On Thu, 2 Dec 2021 at 23:11, Richard Sandiford
<[email protected]> wrote:
>
> Prathamesh Kulkarni <[email protected]> writes:
> > Hi Richard,
> > I have attached a WIP untested patch for PR96463.
> > IIUC, the PR suggests to transform
> > lhs = svld1rq ({-1, -1, ...}, &v[0])
> > into:
> > lhs = vec_perm_expr<v, v, {0, 0, ...}>
> > if v is vector of 4 elements, and each element is 32 bits on little
> > endian target ?
> >
> > I am sorry if this sounds like a silly question, but I am not sure how
> > to convert a vector of type int32x4_t into svint32_t ? In the patch, I
> > simply used NOP_EXPR (which I expected to fail), and gave type error
> > during gimple verification:
>
> It should be possible in principle to have a VEC_PERM_EXPR in which
> the operands are Advanced SIMD vectors and the result is an SVE vector.
>
> E.g., the dup in the PR would be something like this:
>
> foo (int32x4_t a)
> {
> svint32_t _2;
>
> _2 = VEC_PERM_EXPR <x_1(D), x_1(D), { 0, 1, 2, 3, 0, 1, 2, 3, ... }>;
> return _2;
> }
>
> where the final operand can be built using:
>
> int source_nelts = TYPE_VECTOR_SUBPARTS (…rhs type…).to_constant ();
> vec_perm_builder sel (TYPE_VECTOR_SUBPARTS (…lhs type…), source_nelts, 1);
> for (int i = 0; i < source_nelts; ++i)
> sel.quick_push (i);
>
> I'm not sure how well-tested that combination is though. It might need
> changes to target-independent code.
Hi Richard,
Thanks for the suggestions.
I tried the above approach in attached patch, but it still results in
ICE due to type mismatch:
pr96463.c: In function ‘foo’:
pr96463.c:8:1: error: type mismatch in ‘vec_perm_expr’
8 | }
| ^
svint32_t
int32x4_t
int32x4_t
svint32_t
_3 = VEC_PERM_EXPR <x_4(D), x_4(D), { 0, 1, 2, 3, ... }>;
during GIMPLE pass: ccp
dump file: pr96463.c.032t.ccp1
pr96463.c:8:1: internal compiler error: verify_gimple failed
Should we perhaps add another tree code, that "extends" a fixed-width
vector into it's VLA equivalent ?
Thanks,
Prathamesh
>
> Thanks,
> Richard
diff --git a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
index 02e42a71e5e..b38c4641535 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
@@ -44,6 +44,8 @@
#include "aarch64-sve-builtins-shapes.h"
#include "aarch64-sve-builtins-base.h"
#include "aarch64-sve-builtins-functions.h"
+#include "print-tree.h"
+#include "gimple-pretty-print.h"
using namespace aarch64_sve;
@@ -1207,6 +1209,57 @@ public:
insn_code icode = code_for_aarch64_sve_ld1rq (e.vector_mode (0));
return e.use_contiguous_load_insn (icode);
}
+
+ gimple *
+ fold (gimple_folder &f) const OVERRIDE
+ {
+ tree arg0 = gimple_call_arg (f.call, 0);
+ tree arg1 = gimple_call_arg (f.call, 1);
+
+ /* Transform:
+ lhs = svld1rq ({-1, -1, ... }, &v[0])
+ into:
+ tmp = vec_perm_expr<v, v, {0, 0, ...}>.
+ lhs = nop_expr tmp
+ on little endian target. */
+
+ if (!BYTES_BIG_ENDIAN
+ && integer_all_onesp (arg0)
+ && TREE_CODE (arg1) == ADDR_EXPR)
+ {
+ tree t = TREE_OPERAND (arg1, 0);
+ if (TREE_CODE (t) == ARRAY_REF)
+ {
+ tree index = TREE_OPERAND (t, 1);
+ t = TREE_OPERAND (t, 0);
+ if (integer_zerop (index) && TREE_CODE (t) == VIEW_CONVERT_EXPR)
+ {
+ t = TREE_OPERAND (t, 0);
+ tree vectype = TREE_TYPE (t);
+ if (VECTOR_TYPE_P (vectype)
+ && known_eq (TYPE_VECTOR_SUBPARTS (vectype), 4u)
+ && wi::to_wide (TYPE_SIZE (vectype)) == 128)
+ {
+ tree lhs = gimple_call_lhs (f.call);
+ tree lhs_type = TREE_TYPE (lhs);
+ int source_nelts = TYPE_VECTOR_SUBPARTS
(vectype).to_constant ();
+ vec_perm_builder sel (TYPE_VECTOR_SUBPARTS (lhs_type),
source_nelts, 1);
+ for (int i = 0; i < source_nelts; i++)
+ sel.quick_push (i);
+
+ vec_perm_indices indices (sel, 1, source_nelts);
+ if (!can_vec_perm_const_p (TYPE_MODE (lhs_type), indices))
+ return NULL;
+
+ tree mask = vec_perm_indices_to_tree (lhs_type, indices);
+ return gimple_build_assign (lhs, VEC_PERM_EXPR, t, t, mask);
+ }
+ }
+ }
+ }
+
+ return NULL;
+ }
};
class svld1ro_impl : public load_replicate
