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Re: Fixes for powerpc-linux param passing
On Sun, May 09, 2004 at 08:49:50AM +0930, Alan Modra wrote:
> Note that this patch just fixes the ABI_V4 case. We have exactly the
> same problem on every other rs6000 ABI in that -mabi=no-altivec doesn't
> align vector params. I'm happy to fix the other ABIs too if everyone
> is agrees. Pass vectors by value in gprs for 64-bit, and by reference
> for 32-bit? Does that sound reasonable?
This changes the remaining -mabi=no-altivec vector passing to 16 byte
alignment. Also removes some useless code as explained by the comments
added to function_arg_advance and function_arg. Regression tested
powerpc-linux and powerpc64-linux.
* config/rs6000/rs6000.c (function_arg_boundary): Always align
AltiVec vectors.
(function_arg_advance): Pass TARGET_32BIT -mabi=no-altivec AltiVec
vectors by refererence. Align the same for TARGET_64BIT to a 16
byte boundary. Remove useless code. Add function comment.
(function_arg): Similarly. Move gpr rs6000_mixed_function_arg
call to where it belongs.
(function_arg_partial_nregs): Return true for all TARGET_32BIT
-mabi=no-altivec AltiVec vectors. Fix debug output.
(rs6000_va_arg): Adjust for AltiVec change.
OK to install?
--- gcc-virgin/gcc/config/rs6000/rs6000.c 2004-05-10 09:06:46.000000000 +0930
+++ gcc-mainline/gcc/config/rs6000/rs6000.c 2004-05-10 18:24:52.000000000 +0930
@@ -4192,7 +4192,7 @@ function_arg_boundary (enum machine_mode
return 64;
else if (SPE_VECTOR_MODE (mode))
return 64;
- else if (TARGET_ALTIVEC_ABI && ALTIVEC_VECTOR_MODE (mode))
+ else if (ALTIVEC_VECTOR_MODE (mode))
return 128;
else
return PARM_BOUNDARY;
@@ -4218,7 +4218,11 @@ rs6000_arg_size (enum machine_mode mode,
/* Update the data in CUM to advance over an argument
of mode MODE and data type TYPE.
- (TYPE is null for libcalls where that information may not be available.) */
+ (TYPE is null for libcalls where that information may not be available.)
+
+ Note that for args passed by reference, function_arg will be called
+ with MODE and TYPE set to that of the pointer to the arg, not the arg
+ itself. */
void
function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode,
@@ -4295,18 +4299,9 @@ function_arg_advance (CUMULATIVE_ARGS *c
}
else
{
- int n_words;
+ int n_words = rs6000_arg_size (mode, type);
int gregno = cum->sysv_gregno;
- /* Aggregates, IEEE quad, and AltiVec vectors get passed by
- reference. */
- if ((type && AGGREGATE_TYPE_P (type))
- || mode == TFmode
- || ALTIVEC_VECTOR_MODE (mode))
- n_words = 1;
- else
- n_words = rs6000_arg_size (mode, type);
-
/* Long long and SPE vectors are put in (r3,r4), (r5,r6),
(r7,r8) or (r9,r10). As does any other 2 word item such
as complex int due to a historical mistake. */
@@ -4342,10 +4337,16 @@ function_arg_advance (CUMULATIVE_ARGS *c
}
else
{
- int align = (TARGET_32BIT && (cum->words & 1) != 0
- && function_arg_boundary (mode, type) == 64) ? 1 : 0;
+ int n_words = rs6000_arg_size (mode, type);
+ int align = function_arg_boundary (mode, type) / PARM_BOUNDARY - 1;
- cum->words += align + rs6000_arg_size (mode, type);
+ /* The simple alignment calculation here works because
+ function_arg_boundary / PARM_BOUNDARY will only be 1 or 2.
+ If we ever want to handle alignments larger than 8 bytes for
+ 32-bit or 16 bytes for 64-bit, then we'll need to take into
+ account the offset to the start of the parm save area. */
+ align &= cum->words;
+ cum->words += align + n_words;
if (GET_MODE_CLASS (mode) == MODE_FLOAT
&& TARGET_HARD_FLOAT && TARGET_FPRS)
@@ -4544,7 +4545,11 @@ rs6000_mixed_function_arg (CUMULATIVE_AR
both an FP and integer register (or possibly FP reg and stack). Library
functions (when CALL_LIBCALL is set) always have the proper types for args,
so we can pass the FP value just in one register. emit_library_function
- doesn't support PARALLEL anyway. */
+ doesn't support PARALLEL anyway.
