i965: Also do constant propagation for the second operand of CMP.

We could do the first operand as well by flipping the comparison, but
this covered several CMPs in code I was looking at.

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 0c9f17f8fdc7a21b9792bf264231213fcf891822..914141a39785a63448360c3a7bab8f20eb7625e9 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2607,6 +2607,11 @@ fs_visitor::propagate_constants()
                  scan_inst->src[1] = inst->src[0];
               }
               break;
+           case BRW_OPCODE_CMP:
+              if (i == 1) {
+                 scan_inst->src[i] = inst->src[0];
+                 progress = true;
+              }
            }
         }