X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fglsl%2Floop_controls.cpp;h=79c820436fd6951a0643d9fa1189b83b59136b90;hb=f25d94084ce3225e803c07672c359a4e553b0e08;hp=2eddb91364883745f34ae40b5ae9703edb54270d;hpb=bfe3fbb38e0a3ae7c1efb74282628c2cc5abc3e0;p=mesa.git

diff --git a/src/glsl/loop_controls.cpp b/src/glsl/loop_controls.cpp
index 2eddb913648..79c820436fd 100644
--- a/src/glsl/loop_controls.cpp
+++ b/src/glsl/loop_controls.cpp
@@ -21,7 +21,7 @@
  * DEALINGS IN THE SOFTWARE.
  */
 
-#include <climits>
+#include <limits.h>
 #include "main/compiler.h"
 #include "glsl_types.h"
 #include "loop_analysis.h"
@@ -85,7 +85,10 @@ int
 calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment,
 		     enum ir_expression_operation op)
 {
-   void *mem_ctx = talloc_init(__func__);
+   if (from == NULL || to == NULL || increment == NULL)
+      return -1;
+
+   void *mem_ctx = ralloc_context(NULL);
 
    ir_expression *const sub =
       new(mem_ctx) ir_expression(ir_binop_sub, from->type, to, from);
@@ -144,7 +147,7 @@ calculate_iterations(ir_rvalue *from, ir_rvalue *to, ir_rvalue *increment,
       }
    }
 
-   talloc_free(mem_ctx);
+   ralloc_free(mem_ctx);
    return (valid_loop) ? iter_value : -1;
 }
 
@@ -182,7 +185,14 @@ loop_control_visitor::visit_leave(ir_loop *ir)
     * i is a loop induction variable, c is a constant, and < is any relative
     * operator.
     */
-   int max_iterations = INT_MAX;
+   int max_iterations = ls->max_iterations;
+
+   if(ir->from && ir->to && ir->increment)
+      max_iterations = calculate_iterations(ir->from, ir->to, ir->increment, (ir_expression_operation)ir->cmp);
+
+   if(max_iterations < 0)
+      max_iterations = INT_MAX;
+
    foreach_list(node, &ls->terminators) {
       loop_terminator *t = (loop_terminator *) node;
       ir_if *if_stmt = t->ir;
@@ -204,18 +214,18 @@ loop_control_visitor::visit_leave(ir_loop *ir)
 	  * which.
 	  */
 	 ir_rvalue *counter = cond->operands[0]->as_dereference_variable();
-	 ir_constant *limit = cond->operands[1]->constant_expression_value();
+	 ir_constant *limit = cond->operands[1]->as_constant();
 	 enum ir_expression_operation cmp = cond->operation;
 
 	 if (limit == NULL) {
 	    counter = cond->operands[1]->as_dereference_variable();
-	    limit = cond->operands[0]->constant_expression_value();
+	    limit = cond->operands[0]->as_constant();
 
 	    switch (cmp) {
-	    case ir_binop_less:    cmp = ir_binop_gequal;  break;
-	    case ir_binop_greater: cmp = ir_binop_lequal;  break;
-	    case ir_binop_lequal:  cmp = ir_binop_greater; break;
-	    case ir_binop_gequal:  cmp = ir_binop_less;    break;
+	    case ir_binop_less:    cmp = ir_binop_greater; break;
+	    case ir_binop_greater: cmp = ir_binop_less;    break;
+	    case ir_binop_lequal:  cmp = ir_binop_gequal;  break;
+	    case ir_binop_gequal:  cmp = ir_binop_lequal;  break;
 	    default: assert(!"Should not get here.");
 	    }
 	 }
@@ -234,7 +244,7 @@ loop_control_visitor::visit_leave(ir_loop *ir)
 	       const int iterations = calculate_iterations(init, limit,
 							   lv->increment,
 							   cmp);
-	       if (iterations > 0) {
+	       if (iterations >= 0) {
 		  /* If the new iteration count is lower than the previously
 		   * believed iteration count, update the loop control values.
 		   */
@@ -253,6 +263,10 @@ loop_control_visitor::visit_leave(ir_loop *ir)
 		   * satisfied.
 		   */
 		  if_stmt->remove();
+
+		  assert(ls->num_loop_jumps > 0);
+		  ls->num_loop_jumps--;
+
 		  this->progress = true;
 	       }
 
@@ -267,6 +281,14 @@ loop_control_visitor::visit_leave(ir_loop *ir)
       }
    }
 
+   /* If we have proven the one of the loop exit conditions is satisifed before
+    * running the loop once, remove the loop.
+    */
+   if (max_iterations == 0)
+      ir->remove();
+   else
+      ls->max_iterations = max_iterations;
+
    return visit_continue;
 }