Mesa (master): i965: Be more conservative on live interval calculation.
Eric Anholt
anholt at kemper.freedesktop.org
Mon Oct 4 23:09:20 UTC 2010
Module: Mesa
Branch: master
Commit: 9faf64bc32cf7c1a06a302fff9f80d7e2e2685d5
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=9faf64bc32cf7c1a06a302fff9f80d7e2e2685d5
Author: Eric Anholt <eric at anholt.net>
Date: Sun Oct 3 15:01:20 2010 -0700
i965: Be more conservative on live interval calculation.
This also means that our intervals now highlight dead code.
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 14 +++++++++++---
1 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 5ebf906..6106445 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2471,7 +2471,7 @@ fs_visitor::calculate_live_intervals()
for (int i = 0; i < num_vars; i++) {
def[i] = 1 << 30;
- use[i] = 0;
+ use[i] = -1;
}
int ip = 0;
@@ -2506,13 +2506,11 @@ fs_visitor::calculate_live_intervals()
for (unsigned int i = 0; i < 3; i++) {
if (inst->src[i].file == GRF && inst->src[i].reg != 0) {
- def[inst->src[i].reg] = MIN2(def[inst->src[i].reg], eip);
use[inst->src[i].reg] = MAX2(use[inst->src[i].reg], eip);
}
}
if (inst->dst.file == GRF && inst->dst.reg != 0) {
def[inst->dst.reg] = MIN2(def[inst->dst.reg], eip);
- use[inst->dst.reg] = MAX2(use[inst->dst.reg], eip);
}
}
@@ -2529,6 +2527,16 @@ fs_visitor::virtual_grf_interferes(int a, int b)
int start = MAX2(this->virtual_grf_def[a], this->virtual_grf_def[b]);
int end = MIN2(this->virtual_grf_use[a], this->virtual_grf_use[b]);
+ /* For dead code, just check if the def interferes with the other range. */
+ if (this->virtual_grf_use[a] == -1) {
+ return (this->virtual_grf_def[a] >= this->virtual_grf_def[b] &&
+ this->virtual_grf_def[a] < this->virtual_grf_use[b]);
+ }
+ if (this->virtual_grf_use[b] == -1) {
+ return (this->virtual_grf_def[b] >= this->virtual_grf_def[a] &&
+ this->virtual_grf_def[b] < this->virtual_grf_use[a]);
+ }
+
return start <= end;
}
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