Julian Brown <jul...@codesourcery.com> writes:
> On Thu, 24 Mar 2011 10:57:06 +0000
> Richard Sandiford <richard.sandif...@linaro.org> wrote:
>
>> Chung-Lin Tang <clt...@codesourcery.com> writes:
>> > PR48183 is a case where ARM NEON instrinsics, under -O -g, produce
>> > debug insns that tries to expand OImode (32-byte integer) zero
>> > constants, much too large to represent as two HOST_WIDE_INTs; as
>> > the internals manual indicates, such large constants are not
>> > supported in general, and ICEs on the GET_MODE_BITSIZE(mode) ==
>> > 2*HOST_BITS_PER_WIDE_INT assertion.
>> >
>> > This patch allows the cases where the large integer constant is
>> > still representable using a single CONST_INT, such as zero(0).
>> > Bootstrapped and tested on i686 and x86_64, cross-tested on ARM,
>> > all without regressions. Okay for trunk?
>> >
>> > Thanks,
>> > Chung-Lin
>> >
>> > 2011-03-20 Chung-Lin Tang <clt...@codesourcery.com>
>> >
>> > * emit-rtl.c (immed_double_const): Allow wider than
>> > 2*HOST_BITS_PER_WIDE_INT mode constants when they are
>> > representable as a single const_int RTX.
>>
>> I realise this might be seen as a good expedient fix, but it makes
>> me a bit uneasy. Not a very constructive rationale, sorry.
>
> FWIW I also had a "fix" for this issue, which is equivalent to
> Chung-Lin's patch apart from only allowing constant-zero (attached).
> That's not really a vote from me for this approach, but maybe limiting
> the extent to which we pretend to support wide-integer constants like
> this is sensible, if we do go that way.
So that each suggestion has a patch, here's mine. I've snipped the
regenerated file from the testcase, but to get a flavour, the changes
are like this:
@@ -6099,63 +6099,72 @@ vtbl1_p8 (poly8x8_t __a, uint8x8_t __b)
__extension__ static __inline int8x8_t __attribute__ ((__always_inline__))
vtbl2_s8 (int8x8x2_t __a, int8x8_t __b)
{
- union { int8x8x2_t __i; __builtin_neon_ti __o; } __au = { __a };
+ union { int8x8x2_t __i; __builtin_neon_ti __o; } __au;
+ __au.__i = __a;
return (int8x8_t)__builtin_neon_vtbl2v8qi (__au.__o, __b);
}
Of course, Chung-Lin's testcase should be included whichever way we go.
Richard
gcc/
* config/arm/neon-gen.ml (params): Separate the union initialisation
from the union itself. Return a list of statements.
(print_variant): Update call accordingly. Add the returned statements
before the ones returned by "return".
* config/arm/arm_neon.h: Regenerate.
Index: gcc/config/arm/neon-gen.ml
===================================================================
--- gcc/config/arm/neon-gen.ml 2009-11-11 15:08:40.000000000 +0000
+++ gcc/config/arm/neon-gen.ml 2011-03-29 11:37:52.000000000 +0100
@@ -165,12 +165,14 @@ let rec element_type ctype =
let params return_by_ptr ps =
let pdecls = ref [] in
+ let pstmts = ref [] in
let ptype t p =
match t with
T_arrayof (num, elts) ->
- let uname = union_string num elts (p ^ "u") in
- let decl = Printf.sprintf "%s = { %s };" uname p in
+ let decl = union_string num elts (p ^ "u") ^ ";" in
+ let assignment = p ^ "u.__i = " ^ p ^ ";" in
pdecls := decl :: !pdecls;
+ pstmts := assignment :: !pstmts;
p ^ "u.__o"
| _ -> add_cast t p in
let plist = match ps with
@@ -183,10 +185,11 @@ let params return_by_ptr ps =
match ps with
Arity0 ret | Arity1 (ret, _) | Arity2 (ret, _, _) | Arity3 (ret, _, _, _)
| Arity4 (ret, _, _, _, _) ->
+ !pdecls, !pstmts,
if return_by_ptr then
- !pdecls, add_cast (T_ptrto (element_type ret)) "&__rv.val[0]" :: plist
+ add_cast (T_ptrto (element_type ret)) "&__rv.val[0]" :: plist
else
- !pdecls, plist
+ plist
let modify_params features plist =
let is_flipped =
@@ -243,14 +246,14 @@ let print_variant opcode features shape
let bits = infoword_value elttype features in
let modesuf = mode_suffix elttype shape in
let return_by_ptr = return_by_ptr features in
- let pdecls, paramlist = params return_by_ptr ctype in
+ let pdecls, pstmts, paramlist = params return_by_ptr ctype in
let paramlist' = modify_params features paramlist in
let paramlist'' = extra_word shape features paramlist' bits in
let parstr = String.concat ", " paramlist'' in
let builtin = Printf.sprintf "__builtin_neon_%s%s (%s)"
(builtin_name features name) modesuf parstr in
- let rdecls, stmts = return ctype return_by_ptr builtin in
- let body = pdecls @ rdecls @ stmts
+ let rdecls, rstmts = return ctype return_by_ptr builtin in
+ let body = pdecls @ rdecls @ pstmts @ rstmts
and fnname = (intrinsic_name name) ^ "_" ^ (string_of_elt elttype) in
print_function ctype fnname body
