On Thu, Jun 13, 2013 at 05:10:51PM +0930, Alan Modra wrote:
> On Wed, Jun 12, 2013 at 12:52:03PM -0500, Edmar Wienskoski wrote:
> > The e500v2 (SPE) hardware is such that if the address of vector (double
> > world
> > load / stores) are not double world aligned the instruction will trap.
> >
> > So this alignment is not optional.
>
> Vector type alignment is also specified by the ppc64 abi. I think we
> want the following. Note that DATA_ALIGNMENT has been broken for
> vectors right from the initial vector support (and the error was
> copied for e500 double). For example
>
> typedef int vec_align __attribute__ ((vector_size(16), aligned(32)));
> vec_align x = { 0, 0, 0, 0 };
>
> currently loses the extra alignment. Fixed by never decreasing
> alignment in DATA_ABI_ALIGNMENT. Testing in progress. OK to
> apply assuming bootstrap is good? (I think I need a change in
> offsettable_ok_by_alignment too. I'll do that in a separate patch.)
Revised patch with offsettable_ok_by_alignment change, avoiding dumb
idea of using statement expressions. This one actually bootstraps and
passes regression testing.
* config/rs6000/rs6000.h (enum data_align): New.
(LOCAL_ALIGNMENT, DATA_ALIGNMENT): Use rs6000_data_alignment.
(DATA_ABI_ALIGNMENT): Define.
(CONSTANT_ALIGNMENT): Correct comment.
* config/rs6000/rs6000-protos.h (rs6000_data_alignment): Declare.
* config/rs6000/rs6000.c (rs6000_data_alignment): New function.
(offsettable_ok_by_alignment): Align by DATA_ABI_ALIGNMENT.
Pass "type" not "decl" to DATA_ALIGNMENT.
Index: gcc/config/rs6000/rs6000.h
===================================================================
--- gcc/config/rs6000/rs6000.h (revision 200055)
+++ gcc/config/rs6000/rs6000.h (working copy)
@@ -813,12 +813,6 @@ extern unsigned rs6000_pointer_size;
/* No data type wants to be aligned rounder than this. */
#define BIGGEST_ALIGNMENT 128
-/* A C expression to compute the alignment for a variables in the
- local store. TYPE is the data type, and ALIGN is the alignment
- that the object would ordinarily have. */
-#define LOCAL_ALIGNMENT(TYPE, ALIGN) \
- DATA_ALIGNMENT (TYPE, ALIGN)
-
/* Alignment of field after `int : 0' in a structure. */
#define EMPTY_FIELD_BOUNDARY 32
@@ -828,8 +822,15 @@ extern unsigned rs6000_pointer_size;
/* A bit-field declared as `int' forces `int' alignment for the struct. */
#define PCC_BITFIELD_TYPE_MATTERS 1
-/* Make strings word-aligned so strcpy from constants will be faster.
- Make vector constants quadword aligned. */
+enum data_align { align_abi, align_opt, align_both };
+
+/* A C expression to compute the alignment for a variables in the
+ local store. TYPE is the data type, and ALIGN is the alignment
+ that the object would ordinarily have. */
+#define LOCAL_ALIGNMENT(TYPE, ALIGN) \
+ rs6000_data_alignment (TYPE, ALIGN, align_both)
+
+/* Make strings word-aligned so strcpy from constants will be faster. */
#define CONSTANT_ALIGNMENT(EXP, ALIGN) \
(TREE_CODE (EXP) == STRING_CST \
&& (STRICT_ALIGNMENT || !optimize_size) \
@@ -837,21 +838,14 @@ extern unsigned rs6000_pointer_size;
? BITS_PER_WORD \
: (ALIGN))
-/* Make arrays of chars word-aligned for the same reasons.
