From: Dave Airlie <airlied@redhat.com>
Date: Wed, 12 Aug 2020 05:48:42 +0000 (+1000)
Subject: llvmpipe: only read 0 for channels being read
X-Git-Url: https://git.libre-soc.org/?p=mesa.git;a=commitdiff_plain;h=430e3310e2aed924dc4e0729644e629007d73ef7

llvmpipe: only read 0 for channels being read

KHR-GL45.robust_buffer_access_behavior.vertex_buffer_objects
on the CTS 4.6.0 branch and this fixes it.

Roland identified that if the vertex format doesn't contain channels
then we shouldn't be overriding them to 0, so RGB fetch out of bounds
should return 0 for RGB, but the A channel should still be getting back
1.

Cc: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6287>
---

diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index 845ed6242b1..22644aa5eab 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -1128,7 +1128,7 @@ fetch_vector(struct gallivm_state *gallivm,
    }
 
    /* out-of-bound fetches return all zeros */
-   for (i = 0; i < TGSI_NUM_CHANNELS; i++) {
+   for (i = 0; i < format_desc->nr_channels; i++) {
       inputs[i] = LLVMBuildBitCast(builder, inputs[i], blduivec.vec_type, "");
       inputs[i] = LLVMBuildAnd(builder, inputs[i], valid_mask, "");
       inputs[i] = LLVMBuildBitCast(builder, inputs[i],