[arm] Further fixes for PR88469

A bitfield that is exactly the same size as an integral type and
naturally aligned will have DECL_BIT_FIELD cleared.  So we need to
check DECL_BIT_FIELD_TYPE to be sure whether or not the underlying
type was declared with a bitfield declaration.

I've also added a test for bitfields that are based on overaligned types.

	PR target/88469
gcc:
	* config/arm/arm.c (arm_needs_double_word_align): Check
	DECL_BIT_FIELD_TYPE.

gcc/testsuite:
	* gcc.target/arm/aapcs/bitfield2.c: New test.
	* gcc.target/arm/aapcs/bitfield3.c: New test.

From-SVN: r268160

gcc/ChangeLog

+2019-01-22  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/88469
+	* config/arm/arm.c (arm_needs_double_word_align): Check
+	DECL_BIT_FIELD_TYPE.
+
 2019-01-22  Hongtao Liu  <hongtao.liu@intel.com>
 	    H.J. Lu  <hongjiu.lu@intel.com>
 

gcc/config/arm/arm.c

@@ -6634,7 +6634,7 @@ arm_needs_doubleword_align (machine_mode mode, const_tree type)
 	  ret = -1;
       }
     else if (TREE_CODE (field) == FIELD_DECL
-	     && DECL_BIT_FIELD (field)
+	     && DECL_BIT_FIELD_TYPE (field)
 	     && TYPE_ALIGN (DECL_BIT_FIELD_TYPE (field)) > PARM_BOUNDARY)
       ret2 = 1;
 

gcc/testsuite/ChangeLog

+2019-01-22  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR target/88469
+	* gcc.target/arm/aapcs/bitfield2.c: New test.
+	* gcc.target/arm/aapcs/bitfield3.c: New test.
+
 2019-01-22  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	PR rtl-optimization/87763

gcc/testsuite/gcc.target/arm/aapcs/bitfield2.c

+/* Test AAPCS layout (alignment).  */
+
+/* { dg-do run { target arm_eabi } } */
+/* { dg-require-effective-target arm32 } */
+/* { dg-options "-O" } */
+
+#ifndef IN_FRAMEWORK
+#define TESTFILE "bitfield2.c"
+
+typedef unsigned int alint __attribute__((aligned (8)));
+
+struct bf
+{
+  alint a: 17;
+  alint b: 15;
+} v = {1, 1};
+
+#include "abitest.h"
+#else
+  ARG (int, 7, R0)
+  ARG (int, 9, R1)
+  ARG (int, 11, R2)
+  /* Alignment of the bitfield type should affect alignment of the overall
+     type, so R3 not used.  */
+  LAST_ARG (struct bf, v, STACK)
+#endif

gcc/testsuite/gcc.target/arm/aapcs/bitfield3.c

+/* Test AAPCS layout (alignment).  */
+
+/* { dg-do run { target arm_eabi } } */
+/* { dg-require-effective-target arm32 } */
+/* { dg-options "-O" } */
+
+#ifndef IN_FRAMEWORK
+#define TESTFILE "bitfield3.c"
+
+struct bf
+{
+  /* Internally this may be mapped to unsigned short.  Ensure we still
+     check the original declaration.  */
+  unsigned long long a: 16;
+  unsigned b: 3;
+} v = {1, 3};
+
+#include "abitest.h"
+#else
+  ARG (int, 7, R0)
+  ARG (int, 9, R1)
+  ARG (int, 11, R2)
+  /* Alignment of the bitfield type should affect alignment of the overall
+     type, so R3 not used.  */
+  LAST_ARG (struct bf, v, STACK)
+#endif