i965/vec4: Fix broken saturate mask check in copy propagation.

try_copy_propagate() was checking the bit of the saturate mask for the
arg-th component of the source to decide whether the whole source
should be saturated (WTF?).  We need to swizzle the original saturate
mask and check that for all enabled channels the saturate flag is
either set or unset, as we cannot saturate a subset of destination
components only.

Reviewed-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 a1050bb1333bc51bc776c5e628d8a009ba774907..73b4f53f04b064aef266a71d17ddc4c05fd48408 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_copy_propagation.cpp
@@ -330,10 +330,17 @@ try_copy_propagate(struct brw_context *brw, vec4_instruction *inst,
    if (value.equals(inst->src[arg]))
       return false;
 
-   /* Limit saturate propagation only to SEL with src1 bounded within 1.0 and 1.0
-    * otherwise, skip copy propagate altogether
-    */
-   if (entry->saturatemask & (1 << arg)) {
+   const unsigned dst_saturate_mask = inst->dst.writemask &
+      brw_apply_swizzle_to_mask(inst->src[arg].swizzle, entry->saturatemask);
+
+   if (dst_saturate_mask) {
+      /* We either saturate all or nothing. */
+      if (dst_saturate_mask != inst->dst.writemask)
+         return false;
+
+      /* Limit saturate propagation only to SEL with src1 bounded within 1.0
+       * and 1.0 otherwise, skip copy propagate altogether
+       */
       switch(inst->opcode) {
       case BRW_OPCODE_SEL:
          if (inst->src[1].file != IMM ||