Created attachment 115602 [details]
terasology.tgsi
The problem is that the attached shader compiles to:
...
34: mov u32 $r0 $r3 (8)
35: mov u32 $r1 $r5 (8)
36: tex 2D $r0 $s0 f32 $r0t $r0d (8)
37: join mov u32 $r7 $r1 (8)
BB:3 (4 instructions) - idom = BB:0, df = { BB:4 }
-> BB:4 (forward)
38: mov u32 $r0 $r3 (8)
39: mov u32 $r1 $r5 (8)
40: tex 2D $r1 $s0 f32 $r0t $r0d (8)
41: join mov u32 $r7 $r1 (8)
...
And there is no texbar before the mov happens. This causes funky rendering in
Terasology.
Somehow things get merged during RA s.t. the findFirstUses logic decides that
the tex itself is a use (it isn't!) and so it never picks up on the actual use
in that BB (since there's a check to make sure that we only pick the earliest
use in a BB). This much shorter shader reproduces a similar issue as well:
FRAG
DCL IN[0], COLOR, COLOR
DCL OUT[0], COLOR
DCL OUT[1], COLOR[1]
DCL SAMP[0]
DCL SAMP[1]
DCL TEMP[0..4], LOCAL
IMM[0] FLT32 { 0.0010, 1.0000, 0.0000, 2.5000}
5: MOV TEMP[0].xy, IN[0].xyxx
7: FSLT TEMP[2].x, IMM[0].yyyy, IN[0].xxxx
10: UIF TEMP[2].xxxx :0
30: TEX TEMP[1], TEMP[0], SAMP[0], 2D
32: ELSE :0
34: TEX TEMP[1], TEMP[0], SAMP[1], 2D
36: ENDIF
47: UIF TEMP[2].xxxx :0
50: MUL TEMP[1], TEMP[1], IMM[0].xyyy
54: ENDIF
84: MOV TEMP[0].xyz, TEMP[1].xyzx
93: MOV TEMP[1].xyz, TEMP[0].wwww
94: MOV OUT[0], TEMP[0]
95: MOV OUT[1], TEMP[1]
97: END