_size, final_offset;
       rtx part, res;
 
-      part_size = GET_MODE_UNIT_SIZE (GET_MODE (XEXP (op, 0)));
+      enum machine_mode part_mode = GET_MODE (XEXP (op, 0));
+      if (part_mode == VOIDmode)
+	part_mode = GET_MODE_INNER (GET_MODE (op));
+      part_size = GET_MODE_SIZE (part_mode);
       if (byte < part_size)
 	{
 	  part = XEXP (op, 0);
@@ -6131,7 +6134,7 @@ simplify_subreg (machine_mode outermode, rtx op,
       if (final_offset + GET_MODE_SIZE (outermode) > part_size)
 	return NULL_RTX;
 
-      enum machine_mode part_mode = GET_MODE (part);
+      part_mode = GET_MODE (part);
       if (part_mode == VOIDmode)
 	part_mode = GET_MODE_INNER (GET_MODE (op));
       res = simplify_subreg (outermode, part, part_mode, final_offset);

gcc/testsuite/ChangeLog

+2016-07-26  Richard Biener  <rguenther@suse.de>
+
+	PR rtl-optimization/71984
+	* gcc.dg/torture/pr71984.c: New testcase.
+
 2016-07-26  Robert Suchanek  <robert.suchanek@imgtec.com>
 
 	* g++.dg/vect/vect.exp: Add and set new global EFFECTIVE_TARGETS. Call

gcc/testsuite/gcc.dg/torture/pr71984.c

+/* { dg-do run { target lp64 } } */
+/* { dg-additional-options "-w -Wno-psabi" } */
+
+typedef unsigned char v64u8 __attribute__((vector_size(64)));
+typedef unsigned long v64u64 __attribute__((vector_size(64)));
+typedef unsigned char u8;
+
+static u8 __attribute__ ((noinline, noclone))
+foo (v64u64 v64u64_0)
+{
+  return ((v64u8)(v64u64){0, v64u64_0[0]})[13];
+}
+
+int
+main ()
+{
+  u8 x = foo((v64u64){0x0706050403020100UL});
+  if (x != 5)
+    __builtin_abort ();
+  return 0;
+}