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i965: Be more aggressive in tracking live/dead intervals within loops.

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Fixes glsl-fs-convolution-2, which was blowing up due to the array
access insanity getting at the uniform values within the loop.  Each
temporary was considered live across the whole loop.
This commit is contained in:
Eric Anholt 2010-10-21 16:54:03 -07:00
parent 13cd611f56
commit 1d91f8d916
1 changed files with 41 additions and 13 deletions
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54
src/mesa/drivers/dri/i965/brw_fs.cpp
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@ -2441,6 +2441,7 @@ fs_visitor::calculate_live_intervals()
int *use = talloc_array(mem_ctx, int, num_vars);
int loop_depth = 0;
int loop_start = 0;
int bb_header_ip = 0;
for (int i = 0; i < num_vars; i++) {
def[i] = 1 << 30;
@ -2458,12 +2459,8 @@ fs_visitor::calculate_live_intervals()
loop_depth--;
if (loop_depth == 0) {
/* FINISHME:
*
* Patches up any vars marked for use within the loop as
* live until the end. This is conservative, as there
* will often be variables defined and used inside the
* loop but dead at the end of the loop body.
/* Patches up the use of vars marked for being live across
* the whole loop.
*/
for (int i = 0; i < num_vars; i++) {
if (use[i] == loop_start) {
@ -2472,22 +2469,53 @@ fs_visitor::calculate_live_intervals()
}
}
} else {
int eip = ip;
if (loop_depth)
eip = loop_start;
for (unsigned int i = 0; i < 3; i++) {
if (inst->src[i].file == GRF && inst->src[i].reg != 0) {
use[inst->src[i].reg] = MAX2(use[inst->src[i].reg], eip);
int reg = inst->src[i].reg;
if (!loop_depth || (this->virtual_grf_sizes[reg] == 1 &&
def[reg] >= bb_header_ip)) {
use[reg] = ip;
} else {
def[reg] = MIN2(loop_start, def[reg]);
use[reg] = loop_start;
/* Nobody else is going to go smash our start to
* later in the loop now, because def[reg] now
* points before the bb header.
*/
}
}
}
if (inst->dst.file == GRF && inst->dst.reg != 0) {
def[inst->dst.reg] = MIN2(def[inst->dst.reg], eip);
int reg = inst->dst.reg;
if (!loop_depth || (this->virtual_grf_sizes[reg] == 1 &&
!inst->predicated)) {
def[reg] = MIN2(def[reg], ip);
} else {
def[reg] = MIN2(def[reg], loop_start);
}
}
}
ip++;
/* Set the basic block header IP. This is used for determining
* if a complete def of single-register virtual GRF in a loop
* dominates a use in the same basic block. It's a quick way to
* reduce the live interval range of most register used in a
* loop.
*/
if (inst->opcode == BRW_OPCODE_IF ||
inst->opcode == BRW_OPCODE_ELSE ||
inst->opcode == BRW_OPCODE_ENDIF ||
inst->opcode == BRW_OPCODE_DO ||
inst->opcode == BRW_OPCODE_WHILE ||
inst->opcode == BRW_OPCODE_BREAK ||
inst->opcode == BRW_OPCODE_CONTINUE) {
bb_header_ip = ip;
}
}
talloc_free(this->virtual_grf_def);