Mesa (staging/20.0): intel/fs: Fix unused texture coordinate zeroing on Gen4-5

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Module: Mesa
Branch: staging/20.0
Commit: f27e8fc0b3f5b0becf05991253af0ed131708e5d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f27e8fc0b3f5b0becf05991253af0ed131708e5d

Author: Jason Ekstrand <jason at jlekstrand.net>
Date:   Sun Apr 26 09:48:16 2020 -0500

intel/fs: Fix unused texture coordinate zeroing on Gen4-5

We were inserting the right number of MOVs but, thanks to the way we
advanced msg_end earlier in the function, were often writing the zeros
past the end of where we actually read in the register file.

Cc: mesa-stable at lists.freedesktop.org
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5243>
(cherry picked from commit 94aa7997e45b5314d169bbee5bf22ad368c2fd25)

---

 .pick_status.json             | 2 +-
 src/intel/compiler/brw_fs.cpp | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 86b9c48a6db..ef71127380a 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -337,7 +337,7 @@
         "description": "intel/fs: Fix unused texture coordinate zeroing on Gen4-5",
         "nominated": true,
         "nomination_type": 0,
-        "resolution": 0,
+        "resolution": 1,
         "master_sha": null,
         "because_sha": null
     },
diff --git a/src/intel/compiler/brw_fs.cpp b/src/intel/compiler/brw_fs.cpp
index 6f7f5f02706..3b6ddfa7c4e 100644
--- a/src/intel/compiler/brw_fs.cpp
+++ b/src/intel/compiler/brw_fs.cpp
@@ -4669,7 +4669,8 @@ lower_sampler_logical_send_gen4(const fs_builder &bld, fs_inst *inst, opcode op,
    if (coord_components > 0 &&
        (has_lod || shadow_c.file != BAD_FILE ||
         (op == SHADER_OPCODE_TEX && bld.dispatch_width() == 8))) {
-      for (unsigned i = coord_components; i < 3; i++)
+      assert(coord_components <= 3);
+      for (unsigned i = 0; i < 3 - coord_components; i++)
          bld.MOV(offset(msg_end, bld, i), brw_imm_f(0.0f));
 
       msg_end = offset(msg_end, bld, 3 - coord_components);