- Align vectors to 128 bits. Align SPE vectors and E500 v2 doubles to
+/* Make arrays of chars word-aligned for the same reasons. */
+#define DATA_ALIGNMENT(TYPE, ALIGN) \
+ rs6000_data_alignment (TYPE, ALIGN, align_opt)
+
+/* Align vectors to 128 bits. Align SPE vectors and E500 v2 doubles to
64 bits. */
-#define DATA_ALIGNMENT(TYPE, ALIGN) \
- (TREE_CODE (TYPE) == VECTOR_TYPE \
- ? (((TARGET_SPE && SPE_VECTOR_MODE (TYPE_MODE (TYPE))) \
- || (TARGET_PAIRED_FLOAT && PAIRED_VECTOR_MODE (TYPE_MODE (TYPE)))) \
- ? 64 : 128) \
- : ((TARGET_E500_DOUBLE \
- && TREE_CODE (TYPE) == REAL_TYPE
\
- && TYPE_MODE (TYPE) == DFmode) \
- ? 64 \
- : (TREE_CODE (TYPE) == ARRAY_TYPE
\
- && TYPE_MODE (TREE_TYPE (TYPE)) == QImode \
- && (ALIGN) < BITS_PER_WORD) ? BITS_PER_WORD : (ALIGN)))
+#define DATA_ABI_ALIGNMENT(TYPE, ALIGN) \
+ rs6000_data_alignment (TYPE, ALIGN, align_abi)
/* Nonzero if move instructions will actually fail to work
when given unaligned data. */
Index: gcc/config/rs6000/rs6000-protos.h
===================================================================
--- gcc/config/rs6000/rs6000-protos.h (revision 200055)
+++ gcc/config/rs6000/rs6000-protos.h (working copy)
@@ -141,6 +141,7 @@ extern int rs6000_loop_align (rtx);
#endif /* RTX_CODE */
#ifdef TREE_CODE
+extern unsigned int rs6000_data_alignment (tree, unsigned int, enum
data_align);
extern unsigned int rs6000_special_round_type_align (tree, unsigned int,
unsigned int);
extern unsigned int darwin_rs6000_special_round_type_align (tree, unsigned int,
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 200055)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -5384,6 +5390,44 @@ invalid_e500_subreg (rtx op, enum machine_mode mod
return false;
}
+/* Return alignment of TYPE. Existing alignment is ALIGN. HOW
+ selects whether the alignment is abi mandated, optional, or
+ both abi and optional alignment. */
+
+unsigned int
+rs6000_data_alignment (tree type, unsigned int align, enum data_align how)
+{
+ if (how != align_opt)
+ {
+ if (TREE_CODE (type) == VECTOR_TYPE)
+ {
+ if ((TARGET_SPE && SPE_VECTOR_MODE (TYPE_MODE (type)))
+ || (TARGET_PAIRED_FLOAT && PAIRED_VECTOR_MODE (TYPE_MODE (type))))
+ {
+ if (align < 64)
+ align = 64;
+ }
+ else if (align < 128)
+ align = 128;
+ }
+ else if (TARGET_E500_DOUBLE
+ && TREE_CODE (type) == REAL_TYPE
+ && TYPE_MODE (type) == DFmode
+ && align < 64)
+ align = 64;
+ }
+
+ if (how != align_abi)
+ {
+ if (TREE_CODE (type) == ARRAY_TYPE
+ && TYPE_MODE (TREE_TYPE (type)) == QImode
+ && align < BITS_PER_WORD)
+ align = BITS_PER_WORD;
+ }
+
+ return align;
+}
+
/* AIX increases natural record alignment to doubleword if the first
field is an FP double while the FP fields remain word aligned. */
@@ -5774,10 +5818,11 @@ offsettable_ok_by_alignment (rtx op, HOST_WIDE_INT
type = TREE_TYPE (decl);
dalign = TYPE_ALIGN (type);
+ dalign = DATA_ABI_ALIGNMENT (type, dalign);
if (CONSTANT_CLASS_P (decl))
dalign = CONSTANT_ALIGNMENT (decl, dalign);
else
- dalign = DATA_ALIGNMENT (decl, dalign);
+ dalign = DATA_ALIGNMENT (type, dalign);
if (dsize == 0)
{
--
Alan Modra
Australia Development Lab, IBM
