re PR middle-end/78468 (libgomp.c/reduction-10.c and many more FAIL)

	PR middle-end/78468
	* emit-rtl.c (init_emit): Add ??? comment for problematic alignment
	settings of the virtual registers.

	Revert again
	2016-08-23  Dominik Vogt  <vogt@linux.vnet.ibm.com>

	* explow.c (get_dynamic_stack_size): Take known alignment of stack
	pointer + STACK_DYNAMIC_OFFSET into account when calculating the size
	needed.

From-SVN: r245124

gcc/ChangeLog

+2017-02-02  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR middle-end/78468
+	* emit-rtl.c (init_emit): Add ??? comment for problematic alignment
+	settings of the virtual registers.
+
+	Revert again
+	2016-08-23  Dominik Vogt  <vogt@linux.vnet.ibm.com>
+
+	* explow.c (get_dynamic_stack_size): Take known alignment of stack
+	pointer + STACK_DYNAMIC_OFFSET into account when calculating the size
+	needed.
+
 2017-02-02  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	* config/s390/vx-builtins.md ("vec_ceil", "vec_floor")

gcc/emit-rtl.c

@@ -5725,10 +5725,13 @@ init_emit (void)
   REGNO_POINTER_ALIGN (HARD_FRAME_POINTER_REGNUM) = STACK_BOUNDARY;
   REGNO_POINTER_ALIGN (ARG_POINTER_REGNUM) = STACK_BOUNDARY;
 
+  /* ??? These are problematic (for example, 3 out of 4 are wrong on
+     32-bit SPARC and cannot be all fixed because of the ABI).  */
   REGNO_POINTER_ALIGN (VIRTUAL_INCOMING_ARGS_REGNUM) = STACK_BOUNDARY;
   REGNO_POINTER_ALIGN (VIRTUAL_STACK_VARS_REGNUM) = STACK_BOUNDARY;
   REGNO_POINTER_ALIGN (VIRTUAL_STACK_DYNAMIC_REGNUM) = STACK_BOUNDARY;
   REGNO_POINTER_ALIGN (VIRTUAL_OUTGOING_ARGS_REGNUM) = STACK_BOUNDARY;
+
   REGNO_POINTER_ALIGN (VIRTUAL_CFA_REGNUM) = BITS_PER_WORD;
 #endif
 

gcc/explow.c

@@ -1233,15 +1233,9 @@ get_dynamic_stack_size (rtx *psize, unsigned size_align,
      example), so we must preventively align the value.  We leave space
      in SIZE for the hole that might result from the alignment operation.  */
 
-  unsigned known_align = REGNO_POINTER_ALIGN (VIRTUAL_STACK_DYNAMIC_REGNUM);
-  if (known_align == 0)
-    known_align = BITS_PER_UNIT;
-  if (required_align > known_align)
-    {
-      extra = (required_align - known_align) / BITS_PER_UNIT;
-      size = plus_constant (Pmode, size, extra);
-      size = force_operand (size, NULL_RTX);
-    }
+  extra = (required_align - BITS_PER_UNIT) / BITS_PER_UNIT;
+  size = plus_constant (Pmode, size, extra);
+  size = force_operand (size, NULL_RTX);
 
   if (flag_stack_usage_info && pstack_usage_size)
     *pstack_usage_size += extra;