diff --git a/gcc/ChangeLog b/gcc/ChangeLog index e261305f13f6b3cc5e42dce86417fa883e275972..b5ae15e141bc68eaff47cc16878bf6f9f2f4184c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2008-04-29 Richard Guenther <rguenther@suse.de> + + PR middle-end/15255 + * fold-const.c (fold_binary): Fold (A + A) * C to A * 2*C. + 2008-04-29 Richard Guenther <rguenther@suse.de> * tree-ssa-alias.c (finalize_ref_all_pointers): Remove. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index aae203777289cb5e39a4dc9799af674705a27714..b4645ca256e874bdcd3b920c3e5ac3d9afa98169 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -10154,6 +10154,17 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) return fold_build2 (LSHIFT_EXPR, type, op1, TREE_OPERAND (arg0, 1)); + /* (A + A) * C -> A * 2 * C */ + if (TREE_CODE (arg0) == PLUS_EXPR + && TREE_CODE (arg1) == INTEGER_CST + && operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg0, 1), 0)) + return fold_build2 (MULT_EXPR, type, + omit_one_operand (type, TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg0, 1)), + fold_build2 (MULT_EXPR, type, + build_int_cst (type, 2) , arg1)); + strict_overflow_p = false; if (TREE_CODE (arg1) == INTEGER_CST && 0 != (tem = extract_muldiv (op0, arg1, code, NULL_TREE, diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index f2b69e90afca2484067642d0d7f7291653c7d5bf..dd8b3aee01c2afd8e7acdbe25c2806efc6ac884d 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2008-04-29 Richard Guenther <rguenther@suse.de> + + PR middle-end/15255 + * gcc.dg/fold-plusmult.c: New testcase. + 2008-04-29 Richard Guenther <rguenther@suse.de> PR middle-end/36077 diff --git a/gcc/testsuite/gcc.dg/fold-plusmult.c b/gcc/testsuite/gcc.dg/fold-plusmult.c new file mode 100644 index 0000000000000000000000000000000000000000..d584b95887466e50202bf49dd5cf74e7a5c0a647 --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-plusmult.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-fdump-tree-original" } */ + +int test1 (int a) +{ + return 2*a + 2*a; +} + +int test2 (int a) +{ + return (a + a)*2; +} + +/* { dg-final { scan-tree-dump-times "<a> \\\* 4" 2 "original" } } */ +/* { dg-final { cleanup-tree-dump "original" } } */