tgsi: Determine which shader input channels are effectively.

TGSI's UsageMask flag is never set. We can move this logic into
tgsi_ureg, but there there are still cases where's not used, so this
seems a better place for now.

1 files changed, 25 insertions, 7 deletions

diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.c b/src/gallium/auxiliary/tgsi/tgsi_scan.c
index e0c5d3d3d6..7ee272b949 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_scan.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_scan.c
@@ -36,6 +36,7 @@
 
 #include "util/u_math.h"
 #include "tgsi/tgsi_parse.h"
+#include "tgsi/tgsi_util.h"
 #include "tgsi/tgsi_scan.h"
 
 
@@ -84,19 +85,21 @@ tgsi_scan_shader(const struct tgsi_token *tokens,
          {
             const struct tgsi_full_instruction *fullinst
                = &parse.FullToken.FullInstruction;
+            uint i;
 
             assert(fullinst->Instruction.Opcode < TGSI_OPCODE_LAST);
             info->opcode_count[fullinst->Instruction.Opcode]++;
 
-            /* check if we read the frag shader FOG or FACE inputs */
-            if (procType == TGSI_PROCESSOR_FRAGMENT) {
-               uint i;
-               for (i = 0; i < fullinst->Instruction.NumSrcRegs; i++) {
-                  const struct tgsi_full_src_register *src =
-                     &fullinst->Src[i];
+            for (i = 0; i < fullinst->Instruction.NumSrcRegs; i++) {
+               const struct tgsi_full_src_register *src =
+                  &fullinst->Src[i];
+               int ind = src->Register.Index;
+
+               /* check if we read the frag shader FOG or FACE inputs */
+               if (procType == TGSI_PROCESSOR_FRAGMENT) {
                   if (src->Register.File == TGSI_FILE_INPUT ||
                       src->Register.File == TGSI_FILE_SYSTEM_VALUE) {
-                     const int ind = src->Register.Index;
+                     assert(ind >= 0);
                      if (info->input_semantic_name[ind] == TGSI_SEMANTIC_FOG) {
                         info->uses_fogcoord = TRUE;
                      }
@@ -105,6 +108,21 @@ tgsi_scan_shader(const struct tgsi_token *tokens,
                      }
                   }
                }
+
+               /* Mark which inputs are effectively used */
+               if (src->Register.File == TGSI_FILE_INPUT) {
+                  unsigned usage_mask;
+                  usage_mask = tgsi_util_get_inst_usage_mask(fullinst, i);
+                  if (src->Register.Indirect) {
+                     for (ind = 0; ind < info->num_inputs; ++ind) {
+                        info->input_usage_mask[ind] |= usage_mask;
+                     }
+                  } else {
+                     assert(ind >= 0);
+                     assert(ind < PIPE_MAX_SHADER_INPUTS);
+                     info->input_usage_mask[ind] |= usage_mask;
+                  }
+               }
             }
 
             info->num_instructions++;