diff options
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 56 |
1 files changed, 55 insertions, 1 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index d51acaa..0439272 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -7466,7 +7466,8 @@ compare_names (enum tree_code comp, tree n1, tree n2, return NULL_TREE; } -/* Helper function for vrp_evaluate_conditional_warnv. */ +/* Helper function for vrp_evaluate_conditional_warnv & other + optimizers. */ static tree vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code, @@ -9145,6 +9146,54 @@ simplify_div_or_mod_using_ranges (gimple stmt) return false; } +/* Simplify a min or max if the ranges of the two operands are + disjoint. Return true if we do simplify. */ + +static bool +simplify_min_or_max_using_ranges (gimple stmt) +{ + tree op0 = gimple_assign_rhs1 (stmt); + tree op1 = gimple_assign_rhs2 (stmt); + bool sop = false; + tree val; + + val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges + (LE_EXPR, op0, op1, &sop)); + if (!val) + { + sop = false; + val = (vrp_evaluate_conditional_warnv_with_ops_using_ranges + (LT_EXPR, op0, op1, &sop)); + } + + if (val) + { + if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC)) + { + location_t location; + + if (!gimple_has_location (stmt)) + location = input_location; + else + location = gimple_location (stmt); + warning_at (location, OPT_Wstrict_overflow, + "assuming signed overflow does not occur when " + "simplifying %<min/max (X,Y)%> to %<X%> or %<Y%>"); + } + + /* VAL == TRUE -> OP0 < or <= op1 + VAL == FALSE -> OP0 > or >= op1. */ + tree res = ((gimple_assign_rhs_code (stmt) == MAX_EXPR) + == integer_zerop (val)) ? op0 : op1; + gimple_stmt_iterator gsi = gsi_for_stmt (stmt); + gimple_assign_set_rhs_from_tree (&gsi, res); + update_stmt (stmt); + return true; + } + + return false; +} + /* If the operand to an ABS_EXPR is >= 0, then eliminate the ABS_EXPR. If the operand is <= 0, then simplify the ABS_EXPR into a NEGATE_EXPR. */ @@ -9987,6 +10036,11 @@ simplify_stmt_using_ranges (gimple_stmt_iterator *gsi) return simplify_float_conversion_using_ranges (gsi, stmt); break; + case MIN_EXPR: + case MAX_EXPR: + return simplify_min_or_max_using_ranges (stmt); + break; + default: break; } |