diff options
Diffstat (limited to 'gcc/tree-ssa-dom.c')
| -rw-r--r-- | gcc/tree-ssa-dom.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c index b0d56fc..17c852d 100644 --- a/gcc/tree-ssa-dom.c +++ b/gcc/tree-ssa-dom.c @@ -913,21 +913,26 @@ simplify_stmt_for_jump_threading (gimple *stmt, find_case_label_range (switch_stmt, vr->min (), vr->max (), &i, &j); + /* Is there only one such label? */ if (i == j) { tree label = gimple_switch_label (switch_stmt, i); tree singleton; + /* The i'th label will only be taken if the value range of the + operand is entirely within the bounds of this label. */ if (CASE_HIGH (label) != NULL_TREE ? (tree_int_cst_compare (CASE_LOW (label), vr->min ()) <= 0 && tree_int_cst_compare (CASE_HIGH (label), vr->max ()) >= 0) : (vr->singleton_p (&singleton) && tree_int_cst_equal (CASE_LOW (label), singleton))) return label; - - if (i > j) - return gimple_switch_label (switch_stmt, 0); } + + /* If there are no such labels, then the default label + will be taken. */ + if (i > j) + return gimple_switch_label (switch_stmt, 0); } if (vr->kind () == VR_ANTI_RANGE) |