diff options
Diffstat (limited to 'gcc/tree-ssa-phiopt.c')
| -rw-r--r-- | gcc/tree-ssa-phiopt.c | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c index aa6bb88..e2758b2 100644 --- a/gcc/tree-ssa-phiopt.c +++ b/gcc/tree-ssa-phiopt.c @@ -752,7 +752,9 @@ conditional_replacement (basic_block cond_bb, basic_block middle_bb, gimple_stmt_iterator gsi; edge true_edge, false_edge; tree new_var, new_var2; - bool neg; + bool neg = false; + int shift = 0; + tree nonzero_arg; /* FIXME: Gimplification of complex type is too hard for now. */ /* We aren't prepared to handle vectors either (and it is a question @@ -763,14 +765,22 @@ conditional_replacement (basic_block cond_bb, basic_block middle_bb, || POINTER_TYPE_P (TREE_TYPE (arg1)))) return false; - /* The PHI arguments have the constants 0 and 1, or 0 and -1, then - convert it to the conditional. */ - if ((integer_zerop (arg0) && integer_onep (arg1)) - || (integer_zerop (arg1) && integer_onep (arg0))) - neg = false; - else if ((integer_zerop (arg0) && integer_all_onesp (arg1)) - || (integer_zerop (arg1) && integer_all_onesp (arg0))) + /* The PHI arguments have the constants 0 and 1, or 0 and -1 or + 0 and (1 << cst), then convert it to the conditional. */ + if (integer_zerop (arg0)) + nonzero_arg = arg1; + else if (integer_zerop (arg1)) + nonzero_arg = arg0; + else + return false; + if (integer_all_onesp (nonzero_arg)) neg = true; + else if (integer_pow2p (nonzero_arg)) + { + shift = tree_log2 (nonzero_arg); + if (shift && POINTER_TYPE_P (TREE_TYPE (nonzero_arg))) + return false; + } else return false; @@ -782,12 +792,12 @@ conditional_replacement (basic_block cond_bb, basic_block middle_bb, falls through into BB. There is a single PHI node at the join point (BB) and its arguments - are constants (0, 1) or (0, -1). + are constants (0, 1) or (0, -1) or (0, (1 << shift)). So, given the condition COND, and the two PHI arguments, we can rewrite this PHI into non-branching code: - dest = (COND) or dest = COND' + dest = (COND) or dest = COND' or dest = (COND) << shift We use the condition as-is if the argument associated with the true edge has the value one or the argument associated with the @@ -822,6 +832,14 @@ conditional_replacement (basic_block cond_bb, basic_block middle_bb, cond = fold_build1_loc (gimple_location (stmt), NEGATE_EXPR, TREE_TYPE (cond), cond); } + else if (shift) + { + cond = fold_convert_loc (gimple_location (stmt), + TREE_TYPE (result), cond); + cond = fold_build2_loc (gimple_location (stmt), + LSHIFT_EXPR, TREE_TYPE (cond), cond, + build_int_cst (integer_type_node, shift)); + } /* Insert our new statements at the end of conditional block before the COND_STMT. */ |