2010-11-30 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/46722
	* tree-ssa-math-opts.c (convert_mult_to_fma): Get multiplication
	operands as arguments.
	(execute_optimize_widening_mul): Also handle power of two as
	multiplication.

	* gcc.target/i386/fma4-fma-2.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@167304 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 43 insertions, 11 deletions

diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 7837161e440..435c014ea7c 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -1494,14 +1494,14 @@ convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple stmt,
   return true;
 }
 
-/* Combine the multiplication at MUL_STMT with uses in additions and
-   subtractions to form fused multiply-add operations.  Returns true
-   if successful and MUL_STMT should be removed.  */
+/* Combine the multiplication at MUL_STMT with operands MULOP1 and MULOP2
+   with uses in additions and subtractions to form fused multiply-add
+   operations.  Returns true if successful and MUL_STMT should be removed.  */
 
 static bool
-convert_mult_to_fma (gimple mul_stmt)
+convert_mult_to_fma (gimple mul_stmt, tree op1, tree op2)
 {
-  tree mul_result = gimple_assign_lhs (mul_stmt);
+  tree mul_result = gimple_get_lhs (mul_stmt);
   tree type = TREE_TYPE (mul_result);
   gimple use_stmt, neguse_stmt, fma_stmt;
   use_operand_p use_p;
@@ -1607,7 +1607,7 @@ convert_mult_to_fma (gimple mul_stmt)
     {
       gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
       enum tree_code use_code;
-      tree addop, mulop1, result = mul_result;
+      tree addop, mulop1 = op1, result = mul_result;
       bool negate_p = false;
 
       if (is_gimple_debug (use_stmt))
@@ -1646,7 +1646,6 @@ convert_mult_to_fma (gimple mul_stmt)
 	    negate_p = !negate_p;
 	}
 
-      mulop1 = gimple_assign_rhs1 (mul_stmt);
       if (negate_p)
 	mulop1 = force_gimple_operand_gsi (&gsi,
 					   build1 (NEGATE_EXPR,
@@ -1656,8 +1655,7 @@ convert_mult_to_fma (gimple mul_stmt)
 
       fma_stmt = gimple_build_assign_with_ops3 (FMA_EXPR,
 						gimple_assign_lhs (use_stmt),
-						mulop1,
-						gimple_assign_rhs2 (mul_stmt),
+						mulop1, op2,
 						addop);
       gsi_replace (&gsi, fma_stmt, true);
     }
@@ -1673,6 +1671,7 @@ static unsigned int
 execute_optimize_widening_mul (void)
 {
   basic_block bb;
+  bool cfg_changed = false;
 
   FOR_EACH_BB (bb)
     {
@@ -1690,7 +1689,9 @@ execute_optimize_widening_mul (void)
 		{
 		case MULT_EXPR:
 		  if (!convert_mult_to_widen (stmt)
-		      && convert_mult_to_fma (stmt))
+		      && convert_mult_to_fma (stmt,
+					      gimple_assign_rhs1 (stmt),
+					      gimple_assign_rhs2 (stmt)))
 		    {
 		      gsi_remove (&gsi, true);
 		      release_defs (stmt);
@@ -1706,11 +1707,42 @@ execute_optimize_widening_mul (void)
 		default:;
 		}
 	    }
+	  else if (is_gimple_call (stmt))
+	    {
+	      tree fndecl = gimple_call_fndecl (stmt);
+	      if (fndecl
+		  && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL)
+		{
+		  switch (DECL_FUNCTION_CODE (fndecl))
+		    {
+		      case BUILT_IN_POWF:
+		      case BUILT_IN_POW:
+		      case BUILT_IN_POWL:
+			if (TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
+			    && REAL_VALUES_EQUAL
+			         (TREE_REAL_CST (gimple_call_arg (stmt, 1)),
+				  dconst2)
+			    && convert_mult_to_fma (stmt,
+						    gimple_call_arg (stmt, 0),
+						    gimple_call_arg (stmt, 0)))
+			  {
+			    gsi_remove (&gsi, true);
+			    release_defs (stmt);
+			    if (gimple_purge_dead_eh_edges (bb))
+			      cfg_changed = true;
+			    continue;
+			  }
+			  break;
+
+		      default:;
+		    }
+		}
+	    }
 	  gsi_next (&gsi);
 	}
     }
 
-  return 0;
+  return cfg_changed ? TODO_cleanup_cfg : 0;
 }
 
 static bool