+
+ Note that for args passed by reference, function_arg will be called
+ with MODE and TYPE set to that of the pointer to the arg, not the arg
+ itself. */
struct rtx_def *
function_arg (CUMULATIVE_ARGS *cum, enum machine_mode mode,
@@ -4658,18 +4663,9 @@ function_arg (CUMULATIVE_ARGS *cum, enum
}
else
{
- int n_words;
+ int n_words = rs6000_arg_size (mode, type);
int gregno = cum->sysv_gregno;
- /* Aggregates, IEEE quad, and AltiVec vectors get passed by
- reference. */
- if ((type && AGGREGATE_TYPE_P (type))
- || mode == TFmode
- || ALTIVEC_VECTOR_MODE (mode))
- n_words = 1;
- else
- n_words = rs6000_arg_size (mode, type);
-
/* Long long and SPE vectors are put in (r3,r4), (r5,r6),
(r7,r8) or (r9,r10). As does any other 2 word item such
as complex int due to a historical mistake. */
@@ -4685,16 +4681,8 @@ function_arg (CUMULATIVE_ARGS *cum, enum
}
else
{
- int align = (TARGET_32BIT && (cum->words & 1) != 0
- && function_arg_boundary (mode, type) == 64) ? 1 : 0;
- int align_words = cum->words + align;
-
- if (type && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
- return NULL_RTX;
-
- if (TARGET_32BIT && TARGET_POWERPC64
- && (mode == DImode || mode == BLKmode))
- return rs6000_mixed_function_arg (cum, mode, type, align_words);
+ int align = function_arg_boundary (mode, type) / PARM_BOUNDARY - 1;
+ int align_words = cum->words + (cum->words & align);
if (USE_FP_FOR_ARG_P (cum, mode, type))
{
@@ -4763,7 +4751,13 @@ function_arg (CUMULATIVE_ARGS *cum, enum
return gen_rtx_PARALLEL (mode, gen_rtvec_v (n, r));
}
else if (align_words < GP_ARG_NUM_REG)
- return gen_rtx_REG (mode, GP_ARG_MIN_REG + align_words);
+ {
+ if (TARGET_32BIT && TARGET_POWERPC64
+ && (mode == DImode || mode == BLKmode))
+ return rs6000_mixed_function_arg (cum, mode, type, align_words);
+
+ return gen_rtx_REG (mode, GP_ARG_MIN_REG + align_words);
+ }
else
return NULL_RTX;
}
@@ -4810,7 +4804,10 @@ function_arg_partial_nregs (CUMULATIVE_A
the argument itself. The pointer is passed in whatever way is
appropriate for passing a pointer to that type.
- Under V.4, structures and unions are passed by reference.
+ Under V.4, aggregates and long double are passed by reference.
+
+ As an extension to all 32-bit ABIs, AltiVec vectors are passed by
+ reference unless the AltiVec vector extension ABI is in force.
As an extension to all ABIs, variable sized types are passed by
reference. */
@@ -4820,17 +4817,18 @@ function_arg_pass_by_reference (CUMULATI
enum machine_mode mode ATTRIBUTE_UNUSED,
tree type, int named ATTRIBUTE_UNUSED)
{
- if (DEFAULT_ABI == ABI_V4
- && ((type && AGGREGATE_TYPE_P (type))
- || mode == TFmode
- || (!TARGET_ALTIVEC_ABI && ALTIVEC_VECTOR_MODE (mode))))
+ if ((DEFAULT_ABI == ABI_V4
+ && ((type && AGGREGATE_TYPE_P (type))
+ || mode == TFmode))
+ || (TARGET_32BIT && !TARGET_ALTIVEC_ABI && ALTIVEC_VECTOR_MODE (mode))
+ || (type && int_size_in_bytes (type) < 0))
{
if (TARGET_DEBUG_ARG)
- fprintf (stderr, "function_arg_pass_by_reference: aggregate\n");
+ fprintf (stderr, "function_arg_pass_by_reference\n");
return 1;
}
- return type && int_size_in_bytes (type) < 0;
+ return 0;
}
static void
@@ -5081,8 +5078,12 @@ rs6000_va_arg (tree valist, tree type)
if (DEFAULT_ABI != ABI_V4)
{
- /* Variable sized types are passed by reference. */
- if (int_size_in_bytes (type) < 0)
+ /* Variable sized types are passed by reference, as are AltiVec
+ vectors when 32-bit and not using the AltiVec ABI extension. */
+ if (int_size_in_bytes (type) < 0
+ || (TARGET_32BIT
+ && !TARGET_ALTIVEC_ABI
+ && ALTIVEC_VECTOR_MODE (TYPE_MODE (type))))
{
u = build_pointer_type (type);
--
Alan Modra
IBM OzLabs - Linux Technology Centre