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i965/vs: Use a fixed set of register classes.

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Arrays, structures, and matrices use large VGRFs of arbitrary sizes.
However, split_virtual_grfs() breaks those down into VGRFs of size 1.

For reference, commit 5d90b98879 is the
analogous change to the FS backend.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
This commit is contained in:
Kenneth Graunke
2013-08-21 16:01:45 -07:00
parent cfe39ea14e
commit 528d70d0b5
1 changed files with 13 additions and 37 deletions
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src/mesa/drivers/dri/i965/brw_vec4_reg_allocate.cpp
+13 -37
View File
@@ -97,11 +97,15 @@ vec4_visitor::reg_allocate_trivial()
}
static void
brw_alloc_reg_set_for_classes(struct brw_context *brw,
int *class_sizes,
int class_count,
int base_reg_count)
brw_alloc_reg_set(struct brw_context *brw, int base_reg_count)
{
/* After running split_virtual_grfs(), almost all VGRFs will be of size 1.
* SEND-from-GRF sources cannot be split, so we also need classes for each
* potential message length.
*/
const int class_count = 2;
const int class_sizes[class_count] = {1, 2};
/* Compute the total number of registers across all classes. */
int ra_reg_count = 0;
for (int i = 0; i < class_count; i++) {
@@ -150,8 +154,6 @@ vec4_visitor::reg_allocate()
unsigned int hw_reg_mapping[virtual_grf_count];
int first_assigned_grf = this->first_non_payload_grf;
int base_reg_count = max_grf - first_assigned_grf;
int class_sizes[base_reg_count];
int class_count = 0;
/* Using the trivial allocator can be useful in debugging undefined
* register access as a result of broken optimization passes.
@@ -161,42 +163,16 @@ vec4_visitor::reg_allocate()
calculate_live_intervals();
/* Set up the register classes.
*
* The base registers store a vec4. However, we'll need larger
* storage for arrays, structures, and matrices, which will be sets
* of contiguous registers.
*/
class_sizes[class_count++] = 1;
for (int r = 0; r < virtual_grf_count; r++) {
int i;
for (i = 0; i < class_count; i++) {
if (class_sizes[i] == this->virtual_grf_sizes[r])
break;
}
if (i == class_count) {
if (this->virtual_grf_sizes[r] >= base_reg_count) {
fail("Object too large to register allocate.\n");
}
class_sizes[class_count++] = this->virtual_grf_sizes[r];
}
}
brw_alloc_reg_set_for_classes(brw, class_sizes, class_count, base_reg_count);
brw_alloc_reg_set(brw, base_reg_count);
struct ra_graph *g = ra_alloc_interference_graph(brw->vs.regs,
virtual_grf_count);
for (int i = 0; i < virtual_grf_count; i++) {
for (int c = 0; c < class_count; c++) {
if (class_sizes[c] == this->virtual_grf_sizes[i]) {
ra_set_node_class(g, i, brw->vs.classes[c]);
break;
}
}
int size = this->virtual_grf_sizes[i];
assert(size >= 1 && size <= 2 &&
"Register allocation relies on split_virtual_grfs().");
ra_set_node_class(g, i, brw->vs.classes[size - 1]);
for (int j = 0; j < i; j++) {
if (virtual_grf_interferes(i, j)) {