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pan/bi: Rewrite aligned vectors as well 

This still isn't optimal, but it handles another common case where we
have a vector "prefix" and can rewrite directly. The last case is one
where writemasks and such would start coming into play and - for the
moment - is not worth the hike in complexity.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4288>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4288>
This commit is contained in:
Alyssa Rosenzweig 2020-03-23 17:07:27 -04:00 committed by Marge Bot
parent 5a3493c536
commit 6a4fadce12
1 changed files with 63 additions and 16 deletions
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79
src/panfrost/bifrost/bi_lower_combine.c
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@ -108,8 +108,12 @@ bi_rewrite_uses(bi_context *ctx,
* returns false if not (nondestructive in this case). */
static bool
bi_shift_mask_scalar(bi_instruction *ins, signed shift)
bi_shift_mask(bi_instruction *ins, unsigned shift)
{
/* No op and handles the funny cases */
if (!shift)
return true;
unsigned sz = nir_alu_type_get_type_size(ins->dest_type);
unsigned bytes = sz / 8;
@ -124,33 +128,68 @@ bi_shift_mask_scalar(bi_instruction *ins, signed shift)
return false;
}
/* Shift swizzle so old i'th component is accessed by new (i + j)'th
* component where j is component shift */
unsigned component_shift = shift / bytes;
/* Sanity check to avoid memory corruption */
if (component_shift >= sizeof(ins->swizzle[0]))
return false;
/* Otherwise, shift is divisible by bytes, and all relevant src types
* are the same size as the dest type. */
ins->writemask <<= shift;
/* Shift swizzle so old i'th component is accessed by new (i + j)'th
* component where j is component shift */
signed component_shift = shift / bytes;
bi_foreach_src(ins, s) {
if (!ins->src[s]) continue;
size_t overlap = sizeof(ins->swizzle[s]) - abs(component_shift);
if (component_shift > 0)
memmove(ins->swizzle[s] + component_shift, ins->swizzle[s], overlap);
else
memmove(ins->swizzle[s], ins->swizzle[s] - component_shift, overlap);
size_t overlap = sizeof(ins->swizzle[s]) - component_shift;
memmove(ins->swizzle[s] + component_shift, ins->swizzle[s], overlap);
}
return true;
}
/* Checks if we have a nicely aligned vector prefix */
static bool
bi_is_aligned_vec(bi_instruction *combine, unsigned s, bi_instruction *parent,
unsigned *count)
{
/* We only support prefixes */
if (s != 0)
return false;
/* Is it a contiguous write? */
unsigned writes = util_bitcount(parent->writemask);
if (parent->writemask != ((1 << writes) - 1))
return false;
/* Okay - how many components? */
unsigned bytes = nir_alu_type_get_type_size(parent->dest_type) / 8;
unsigned components = writes / bytes;
/* Are we contiguous like that? */
for (unsigned i = 0; i < components; ++i) {
if (combine->src[i] != parent->dest)
return false;
if (combine->swizzle[i][0] != i)
return false;
}
/* We're good to go */
*count = components;
return true;
}
/* Tries to lower a given source of a combine to an appropriate rewrite,
* returning true if successful, and false with no changes otherwise. */
static bool
bi_lower_combine_src(bi_context *ctx, bi_instruction *ins, unsigned s, unsigned R)
bi_lower_combine_src(bi_context *ctx, bi_instruction *ins, unsigned s, unsigned R,
unsigned *vec_count)
{
unsigned src = ins->src[s];
@ -171,9 +210,10 @@ bi_lower_combine_src(bi_context *ctx, bi_instruction *ins, unsigned s, unsigned
unsigned pbytes = nir_alu_type_get_type_size(parent->dest_type) / 8;
if (pbytes != bytes) return false;
/* Scalar? */
if (parent->writemask != ((1 << bytes) - 1)) return false;
if (!bi_shift_mask_scalar(parent, bytes * s)) return false;
bool scalar = (parent->writemask == ((1 << bytes) - 1));
if (!(scalar || bi_is_aligned_vec(ins, s, parent, vec_count))) return false;
if (!bi_shift_mask(parent, bytes * s)) return false;
bi_rewrite_uses(ctx, parent->dest, 0, R, s);
parent->dest = R;
return true;
@ -191,8 +231,15 @@ bi_lower_combine(bi_context *ctx, bi_block *block)
unsigned R = bi_make_temp_reg(ctx);
bi_foreach_src(ins, s) {
if (!bi_lower_combine_src(ctx, ins, s, R))
unsigned vec_count = 0;
if (bi_lower_combine_src(ctx, ins, s, R, &vec_count)) {
/* Skip vectored sources */
if (vec_count)
s += (vec_count - 1);
} else {
bi_insert_combine_mov(ctx, ins, s, R);
}
}