[AARCH64 PATCH] Don't provide -Wpsabi notes for AARCH64 (PR target/77728)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

As discussed on IRC, apparently the -Wpsabi warning is not appropriate
for aarch64, only for ARM, because only ARM had the almost like new AAPCS,
except for static data members and typedefs (and sometimes
self-inconsistent) ABI, while on AArch64 it only changed in r237224
for GCC 7.

Thus, the following patch reverts the -Wpsabi related changes and keeps just
the ABI fix and some of the cleanups.

Ok for trunk and 7.1 if it passes bootstrap/regtest?  Could somebody from ARM
bootstrap/regtest it?  I can start a distro rpm build with that patch, but
that will likely be slower.

2017-04-26  Jakub Jelinek  <jakub@redhat.com>

	PR target/77728
	* config/aarch64/aarch64.c (struct aarch64_fn_arg_alignment): Remove.
	(aarch64_function_arg_alignment): Return unsigned int again, but still
	ignore TYPE_FIELDS chain decls other than FIELD_DECLs.
	(aarch64_layout_arg): Adjust aarch64_function_arg_alignment caller.
	Don't emit -Wpsabi note.
	(aarch64_function_arg_boundary): Likewise.
	(aarch64_gimplify_va_arg_expr): Adjust aarch64_function_arg_alignment
	caller.
testsuite/
	* g++.dg/abi/pr77728-2.C: Don't expect -Wpsabi notes.

--- gcc/config/aarch64/aarch64.c.jj	2017-04-25 15:55:38.000000000 +0200
+++ gcc/config/aarch64/aarch64.c	2017-04-26 15:59:09.224554190 +0200
@@ -2256,58 +2256,34 @@ aarch64_vfp_is_call_candidate (cumulativ
 						  NULL);
 }
 
-struct aarch64_fn_arg_alignment
-{
-  /* Alignment for FIELD_DECLs in function arguments.  */
-  unsigned int alignment;
-  /* Alignment for decls other than FIELD_DECLs in function arguments.  */
-  unsigned int warn_alignment;
-};
-
-/* Given MODE and TYPE of a function argument, return a pair of alignments in
+/* Given MODE and TYPE of a function argument, return the alignment in
    bits.  The idea is to suppress any stronger alignment requested by
    the user and opt for the natural alignment (specified in AAPCS64 \S 4.1).
    This is a helper function for local use only.  */
 
-static struct aarch64_fn_arg_alignment
+static unsigned int
 aarch64_function_arg_alignment (machine_mode mode, const_tree type)
 {
-  struct aarch64_fn_arg_alignment aa;
-  aa.alignment = 0;
-  aa.warn_alignment = 0;
-
   if (!type)
-    {
-      aa.alignment = GET_MODE_ALIGNMENT (mode);
-      return aa;
-    }
+    return GET_MODE_ALIGNMENT (mode);
 
   if (integer_zerop (TYPE_SIZE (type)))
-    return aa;
+    return 0;
 
   gcc_assert (TYPE_MODE (type) == mode);
 
   if (!AGGREGATE_TYPE_P (type))
-    {
-      aa.alignment = TYPE_ALIGN (TYPE_MAIN_VARIANT (type));
-      return aa;
-    }
+    return TYPE_ALIGN (TYPE_MAIN_VARIANT (type));
 
   if (TREE_CODE (type) == ARRAY_TYPE)
-    {
-      aa.alignment = TYPE_ALIGN (TREE_TYPE (type));
-      return aa;
-    }
+    return TYPE_ALIGN (TREE_TYPE (type));
 
+  unsigned int alignment = 0;
   for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
-    {
-      if (TREE_CODE (field) == FIELD_DECL)
-	aa.alignment = std::max (aa.alignment, DECL_ALIGN (field));
-      else
-	aa.warn_alignment = std::max (aa.warn_alignment, DECL_ALIGN (field));
-    }
+    if (TREE_CODE (field) == FIELD_DECL)
+      alignment = std::max (alignment, DECL_ALIGN (field));
 
-  return aa;
+  return alignment;
 }
 
 /* Layout a function argument according to the AAPCS64 rules.  The rule
@@ -2399,27 +2375,16 @@ aarch64_layout_arg (cumulative_args_t pc
 
       /* C.8 if the argument has an alignment of 16 then the NGRN is
          rounded up to the next even number.  */
-      if (nregs == 2 && ncrn % 2)
-	{
-	  struct aarch64_fn_arg_alignment aa
-	    = aarch64_function_arg_alignment (mode, type);
-
+      if (nregs == 2
+	  && ncrn % 2
 	  /* The == 16 * BITS_PER_UNIT instead of >= 16 * BITS_PER_UNIT
-	     comparisons are there because for > 16 * BITS_PER_UNIT
+	     comparison is there because for > 16 * BITS_PER_UNIT
 	     alignment nregs should be > 2 and therefore it should be
 	     passed by reference rather than value.  */
-	  if (aa.warn_alignment == 16 * BITS_PER_UNIT
-	      && aa.alignment < aa.warn_alignment
-	      && warn_psabi
-	      && currently_expanding_gimple_stmt)
-	    inform (input_location,
-		    "parameter passing for argument of type %qT "
-		    "changed in GCC 7.1", type);
-	  else if (aa.alignment == 16 * BITS_PER_UNIT)
-	    {
-	      ++ncrn;
-	      gcc_assert (ncrn + nregs <= NUM_ARG_REGS);
-	    }
+	  && aarch64_function_arg_alignment (mode, type) == 16 * BITS_PER_UNIT)
+	{
+	  ++ncrn;
+	  gcc_assert (ncrn + nregs <= NUM_ARG_REGS);
 	}
 
