2012-04-16 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/52975
	* tree-ssa-forwprop.c (combine_cond_exprs): New function.
	(ssa_forward_propagate_and_combine): Call it for COND_EXPRs
	and VEC_COND_EXPRs.  Also combine into VEC_COND_EXPRs condition.
	* fold-const.c (operand_equal_p): Handle TARGET_MEM_REF.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@186488 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 55 insertions, 1 deletions

diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 57b93cee7f1..3e2371bc83c 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -632,6 +632,58 @@ forward_propagate_into_cond (gimple_stmt_iterator *gsi_p)
   return 0;
 }
 
+/* Propagate from the ssa name definition statements of COND_EXPR
+   values in the rhs of statement STMT into the conditional arms
+   if that simplifies it.
+   Returns true if the stmt was changed.  */
+
+static bool
+combine_cond_exprs (gimple_stmt_iterator *gsi_p)
+{
+  gimple stmt = gsi_stmt (*gsi_p);
+  tree cond, val1, val2;
+  bool changed = false;
+
+  cond = gimple_assign_rhs1 (stmt);
+  val1 = gimple_assign_rhs2 (stmt);
+  if (TREE_CODE (val1) == SSA_NAME)
+    {
+      gimple def_stmt = SSA_NAME_DEF_STMT (val1);
+      if (is_gimple_assign (def_stmt)
+	  && gimple_assign_rhs_code (def_stmt) == gimple_assign_rhs_code (stmt)
+	  && operand_equal_p (gimple_assign_rhs1 (def_stmt), cond, 0))
+	{
+	  val1 = unshare_expr (gimple_assign_rhs2 (def_stmt));
+	  gimple_assign_set_rhs2 (stmt, val1);
+	  changed = true;
+	}
+    }
+  val2 = gimple_assign_rhs3 (stmt);
+  if (TREE_CODE (val2) == SSA_NAME)
+    {
+      gimple def_stmt = SSA_NAME_DEF_STMT (val2);
+      if (is_gimple_assign (def_stmt)
+	  && gimple_assign_rhs_code (def_stmt) == gimple_assign_rhs_code (stmt)
+	  && operand_equal_p (gimple_assign_rhs1 (def_stmt), cond, 0))
+	{
+	  val2 = unshare_expr (gimple_assign_rhs3 (def_stmt));
+	  gimple_assign_set_rhs3 (stmt, val2);
+	  changed = true;
+	}
+    }
+  if (operand_equal_p (val1, val2, 0))
+    {
+      gimple_assign_set_rhs_from_tree (gsi_p, val1);
+      stmt = gsi_stmt (*gsi_p);
+      changed = true;
+    }
+
+  if (changed)
+    update_stmt (stmt);
+
+  return changed;
+}
+
 /* We've just substituted an ADDR_EXPR into stmt.  Update all the
    relevant data structures to match.  */
 
@@ -2480,10 +2532,12 @@ ssa_forward_propagate_and_combine (void)
 		     || code == NEGATE_EXPR)
 		    && TREE_CODE (rhs1) == SSA_NAME)
 		  changed = simplify_not_neg_expr (&gsi);
-		else if (code == COND_EXPR)
+		else if (code == COND_EXPR
+			 || code == VEC_COND_EXPR)
 		  {
 		    /* In this case the entire COND_EXPR is in rhs1. */
 		    changed |= forward_propagate_into_cond (&gsi);
+		    changed |= combine_cond_exprs (&gsi);
 		    stmt = gsi_stmt (gsi);
 		  }
 		else if (TREE_CODE_CLASS (code) == tcc_comparison)