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broadcom/compiler: allow ldunifa with indirect uniform loads

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We handle uniforms by copying them into the uniform stream to be
consumed with ldunif when they have a constant offset. Otherwise
we fallback to general TMU access, which has more latency.

However, just like we did for UBOs and read-only SSBOs, we can
also try to use the unifa mechanism to handle indirect accesses
in certain cases instead of the TMU fallback.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15575>
This commit is contained in:
Iago Toral Quiroga
2022-03-24 10:45:50 +01:00
committed by Marge Bot
parent ea3223e7a4
commit ce849032a4
1 changed files with 41 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/broadcom/compiler/nir_to_vir.c
+41 -15
View File
@@ -2638,6 +2638,9 @@ vir_emit_tlb_color_read(struct v3d_compile *c, nir_intrinsic_instr *instr)
vir_MOV(c, color_reads_for_sample[component]));
}
static bool
ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr);
static bool
try_emit_uniform(struct v3d_compile *c,
int offset,
@@ -2690,7 +2693,10 @@ ntq_emit_load_uniform(struct v3d_compile *c, nir_intrinsic_instr *instr)
}
}
ntq_emit_tmu_general(c, instr, false);
if (!ntq_emit_load_unifa(c, instr)) {
ntq_emit_tmu_general(c, instr, false);
c->has_general_tmu_load = true;
}
}
static bool
@@ -3052,7 +3058,12 @@ static bool
ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
{
assert(instr->intrinsic == nir_intrinsic_load_ubo ||
instr->intrinsic == nir_intrinsic_load_ssbo);
instr->intrinsic == nir_intrinsic_load_ssbo ||
instr->intrinsic == nir_intrinsic_load_uniform);
bool is_uniform = instr->intrinsic == nir_intrinsic_load_uniform;
bool is_ubo = instr->intrinsic == nir_intrinsic_load_ubo;
bool is_ssbo = instr->intrinsic == nir_intrinsic_load_ssbo;
/* Every ldunifa auto-increments the unifa address by 4 bytes, so our
* current unifa offset is 4 bytes ahead of the offset of the last load.
@@ -3061,14 +3072,28 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
MAX_UNIFA_SKIP_DISTANCE - 4;
/* We can only use unifa if the offset is uniform */
if (nir_src_is_divergent(instr->src[1]))
nir_src offset = is_uniform ? instr->src[0] : instr->src[1];
if (nir_src_is_divergent(offset))
return false;
/* We can only use unifa with SSBOs if they are read-only */
bool is_ubo = instr->intrinsic == nir_intrinsic_load_ubo;
if (!is_ubo && !(nir_intrinsic_access(instr) & ACCESS_NON_WRITEABLE))
/* We can only use unifa with SSBOs if they are read-only. Otherwise
* ldunifa won't see the shader writes to that address (possibly
* because ldunifa doesn't read from the L2T cache).
*/
if (is_ssbo && !(nir_intrinsic_access(instr) & ACCESS_NON_WRITEABLE))
return false;
/* Just as with SSBOs, we can't use ldunifa to read indirect uniforms
* that we may have been written to scratch using the TMU.
*/
bool dynamic_src = !nir_src_is_const(offset);
if (is_uniform && dynamic_src && c->s->scratch_size > 0)
return false;
uint32_t const_offset = dynamic_src ? 0 : nir_src_as_uint(offset);
if (is_uniform)
const_offset += nir_intrinsic_base(instr);
/* ldunifa is a 32-bit load instruction so we can only use it with
* 32-bit aligned addresses. We always produce 32-bit aligned addresses
* except for types smaller than 32-bit, so in these cases we can only
@@ -3076,9 +3101,6 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
* loads with a constant offset.
*/
uint32_t bit_size = nir_dest_bit_size(instr->dest);
bool dynamic_src = !nir_src_is_const(instr->src[1]);
uint32_t const_offset =
dynamic_src ? 0 : nir_src_as_uint(instr->src[1]);
uint32_t value_skips = 0;
if (bit_size < 32) {
if (dynamic_src) {
@@ -3096,10 +3118,14 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
(bit_size == 16 && value_skips <= 1) ||
(bit_size == 8 && value_skips <= 3));
/* Both Vulkan and OpenGL reserve index 0 for uniforms / push
* constants.
*/
uint32_t index = is_uniform ? 0 : nir_src_as_uint(instr->src[0]);
/* On OpenGL QUNIFORM_UBO_ADDR takes a UBO index
* shifted up by 1 (0 is gallium's constant buffer 0).
*/
uint32_t index = nir_src_as_uint(instr->src[0]);
if (is_ubo && c->key->environment == V3D_ENVIRONMENT_OPENGL)
index++;
@@ -3114,7 +3140,7 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
if (dynamic_src) {
c->current_unifa_block = NULL;
} else if (c->cur_block == c->current_unifa_block &&
c->current_unifa_is_ubo == is_ubo &&
c->current_unifa_is_ubo == !is_ssbo &&
c->current_unifa_index == index &&
c->current_unifa_offset <= const_offset &&
c->current_unifa_offset + max_unifa_skip_dist >= const_offset) {
@@ -3122,20 +3148,20 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
ldunifa_skips = (const_offset - c->current_unifa_offset) / 4;
} else {
c->current_unifa_block = c->cur_block;
c->current_unifa_is_ubo = is_ubo;
c->current_unifa_is_ubo = !is_ssbo;
c->current_unifa_index = index;
c->current_unifa_offset = const_offset;
}
if (!skip_unifa) {
struct qreg base_offset = is_ubo ?
struct qreg base_offset = !is_ssbo ?
vir_uniform(c, QUNIFORM_UBO_ADDR,
v3d_unit_data_create(index, const_offset)) :
vir_uniform(c, QUNIFORM_SSBO_OFFSET, index);
struct qreg unifa = vir_reg(QFILE_MAGIC, V3D_QPU_WADDR_UNIFA);
if (!dynamic_src) {
if (is_ubo) {
if (!is_ssbo) {
vir_MOV_dest(c, unifa, base_offset);
} else {
vir_ADD_dest(c, unifa, base_offset,
@@ -3143,7 +3169,7 @@ ntq_emit_load_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr)
}
} else {
vir_ADD_dest(c, unifa, base_offset,
ntq_get_src(c, instr->src[1], 0));
ntq_get_src(c, offset, 0));
}
} else {
for (int i = 0; i < ldunifa_skips; i++)