glsl: Improve debug output and variable names for opt_dead_code_local.

I know this code has confused others, and it confused me 3 years later,
too.

Reviewed-by: Topi Pohjolainen <topi.pohjolainen@intel.com>

diff --git a/src/glsl/opt_dead_code_local.cpp b/src/glsl/opt_dead_code_local.cpp
index e7d46edbe3e9c68e8320b223a6242687a43c6437..0c5c684a4a9413ae7557df59187ac0cee43139ea 100644 (file)
--- a/src/glsl/opt_dead_code_local.cpp
+++ b/src/glsl/opt_dead_code_local.cpp
@@ -51,14 +51,14 @@ public:
       assert(ir);
       this->lhs = lhs;
       this->ir = ir;
-      this->available = ir->write_mask;
+      this->unused = ir->write_mask;
    }
 
    ir_variable *lhs;
    ir_assignment *ir;
 
    /* bitmask of xyzw channels written that haven't been used so far. */
-   int available;
+   int unused;
 };
 
 class kill_for_derefs_visitor : public ir_hierarchical_visitor {
@@ -68,7 +68,7 @@ public:
       this->assignments = assignments;
    }
 
-   void kill_channels(ir_variable *const var, int used)
+   void use_channels(ir_variable *const var, int used)
    {
       foreach_list_safe(n, this->assignments) {
         assignment_entry *entry = (assignment_entry *) n;
@@ -76,14 +76,14 @@ public:
         if (entry->lhs == var) {
            if (var->type->is_scalar() || var->type->is_vector()) {
               if (debug)
-                 printf("kill %s (0x%01x - 0x%01x)\n", entry->lhs->name,
-                        entry->available, used);
-              entry->available &= ~used;
-              if (!entry->available)
+                 printf("used %s (0x%01x - 0x%01x)\n", entry->lhs->name,
+                        entry->unused, used & 0xf);
+              entry->unused &= ~used;
+              if (!entry->unused)
                  entry->remove();
            } else {
               if (debug)
-                 printf("kill %s\n", entry->lhs->name);
+                 printf("used %s\n", entry->lhs->name);
               entry->remove();
            }
         }
@@ -92,7 +92,7 @@ public:
 
    virtual ir_visitor_status visit(ir_dereference_variable *ir)
    {
-      kill_channels(ir->var, ~0);
+      use_channels(ir->var, ~0);
 
       return visit_continue;
    }
@@ -109,7 +109,7 @@ public:
       used |= 1 << ir->mask.z;
       used |= 1 << ir->mask.w;
 
-      kill_channels(deref->var, used);
+      use_channels(deref->var, used);
 
       return visit_continue_with_parent;
    }
@@ -202,7 +202,7 @@ process_assignment(void *ctx, ir_assignment *ir, exec_list *assignments)
            if (entry->lhs != var)
               continue;
 
-           int remove = entry->available & ir->write_mask;
+           int remove = entry->unused & ir->write_mask;
            if (debug) {
               printf("%s 0x%01x - 0x%01x = 0x%01x\n",
                      var->name,
@@ -219,7 +219,7 @@ process_assignment(void *ctx, ir_assignment *ir, exec_list *assignments)
               }
 
               entry->ir->write_mask &= ~remove;
-              entry->available &= ~remove;
+              entry->unused &= ~remove;
               if (entry->ir->write_mask == 0) {
                  /* Delete the dead assignment. */
                  entry->ir->remove();
@@ -283,7 +283,7 @@ process_assignment(void *ctx, ir_assignment *ir, exec_list *assignments)
       foreach_list(n, assignments) {
         assignment_entry *entry = (assignment_entry *) n;
 
-        printf("    %s (0x%01x)\n", entry->lhs->name, entry->available);
+        printf("    %s (0x%01x)\n", entry->lhs->name, entry->unused);
       }
    }