re PR tree-optimization/56790 (VEC_COND_EXPR not constant folded)

2013-04-03  Marc Glisse  <marc.glisse@inria.fr>

	PR tree-optimization/56790
gcc/
	* fold-const.c (fold_ternary_loc) <VEC_COND_EXPR>: Add constant folding.

gcc/testsuite/
	* g++.dg/ext/pr56790-1.C: New testcase.

From-SVN: r197395

gcc/ChangeLog

 2013-04-03  Marc Glisse  <marc.glisse@inria.fr>
 
+	PR tree-optimization/56790
+	* fold-const.c (fold_ternary_loc) <VEC_COND_EXPR>: Add constant folding.
+
+2013-04-03  Marc Glisse  <marc.glisse@inria.fr>
+
 	* simplify-rtx.c (simplify_binary_operation_1) <VEC_SELECT>:
 	Handle VEC_MERGE.
 	(simplify_ternary_operation) <VEC_MERGE>: Use unsigned HOST_WIDE_INT

gcc/fold-const.c

@@ -13924,6 +13924,29 @@ fold_ternary_loc (location_t loc, enum tree_code code, tree type,
 	    return pedantic_omit_one_operand_loc (loc, type, arg1, arg2);
 	  if (integer_zerop (arg0))
 	    return pedantic_omit_one_operand_loc (loc, type, arg2, arg1);
+
+	  if ((TREE_CODE (arg1) == VECTOR_CST
+	       || TREE_CODE (arg1) == CONSTRUCTOR)
+	      && (TREE_CODE (arg2) == VECTOR_CST
+		  || TREE_CODE (arg2) == CONSTRUCTOR))
+	    {
+	      unsigned int nelts = TYPE_VECTOR_SUBPARTS (type), i;
+	      unsigned char *sel = XALLOCAVEC (unsigned char, nelts);
+	      gcc_assert (nelts == VECTOR_CST_NELTS (arg0));
+	      for (i = 0; i < nelts; i++)
+		{
+		  tree val = VECTOR_CST_ELT (arg0, i);
+		  if (integer_all_onesp (val))
+		    sel[i] = i;
+		  else if (integer_zerop (val))
+		    sel[i] = nelts + i;
+		  else /* Currently unreachable.  */
+		    return NULL_TREE;
+		}
+	      tree t = fold_vec_perm (type, arg1, arg2, sel);
+	      if (t != NULL_TREE)
+		return t;
+	    }
 	}
 
       if (operand_equal_p (arg1, op2, 0))

gcc/testsuite/ChangeLog

 2013-04-03  Marc Glisse  <marc.glisse@inria.fr>
 
+	PR tree-optimization/56790
+	* g++.dg/ext/pr56790-1.C: New testcase.
+
+2013-04-03  Marc Glisse  <marc.glisse@inria.fr>
+
 	* gcc.target/i386/merge-1.c: New testcase.
 	* gcc.target/i386/avx2-vpblendd128-1.c: Make it non-trivial.
 

gcc/testsuite/g++.dg/ext/pr56790-1.C

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-ccp1" } */
+
+typedef long vec __attribute__ ((vector_size (2 * sizeof (long))));
+
+vec f (void)
+{
+  vec a = {  5,  7 };
+  vec b = { 11, 13 };
+  vec m = { -1,  0 };
+  return m ? a : b;
+}
+
+/* { dg-final { scan-tree-dump "{ 5, 13 }" "ccp1" } } */
+/* { dg-final { scan-tree-dump-not "VEC_COND_EXPR" "ccp1" } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */