i965/vec4: don't copy propagate vector opcodes that operate in align1 mode

Basically, ALIGN1 mode will ignore swizzles on the input vectors so we don't
want the copy propagation pass to mess with them.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.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 545f4c7..d0045a7 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -283,6 +283,22 @@ try_constant_propagate(const struct gen_device_info *devinfo,
 }
 
 static bool
+is_align1_opcode(unsigned opcode)
+{
+   switch (opcode) {
+   case VEC4_OPCODE_DOUBLE_TO_FLOAT:
+   case VEC4_OPCODE_FLOAT_TO_DOUBLE:
+   case VEC4_OPCODE_PICK_LOW_32BIT:
+   case VEC4_OPCODE_PICK_HIGH_32BIT:
+   case VEC4_OPCODE_SET_LOW_32BIT:
+   case VEC4_OPCODE_SET_HIGH_32BIT:
+      return true;
+   default:
+      return false;
+   }
+}
+
+static bool
 try_copy_propagate(const struct gen_device_info *devinfo,
                    vec4_instruction *inst, int arg,
                    const copy_entry *entry, int attributes_per_reg)
@@ -326,6 +342,14 @@ try_copy_propagate(const struct gen_device_info *devinfo,
 
    unsigned composed_swizzle = brw_compose_swizzle(inst->src[arg].swizzle,
                                                    value.swizzle);
+
+   /* Instructions that operate on vectors in ALIGN1 mode will ignore swizzles
+    * so copy-propagation won't be safe if the composed swizzle is anything
+    * other than the identity.
+    */
+   if (is_align1_opcode(inst->opcode) && composed_swizzle != BRW_SWIZZLE_XYZW)
+      return false;
+
    if (inst->is_3src(devinfo) &&
        (value.file == UNIFORM ||
         (value.file == ATTR && attributes_per_reg != 1)) &&