Mesa (staging/22.1): gallivm: fix ssbo oob reads

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Module: Mesa
Branch: staging/22.1
Commit: 659e41fe794026634d65717a27585e9bbcb4eb91
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=659e41fe794026634d65717a27585e9bbcb4eb91

Author: Mike Blumenkrantz <michael.blumenkrantz at gmail.com>
Date:   Fri Apr 22 13:52:22 2022 -0400

gallivm: fix ssbo oob reads

this was checking (offset < size) when really it needs to be
(offset < size && extent < size && offset >= 0)

Fixes: 591899eedd2 ("gallivm/nir: Add a short circuit uniform-offset mode for load_ssbo/load_shared.")

Reviewed-by: Dave Airlie <airlied at redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16137>
(cherry picked from commit aa98a90265ca9ec844f07b4b2a1d1e07fe33511a)

---

 .pick_status.json                              | 2 +-
 src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/.pick_status.json b/.pick_status.json
index 26f6e1dca0f..ea72a44baab 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -391,7 +391,7 @@
         "description": "gallivm: fix ssbo oob reads",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "591899eedd2d797bfdb7dbb6b3e2169d50d42109"
     },
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
index 5a8fd02561b..fb509bfb685 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
@@ -1181,9 +1181,12 @@ static void emit_load_mem(struct lp_build_nir_context *bld_base,
             LLVMValueRef res_store = lp_build_alloca(gallivm, LLVMTypeOf(zero), "");
             LLVMBuildStore(builder, zero, res_store);
 
-            LLVMValueRef fetch_cond = LLVMBuildICmp(gallivm->builder, LLVMIntUGE, ssbo_limit, chan_offset, "");
+            LLVMValueRef fetch_extent = LLVMBuildAdd(builder, chan_offset, lp_build_const_int32(gallivm, 1), "");
+            LLVMValueRef fetch_cond = LLVMBuildICmp(gallivm->builder, LLVMIntUGE, ssbo_limit, fetch_extent, "");
+            LLVMValueRef fetch_cond2 = LLVMBuildICmp(gallivm->builder, LLVMIntSGE, chan_offset, lp_build_const_int32(gallivm, 0), "");
+            LLVMValueRef fetch_cond_final = LLVMBuildAnd(gallivm->builder, fetch_cond, fetch_cond2, "");
             struct lp_build_if_state ifthen;
-            lp_build_if(&ifthen, gallivm, fetch_cond);
+            lp_build_if(&ifthen, gallivm, fetch_cond_final);
             LLVMBuildStore(builder, lp_build_pointer_get(builder, mem_ptr, chan_offset), res_store);
             lp_build_endif(&ifthen);