Define ATTRIBUTE_ALIGNED_VALUE to 32 for IA MCU

attribute ((aligned)) should align to the minimum of BIGGEST_ALIGNMENT,
which is 4 bytes for -miamcu.

gcc/

	PR target/66818
	* config/i386/i386.h (ATTRIBUTE_ALIGNED_VALUE): Defined to 32
	for IA MCU.

gcc/testsuite/

	PR target/66818
	* gcc.target/i386/pr66818.c: New test.

From-SVN: r225606

gcc/ChangeLog

 2015-07-09  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR target/66818
+	* config/i386/i386.h (ATTRIBUTE_ALIGNED_VALUE): Defined to 32
+	for IA MCU.
+
+2015-07-09  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR target/66817
 	* config/i386/i386.c (ix86_return_in_memory): Return true
 	if int_size_in_bytes returns negative for IA MCU.

gcc/config/i386/i386.h

@@ -811,7 +811,7 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
 
 /* Alignment value for attribute ((aligned)).  It is a constant since
    it is the part of the ABI.  We shouldn't change it with -mavx.  */
-#define ATTRIBUTE_ALIGNED_VALUE 128
+#define ATTRIBUTE_ALIGNED_VALUE (TARGET_IAMCU ? 32 : 128)
 
 /* Decide whether a variable of mode MODE should be 128 bit aligned.  */
 #define ALIGN_MODE_128(MODE) \

gcc/testsuite/ChangeLog

 2015-07-09  H.J. Lu  <hongjiu.lu@intel.com>
 
+	PR target/66818
+	* gcc.target/i386/pr66818.c: New test.
+
+2015-07-09  H.J. Lu  <hongjiu.lu@intel.com>
+
 	PR target/66817
 	* gcc.target/i386/pr66817.c: New test.
 

gcc/testsuite/gcc.target/i386/pr66818.c

+/* { dg-do compile { target ia32 } } */
+/* { dg-options "-O2 -mno-sse -mno-mmx -miamcu" } */
+
+struct dummy { int x __attribute__((aligned)); };
+int array[__alignof__(struct dummy) == 4 ? 1 : -1];