Mesa (master): mesa: skip memmove in optimize_state_parameters if it's no-op

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Module: Mesa
Branch: master
Commit: 2a80595ba58c7d1a063973847dc5f2822dc3c406
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=2a80595ba58c7d1a063973847dc5f2822dc3c406

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Fri Dec 11 16:59:00 2020 -0500

mesa: skip memmove in optimize_state_parameters if it's no-op

This doesn't change the behavior. Check if there is at least 1 element
that follows removed parameters.

Reviewed-by: Eric Anholt <eric at anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8183>

---

 src/mesa/program/prog_statevars.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/mesa/program/prog_statevars.c b/src/mesa/program/prog_statevars.c
index 81a821d9972..70c1aab3543 100644
--- a/src/mesa/program/prog_statevars.c
+++ b/src/mesa/program/prog_statevars.c
@@ -1349,10 +1349,12 @@ _mesa_optimize_state_parameters(struct gl_constants *consts,
             free((char*)list->Parameters[i].Name);
 
          /* Remove the merged state vars. */
-         memmove(&list->Parameters[first_param + 1],
-                 &list->Parameters[last_param + 1],
-                 sizeof(list->Parameters[0]) *
-                 (list->NumParameters - last_param - 1));
+         if (last_param + 1 < list->NumParameters) {
+            memmove(&list->Parameters[first_param + 1],
+                    &list->Parameters[last_param + 1],
+                    sizeof(list->Parameters[0]) *
+                    (list->NumParameters - last_param - 1));
+         }
          list->NumParameters -= param_diff;
       }
    }