       /* NREGS can be 0 when e.g. an empty structure is to be passed.
@@ -2454,10 +2419,8 @@ aarch64_layout_arg (cumulative_args_t pc
      this argument and align the total size if necessary.  */
 on_stack:
   pcum->aapcs_stack_words = size / UNITS_PER_WORD;
-  struct aarch64_fn_arg_alignment aa
-    = aarch64_function_arg_alignment (mode, type);
 
-  if (aa.alignment == 16 * BITS_PER_UNIT)
+  if (aarch64_function_arg_alignment (mode, type) == 16 * BITS_PER_UNIT)
     pcum->aapcs_stack_size = ROUND_UP (pcum->aapcs_stack_size,
 				       16 / UNITS_PER_WORD);
   return;
@@ -2548,17 +2511,8 @@ aarch64_function_arg_regno_p (unsigned r
 static unsigned int
 aarch64_function_arg_boundary (machine_mode mode, const_tree type)
 {
-  struct aarch64_fn_arg_alignment aa
-    = aarch64_function_arg_alignment (mode, type);
-  aa.alignment = MIN (MAX (aa.alignment, PARM_BOUNDARY), STACK_BOUNDARY);
-  aa.warn_alignment
-    = MIN (MAX (aa.warn_alignment, PARM_BOUNDARY), STACK_BOUNDARY);
-
-  if (warn_psabi && aa.warn_alignment > aa.alignment)
-    inform (input_location, "parameter passing for argument of type %qT "
-	    "changed in GCC 7.1", type);
-
-  return aa.alignment;
+  unsigned int alignment = aarch64_function_arg_alignment (mode, type);
+  return MIN (MAX (alignment, PARM_BOUNDARY), STACK_BOUNDARY);
 }
 
 /* For use by FUNCTION_ARG_PADDING (MODE, TYPE).
@@ -10258,9 +10212,7 @@ aarch64_gimplify_va_arg_expr (tree valis
   stack = build3 (COMPONENT_REF, TREE_TYPE (f_stack), unshare_expr (valist),
 		  f_stack, NULL_TREE);
   size = int_size_in_bytes (type);
-  struct aarch64_fn_arg_alignment aa
-    = aarch64_function_arg_alignment (mode, type);
-  align = aa.alignment / BITS_PER_UNIT;
+  align = aarch64_function_arg_alignment (mode, type) / BITS_PER_UNIT;
 
   dw_align = false;
   adjust = 0;
--- gcc/testsuite/g++.dg/abi/pr77728-2.C.jj	2017-04-25 15:55:38.000000000 +0200
+++ gcc/testsuite/g++.dg/abi/pr77728-2.C	2017-04-26 16:01:18.414878207 +0200
@@ -1,5 +1,5 @@
 // { dg-do compile { target { { aarch64-*-* } && c++11 } } }
-// { dg-options "-Wpsabi" }
+// { dg-options "" }
 
 #include <stdarg.h>
 
@@ -30,7 +30,7 @@ struct K : public D { typedef A<N> T; in
 struct L { static int h alignas (16); int i, j, k, l; };
 
 int
-fn1 (int a, B<0> b)	// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" }
+fn1 (int a, B<0> b)
 {
   return a + b.i;
 }
@@ -42,14 +42,13 @@ fn2 (int a, B<1> b)
 }
 
 int
-fn3 (int a, L b)	// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" }
+fn3 (int a, L b)
 {
   return a + b.i;
 }
 
 int
 fn4 (int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k, int l, int m, B<0> n, ...)
-// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
 {
   va_list ap;
   va_start (ap, n);
@@ -110,7 +109,6 @@ fn9 (int a, int b, int c, int d, int e,
 
 int
 fn10 (int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k, int l, int m, J n, ...)
-// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
 {
   va_list ap;
   va_start (ap, n);
@@ -121,7 +119,6 @@ fn10 (int a, int b, int c, int d, int e,
 
 int
 fn11 (int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k, int l, int m, K<0> n, ...)
-// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
 {
   va_list ap;
   va_start (ap, n);
@@ -153,19 +150,16 @@ test ()
   static J j;
   static K<0> k0;
   static K<2> k2;
-  fn1 (1, b0);	// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" }
+  fn1 (1, b0);
   fn2 (1, b1);
-  fn3 (1, l);	// { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" }
+  fn3 (1, l);
   fn4 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, b0, 1, 2, 3, 4);
-  // { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
   fn5 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, b1, 1, 2, 3, 4);
   fn6 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, c, 1, 2, 3, 4);
   fn7 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, e, 1, 2, 3, 4);
   fn8 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, h, 1, 2, 3, 4);
   fn9 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, i, 1, 2, 3, 4);
   fn10 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, j, 1, 2, 3, 4);
-  // { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
   fn11 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, k0, 1, 2, 3, 4);
-  // { dg-message "note: parameter passing for argument of type \[^\n\r]* changed in GCC 7\.1" "" { target *-*-* } .-1 }
   fn12 (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, k2, 1, 2, 3, 4);
 }

	Jakub