NeroReflex/mesa
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

r300: properly count maximum used register index

Browse source 
The problem is when we have DP2 or DP3 instruction that writes a w
channel like here:

DP3 temp[148].w, -temp[147].xyz_, temp[57].xyz_;

will get pair-converted to

src0.xyz = temp[147], src1.xyz = temp[57]
DP3, -src0.xyz, src1.xyz
DP3 temp[148].w, -src0._, src0._

where the alpha instruction is a basically just a replicate of the
result from the RGB sub intruction. However the destination register
index in the RBG slot is also 148. Now we pair-schedule and regalloc

src0.xyz = temp[13], src1.xyz = temp[3]
DP3, -src0.xyz, src1.xyz
DP3 temp[3].w, -src0._, src0._

We properly regalloc the alpha channel, but we obviously skip the rgb,
because the writemask is empty there. However when we emit the shader
later, we actually check the number of used regs based on the maximum
used register index and we don't consider the writemasks, so we would
think we use 149 temps. AFAIK the shader would be still completelly OK.
But we would think it hits the HW limits and used a dummy one instead.

Fix this by checking for empty writemasks when marking the registers as
used.

GAINED: shaders/glmark/1-22.shader_test FS

This is also needed to prevent another lost Trine shader from
https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23089

Reviewed-by: Filip Gawin <filip.gawin@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/23838>
This commit is contained in:
Pavel Ondračka 2023-06-23 21:14:43 +02:00 • committed by Marge Bot
parent 561cce32f1
commit 89873e5e5c
1 changed files with 4 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

6
src/gallium/drivers/r300/compiler/r500_fragprog_emit.c
View file

@ -281,8 +281,10 @@ static void emit_paired(struct r300_fragment_program_compiler *c, struct rc_pair
code->inst[ip].inst4 |= R500_ALPHA_ADDRD(inst->Alpha.DestIndex);
code->inst[ip].inst5 |= R500_ALU_RGBA_ADDRD(inst->RGB.DestIndex);
use_temporary(code, inst->Alpha.DestIndex);
use_temporary(code, inst->RGB.DestIndex);
if (inst->Alpha.WriteMask)
use_temporary(code, inst->Alpha.DestIndex);
if (inst->RGB.WriteMask)
use_temporary(code, inst->RGB.DestIndex);
if (inst->RGB.Saturate)
code->inst[ip].inst0 |= R500_INST_RGB_CLAMP;