re PR target/11598 (testcase gcc.dg/20020118-1.c fails runtime check of…

re PR target/11598 (testcase gcc.dg/20020118-1.c fails runtime check of __attribute__((aligned(16))))

	2003-10-28  Franz Sirl  <Franz.Sirl-kernel@lauterbach.com>

	PR target/11598
	PR libgcj/10610
	* config/rs6000/sysv4.h (PREFERRED_STACK_BOUNDARY): New macro.

From-SVN: r73017

gcc/ChangeLog

+2003-10-28  Franz Sirl  <Franz.Sirl-kernel@lauterbach.com>
+
+	PR target/11598
+	PR libgcj/10610
+	* config/rs6000/sysv4.h (PREFERRED_STACK_BOUNDARY): New macro.
+
 2003-10-28  Richard Earnshaw  <rearnsha@arm.com>
 
 	* arm.c (arm_output_epilogue): When using a frame pointer, don't emit

gcc/config/rs6000/sysv4.h

@@ -389,6 +389,21 @@ do {									\
 #undef	STACK_BOUNDARY
 #define	STACK_BOUNDARY	(TARGET_ALTIVEC_ABI ? 128 : 64)
 
+/* Define this macro if you wish to preserve a certain alignment for
+   the stack pointer, greater than what the hardware enforces.  The
+   definition is a C expression for the desired alignment (measured
+   in bits).  This macro must evaluate to a value equal to or larger
+   than STACK_BOUNDARY.
+   For the SYSV ABI and variants the alignment of the stack pointer
+   is usually controlled manually in rs6000.c. However, to maintain
+   alignment across alloca () in all circumstances,
+   PREFERRED_STACK_BOUNDARY needs to be set as well.
+   This has the additional advantage of allowing a bigger maximum
+   alignment of user objects on the stack.  */
+
+#undef PREFERRED_STACK_BOUNDARY
+#define PREFERRED_STACK_BOUNDARY 128
+
 /* Real stack boundary as mandated by the appropriate ABI.  */
 #define ABI_STACK_BOUNDARY ((TARGET_EABI && !TARGET_ALTIVEC_ABI) ? 64 : 128)