From 8e75de31649f877f24f460bc887c827227968403 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Wed, 5 May 2010 09:31:53 -0700
Subject: [PATCH] ir_copy_propagation: Return true if we optimized out any
 assignments.

This may trigger other optimization phases to make more progress themselves.
---
 ir_basic_block.cpp      | 22 ++++++++++++----------
 ir_basic_block.h        |  4 +++-
 ir_copy_propagation.cpp | 15 ++++++++++-----
 3 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/ir_basic_block.cpp b/ir_basic_block.cpp
index b10a25c..455398e 100644
--- a/ir_basic_block.cpp
+++ b/ir_basic_block.cpp
@@ -61,7 +61,9 @@ has_call_callback(ir_instruction *ir, void *data)
  */
 void call_for_basic_blocks(exec_list *instructions,
 			   void (*callback)(ir_instruction *first,
-					    ir_instruction *last))
+					    ir_instruction *last,
+					    void *data),
+			   void *data)
 {
    ir_instruction *leader = NULL;
    ir_instruction *last = NULL;
@@ -76,17 +78,17 @@ void call_for_basic_blocks(exec_list *instructions,
 	 leader = ir;
 
       if ((ir_if = ir->as_if())) {
-	 callback(leader, ir);
+	 callback(leader, ir, data);
 	 leader = NULL;
 
-	 call_for_basic_blocks(&ir_if->then_instructions, callback);
-	 call_for_basic_blocks(&ir_if->else_instructions, callback);
+	 call_for_basic_blocks(&ir_if->then_instructions, callback, data);
+	 call_for_basic_blocks(&ir_if->else_instructions, callback, data);
       } else if ((ir_loop = ir->as_loop())) {
-	 callback(leader, ir);
+	 callback(leader, ir, data);
 	 leader = NULL;
-	 call_for_basic_blocks(&ir_loop->body_instructions, callback);
+	 call_for_basic_blocks(&ir_loop->body_instructions, callback, data);
       } else if (ir->as_return() || ir->as_call()) {
-	 callback(leader, ir);
+	 callback(leader, ir, data);
 	 leader = NULL;
       } else if ((ir_function = ir->as_function())) {
 	 /* A function definition doesn't interrupt our basic block
@@ -103,7 +105,7 @@ void call_for_basic_blocks(exec_list *instructions,
 
 	    ir_sig = (ir_function_signature *)fun_iter.get();
 
-	    call_for_basic_blocks(&ir_sig->body, callback);
+	    call_for_basic_blocks(&ir_sig->body, callback, data);
 	 }
       } else if (ir->as_assignment()) {
 	 bool has_call = false;
@@ -124,13 +126,13 @@ void call_for_basic_blocks(exec_list *instructions,
 	 ir_visit_tree(ir, has_call_callback, &has_call);
 
 	 if (has_call) {
-	    callback(leader, ir);
+	    callback(leader, ir, data);
 	    leader = NULL;
 	 }
       }
       last = ir;
    }
    if (leader) {
-      callback(leader, last);
+      callback(leader, last, data);
    }
 }
diff --git a/ir_basic_block.h b/ir_basic_block.h
index e7993b3..dbd678b 100644
--- a/ir_basic_block.h
+++ b/ir_basic_block.h
@@ -23,4 +23,6 @@
 
 void call_for_basic_blocks(exec_list *instructions,
 			   void (*callback)(ir_instruction *first,
-					    ir_instruction *last));
+					    ir_instruction *last,
+					    void *data),
+			   void *data);
diff --git a/ir_copy_propagation.cpp b/ir_copy_propagation.cpp
index 526ff96..1f8c359 100644
--- a/ir_copy_propagation.cpp
+++ b/ir_copy_propagation.cpp
@@ -216,12 +216,14 @@ ir_copy_propagation_visitor::visit(ir_if *ir)
    ir->condition->accept(this);
 }
 
-static void
+static bool
 propagate_copies(ir_instruction *ir, exec_list *acp)
 {
    ir_copy_propagation_visitor v(acp);
 
    ir->accept(&v);
+
+   return v.progress;
 }
 
 static void
@@ -288,16 +290,19 @@ add_copy(ir_assignment *ir, exec_list *acp)
 
 static void
 copy_propagation_basic_block(ir_instruction *first,
-			     ir_instruction *last)
+			     ir_instruction *last,
+			     void *data)
 {
    ir_instruction *ir;
    /* List of avaialble_copy */
    exec_list acp;
+   bool *out_progress = (bool *)data;
+   bool progress = false;
 
    for (ir = first;; ir = (ir_instruction *)ir->next) {
       ir_assignment *ir_assign = ir->as_assignment();
 
-      propagate_copies(ir, &acp);
+      progress = propagate_copies(ir, &acp) || progress;
 
       if (ir_assign) {
 	 kill_invalidated_copies(ir_assign, &acp);
@@ -307,6 +312,7 @@ copy_propagation_basic_block(ir_instruction *first,
       if (ir == last)
 	 break;
    }
+   *out_progress = progress;
 }
 
 /**
@@ -317,8 +323,7 @@ do_copy_propagation(exec_list *instructions)
 {
    bool progress = false;
 
-   call_for_basic_blocks(instructions, copy_propagation_basic_block);
+   call_for_basic_blocks(instructions, copy_propagation_basic_block, &progress);
 
-   /* FINISHME: Return a legit progress value. */
    return progress;
 }
-- 
2.7.4