Re: [PATCH][PR tree-optimization/69270] Exploit VRP information in DOM

[Jeff Law]

On 01/14/2016 11:27 AM, Jeff Law wrote:

Apart from what Jakub said we have constant_boolean_node for this,

   true_val = constant_boolean_node (true, TREE_TYPE (op0));
Will update.  Thanks.
Here's the patch which uses constant_boolean_node and verifies the type 
is unsigned when it has a single bit of precision case.

The other part of Jakub's suggestion regresses code generation in the 
final assembly -- we're getting some constant initializations when 
they're not needed.  I'm highly confident we just need to mirror a few 
bits into the uncprop pass, which I'll be looking at directly.

Bootstrapped and regression tested on x86_64.  Installed on the trunk.

Jeff
commit d1bdc38e96ec5ae607a472968134e5d8b0ac4456
Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Fri Jan 15 02:45:44 2016 +0000

           PR tree-optimization/69270
            * tree-ssa-dom.c (ssa_name_has_boolean_range): If the type has a
            single bit of precision, verify it's also unsigned.
            (record_edge_info): Use constant_boolean_node rather than 
fold_convert
            to convert boolean_true/boolean_false to the right type.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@232399 
138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 790662511..6f9c6a5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-01-14  Jeff Law  <l...@redhat.com>
+
+       PR tree-optimization/69270
+       * tree-ssa-dom.c (ssa_name_has_boolean_range): If the type has a
+       single bit of precision, verify it's also unsigned.
+       (record_edge_info): Use constant_boolean_node rather than fold_convert
+       to convert boolean_true/boolean_false to the right type.
+
 2016-01-14  Richard Henderson  <r...@redhat.com>
 
        PR rtl-opt/69014
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index da4faca..f2257b3 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -319,8 +319,8 @@ record_conditions (struct edge_info *edge_info, tree cond, 
tree inverted)
 /* Return TRUE is OP, an SSA_NAME has a range of values [0..1], false
    otherwise.
 
-   This can be because it is a boolean type, any type with
-   a single bit of precision, or has known range of [0..1]
+   This can be because it is a boolean type, any unsigned integral
+   type with a single bit of precision, or has known range of [0..1]
    via VRP analysis.  */
 
 static bool
@@ -332,6 +332,7 @@ ssa_name_has_boolean_range (tree op)
 
   /* An integral type with a single bit of precision.  */
   if (INTEGRAL_TYPE_P (TREE_TYPE (op))
+      && TYPE_UNSIGNED (TREE_TYPE (op))
       && TYPE_PRECISION (TREE_TYPE (op)) == 1)
     return true;
 
@@ -425,10 +426,9 @@ record_edge_info (basic_block bb)
              && ssa_name_has_boolean_range (op0)
               && is_gimple_min_invariant (op1))
             {
-             tree true_val = fold_convert (TREE_TYPE (op0),
-                                           boolean_true_node);
-             tree false_val = fold_convert (TREE_TYPE (op0),
-                                            boolean_false_node);
+             tree true_val = constant_boolean_node (true, TREE_TYPE (op0));
+             tree false_val = constant_boolean_node (false, TREE_TYPE (op0));
+
               if (code == EQ_EXPR)
                 {
                   edge_info = allocate_edge_info (true_edge);