i965/vec4: skip copy-propate for logical instructions with negated src entries

The negation source modifier on src registers has changed meaning in Broadwell when
used with logical operations. Don't copy propagate when negate src modifier is set
and when the destination instruction is a logical op.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
index 83cf191..3242c3a 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -195,6 +195,15 @@ try_constant_propagation(vec4_instruction *inst, int arg, src_reg *values[4])
    return false;
 }
 
+static bool
+is_logic_op(enum opcode opcode)
+{
+   return (opcode == BRW_OPCODE_AND ||
+           opcode == BRW_OPCODE_OR  ||
+           opcode == BRW_OPCODE_XOR ||
+           opcode == BRW_OPCODE_NOT);
+}
+
 bool
 vec4_visitor::try_copy_propagation(vec4_instruction *inst, int arg,
                                    src_reg *values[4])
@@ -233,6 +242,14 @@ vec4_visitor::try_copy_propagation(vec4_instruction *inst, int arg,
        value.file != ATTR)
       return false;
 
+   if (brw->gen >= 8) {
+      if (value.negate) {
+         if (is_logic_op(inst->opcode)) {
+            return false;
+         }
+      }
+   }
+
    if (inst->src[arg].abs) {
       value.negate = false;
       value.abs = true;