ir3/lower_tex_prefetch: Fix crash with lowered load_barycentric_at_offset

ir3_nir_lower_tex_prefetch expects src0 of load_interpolated_input to
be intrinsic, however this assumption broke when src0 is
load_barycentric_at_offset and is lowered in series of alu instructions.

 32x2  %1121 = @load_barycentric_at_offset (%1120) (interp_mode=0)
 32x4  %1118 = @load_interpolated_input (%1121, %1116 (0x0)) ...
 32x2    %32 = vec2 %1118.x, %1118.y
 32x4    %37 = (float32)tex %36 (texture_handle), %34 (sampler_handle), %32 (coord), 0 (texture), 0 (sampler)

is lowered into:

 [...]
 32      %54 = ffma %46.y, %52, %50
 32      %55 = ffma %46.y, %53, %51
 32x2    %56 = vec2 %54, %55
 32x4    %57 = @load_interpolated_input (%56, %25 (0x0))
 [...]

Crash backtrace:

 #5  in __GI___assert_fail (assertion=0x7ff6692328 "parent && parent->type == nir_instr_type_intrinsic",
     file=0x7ff66921c8 "nir.h", line=2536, function=0x7ff6692630 <__PRETTY_FUNCTION__.13> "nir_instr_as_intrinsic")
     at assert.c:101
 #6  in nir_instr_as_intrinsic (parent=0x7fd4b648e8) at nir.h:2536
 #7  in coord_offset (ssa=0x7fd4b649d0) at ir3_nir_lower_tex_prefetch.c:77
 #8  in coord_offset (ssa=0x7fd4b64a90) at ir3_nir_lower_tex_prefetch.c:48
 #9  in ir3_nir_coord_offset (ssa=0x7fd4b64a90) at ir3_nir_lower_tex_prefetch.c:104
 #10 in lower_tex_prefetch_block (block=0x7fd482c100) at ir3_nir_lower_tex_prefetch.c:185
 #11 in lower_tex_prefetch_func (impl=0x7fd4aa0890) at ir3_nir_lower_tex_prefetch.c:218
 #12 in ir3_nir_lower_tex_prefetch (shader=0x7fd4942b10) at ir3_nir_lower_tex_prefetch.c:242

Cc: mesa-stable

Signed-off-by: Danylo Piliaiev <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25096>
(cherry picked from commit b16472f)

Author: werman

.pick_status.json

@@ -841,7 +841,7 @@
         "description": "ir3/lower_tex_prefetch: Fix crash with lowered load_barycentric_at_offset",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null
     },

src/freedreno/ir3/ir3_nir_lower_tex_prefetch.c

@@ -85,6 +85,10 @@ coord_offset(nir_ssa_def *ssa)
    if (!input->src[0].is_ssa)
       return -1;
 
+   /* Happens with lowered load_barycentric_at_offset */
+   if (input->src[0].ssa->parent_instr->type != nir_instr_type_intrinsic)
+      return -1;
+
    nir_intrinsic_instr *interp =
       nir_instr_as_intrinsic(input->src[0].ssa->parent_instr);