Mesa (master): i965: Replace broken handling of dead code with an assert.
Eric Anholt
anholt at kemper.freedesktop.org
Fri Jan 14 21:58:30 UTC 2011
Module: Mesa
Branch: master
Commit: a6e4614ca1284c5731876bb88732b326bf13aba0
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=a6e4614ca1284c5731876bb88732b326bf13aba0
Author: Eric Anholt <eric at anholt.net>
Date: Fri Jan 14 13:17:59 2011 -0800
i965: Replace broken handling of dead code with an assert.
This code should never have been triggered, but I often did anyway
when I disabled optimization passes during debugging, then spent my
time debugging that this code doesn't work.
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 22 ++++++++++++----------
1 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index aa9a80e..a35687d 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -48,6 +48,7 @@ extern "C" {
#include "../glsl/ir_optimization.h"
#include "../glsl/ir_print_visitor.h"
+#define MAX_INSTRUCTION (1 << 30)
static struct brw_reg brw_reg_from_fs_reg(class fs_reg *reg);
struct gl_shader *
@@ -2750,7 +2751,7 @@ fs_visitor::calculate_live_intervals()
return;
for (int i = 0; i < num_vars; i++) {
- def[i] = 1 << 30;
+ def[i] = MAX_INSTRUCTION;
use[i] = -1;
}
@@ -3272,15 +3273,16 @@ 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]);
- }
+ /* We can't handle dead register writes here, without iterating
+ * over the whole instruction stream to find every single dead
+ * write to that register to compare to the live interval of the
+ * other register. Just assert that dead_code_eliminate() has been
+ * called.
+ */
+ assert((this->virtual_grf_use[a] != -1 ||
+ this->virtual_grf_def[a] == MAX_INSTRUCTION) &&
+ (this->virtual_grf_use[b] != -1 ||
+ this->virtual_grf_def[b] == MAX_INSTRUCTION));
return start < end;
}
More information about the mesa-commit
mailing list