re PR tree-optimization/46722 (Missed fma for x*x + y)

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.

From-SVN: r167304

gcc/ChangeLog

+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.
+
 2010-11-30  Dave Korn  <dave.korn.cygwin@gmail.com>
 
 	PR middle-end/46709

gcc/testsuite/ChangeLog

+2010-11-30  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/46722
+	* gcc.target/i386/fma4-fma-2.c: New testcase.
+
 2010-11-29  Nicola Pero  <nicola.pero@meta-innovation.com>
 
 	* objc.dg/duplicate-class-1.m: New.

gcc/testsuite/gcc.target/i386/fma4-fma-2.c

+/* Test that the compiler properly optimizes floating point multiply
+   and add instructions into vfmaddss, vfmsubss, vfnmaddss,
+   vfnmsubss on FMA4 systems.  */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target lp64 } */
+/* { dg-options "-O2 -funsafe-math-optimizations -mfma4" } */
+
+extern void exit (int);
+
+float
+flt_mul_add (float a, float c)
+{
+  return (a * a) + c;
+}
+
+double
+dbl_mul_add (double a, double c)
+{
+  return (a * a) + c;
+}
+
+float
+flt_mul_sub (float a, float c)
+{
+  return (a * a) - c;
+}
+
+double
+dbl_mul_sub (double a, double c)
+{
+  return (a * a) - c;
+}
+
+float
+flt_neg_mul_add (float a, float c)
+{
+  return (-(a * a)) + c;
+}
+
+double
+dbl_neg_mul_add (double a, double c)
+{
+  return (-(a * a)) + c;
+}
+
+float  f[10] = { 2, 3, 4 };
+double d[10] = { 2, 3, 4 };
+
+int main ()
+{
+  f[3] = flt_mul_add (f[0], f[2]);
+  f[4] = flt_mul_sub (f[0], f[2]);
+  f[5] = flt_neg_mul_add (f[0], f[2]);
+
+  d[3] = dbl_mul_add (d[0], d[2]);
+  d[4] = dbl_mul_sub (d[0], d[2]);
+  d[5] = dbl_neg_mul_add (d[0], d[2]);
+  exit (0);
+}
+
+/* { dg-final { scan-assembler "vfmaddss" } } */
+/* { dg-final { scan-assembler "vfmaddsd" } } */
+/* { dg-final { scan-assembler "vfmsubss" } } */
+/* { dg-final { scan-assembler "vfmsubsd" } } */
+/* { dg-final { scan-assembler "vfnmaddss" } } */
+/* { dg-final { scan-assembler "vfnmaddsd" } } */

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