re PR tree-optimization/21563 (A trivial VRP opportunity missed)

gcc/
	PR tree-optimization/21563
	* tree-vrp.c (compare_value): Return boolean_false_node when
	SSA_NAME in "if (SSA_NAME == CST)" is strictly smaller than or
	strictly larger than CST.

testsuite/
	PR tree-optimization/21563
	* gcc.dg/tree-ssa/pr21563.c: New.

From-SVN: r99705

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 23383895a30a61a8fdea212b2190986a0e5a1a2c..2a1eee872854089f8d3f8497a06f93877af05e07 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -3,6 +3,11 @@
        * tree-optimize.c (init_tree_optimization_passes): Move
        pass_cd_dce in place of the last pass_dce.
 
+       PR tree-optimization/21563
+       * tree-vrp.c (compare_value): Return boolean_false_node when
+       SSA_NAME in "if (SSA_NAME == CST)" is strictly smaller than or
+       strictly larger than CST.
+
 2005-05-14  Nathan Sidwell  <nathan@codesourcery.com>
            Jan-Benedict Glaw  <jbglaw@lug-owl.de>
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9124a0d8a5f391f168172007d8651e17b039cecc..09b2cb73e0a14260d2ef533073201fcd62290045 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2005-05-14  Kazu Hirata  <kazu@cs.umass.edu>
+
+       PR tree-optimization/21563
+       * gcc.dg/tree-ssa/pr21563.c: New.
+
 2005-05-14  Jan Hubicka  <jh@suse.cz>
 
        * gcc.dg/noreturn-7.c: Allow control reaches warning.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr21563.c b/gcc/testsuite/gcc.dg/tree-ssa/pr21563.c
new file mode 100644 (file)
index 0000000..b3c4588
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr21563.c
@@ -0,0 +1,17 @@
+/* PR tree-optimization/21563
+   Make sure VRP folds the second "if" statement.  */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-tree-dominator-opts -fdump-tree-vrp-details" } */
+
+int
+foo (int a)
+{
+  if (a > 1)
+    if (a == 0)
+      return 1;
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Folding predicate" 1 "vrp"} } */
+/* { dg-final { cleanup-tree-dump "vrp" } } */

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 8be79b5919c3280611a0ebba2ceed929b748a863..16fa58b23b181fc4993b6db72d6644ca8c1f4846 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1204,6 +1204,9 @@ compare_range_with_value (enum tree_code comp, value_range *vr, tree val)
          else if (cmp == -1 || cmp == 1 || cmp == 2)
            return boolean_false_node;
        }
+      else if (compare_values (val, vr->min) == -1
+              || compare_values (vr->max, val) == -1)
+       return boolean_false_node;
 
       return NULL_TREE;
     }