Mesa (master): i965/fs: skip copy-propate for logical instructions with negated src entries

[Matt Turner]

Module: Mesa
Branch: master
Commit: 609d00e13e1e3e61ce540c42250c35977d4bcaa1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=609d00e13e1e3e61ce540c42250c35977d4bcaa1

Author: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
Date:   Thu Jun  5 11:05:29 2014 -0700

i965/fs: 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 at gmail.com>
Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>

---

 src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
index d3d59aa..158d0ba 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
@@ -272,6 +272,15 @@ fs_copy_prop_dataflow::dump_block_data() const
    }
 }
 
+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
 fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
 {
@@ -330,6 +339,14 @@ fs_visitor::try_copy_propagate(fs_inst *inst, int arg, acp_entry *entry)
    if (has_source_modifiers && entry->dst.type != inst->src[arg].type)
       return false;
 
+   if (brw->gen >= 8) {
+      if (entry->src.negate) {
+         if (is_logic_op(inst->opcode)) {
+            return false;
+         }
+      }
+   }
+
    inst->src[arg].file = entry->src.file;
    inst->src[arg].reg = entry->src.reg;
    inst->src[arg].reg_offset = entry->src.reg_offset;