This cleans up unreachable code diagnosed by -Wunreachable-code-ctrl.
It largely follows the previous series but discovers a few extra
cases, namely dead code after break or continue or loops without
exits.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2021-11-29 Richard Biener <rguent...@suse.de>
gcc/c/
* gimple-parser.c (c_parser_gimple_postfix_expression):
avoid unreachable code after break.
gcc/
* cfgrtl.c (skip_insns_after_block): Refactor code to
be more easily readable.
* expr.c (op_by_pieces_d::run): Remove unreachable
assert.
* sched-deps.c (sched_analyze): Remove unreachable
gcc_unreachable.
* sel-sched-ir.c (in_same_ebb_p): Likewise.
* tree-ssa-alias.c (nonoverlapping_refs_since_match_p):
Remove unreachable code.
* tree-vect-slp.c (vectorize_slp_instance_root_stmt):
Refactor to avoid unreachable loop iteration.
* tree.c (walk_tree_1): Remove unreachable break.
* vec-perm-indices.c (vec_perm_indices::series_p): Remove
unreachable return.
gcc/cp/
* parser.c (cp_parser_postfix_expression): Remove
unreachable code.
* pt.c (tsubst_expr): Remove unreachable breaks.
gcc/fortran/
* frontend-passes.c (gfc_expr_walker): Remove unreachable
break.
* scanner.c (skip_fixed_comments): Remove unreachable
gcc_unreachable.
* trans-expr.c (gfc_expr_is_variable): Refactor to make
control flow more obvious.
---
gcc/c/gimple-parser.c | 8 +-------
gcc/cfgrtl.c | 10 ++--------
gcc/cp/parser.c | 4 ----
gcc/cp/pt.c | 2 --
gcc/expr.c | 3 ---
gcc/fortran/frontend-passes.c | 1 -
gcc/fortran/scanner.c | 1 -
gcc/fortran/trans-expr.c | 11 +++--------
gcc/sched-deps.c | 2 --
gcc/sel-sched-ir.c | 3 ---
gcc/tree-ssa-alias.c | 3 ---
gcc/tree-vect-slp.c | 22 ++++++++--------------
gcc/tree.c | 2 --
gcc/vec-perm-indices.c | 1 -
14 files changed, 14 insertions(+), 59 deletions(-)
diff --git a/gcc/c/gimple-parser.c b/gcc/c/gimple-parser.c
index 32f22dbb8a7..f594a8ccb31 100644
--- a/gcc/c/gimple-parser.c
+++ b/gcc/c/gimple-parser.c
@@ -1698,13 +1698,7 @@ c_parser_gimple_postfix_expression (gimple_parser
&parser)
}
break;
}
- else
- {
- c_parser_error (parser, "expected expression");
- expr.set_error ();
- break;
- }
- break;
+ /* Fallthru. */
default:
c_parser_error (parser, "expected expression");
expr.set_error ();
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 3744adcc2ba..287a3db643a 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -3539,14 +3539,8 @@ skip_insns_after_block (basic_block bb)
continue;
case NOTE:
- switch (NOTE_KIND (insn))
- {
- case NOTE_INSN_BLOCK_END:
- gcc_unreachable ();
- default:
- continue;
- }
- break;
+ gcc_assert (NOTE_KIND (insn) != NOTE_INSN_BLOCK_END);
+ continue;
case CODE_LABEL:
if (NEXT_INSN (insn)
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 0bd58525726..cc88a36dd39 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -7892,10 +7892,6 @@ cp_parser_postfix_expression (cp_parser *parser, bool
address_p, bool cast_p,
return postfix_expression;
}
}
-
- /* We should never get here. */
- gcc_unreachable ();
- return error_mark_node;
}
/* Helper function for cp_parser_parenthesized_expression_list and
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 31ed773e145..f4b9d9673fb 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18242,13 +18242,11 @@ tsubst_expr (tree t, tree args, tsubst_flags_t
complain, tree in_decl,
stmt = finish_co_yield_expr (input_location,
RECUR (TREE_OPERAND (t, 0)));
RETURN (stmt);
- break;
case CO_AWAIT_EXPR:
stmt = finish_co_await_expr (input_location,
RECUR (TREE_OPERAND (t, 0)));
RETURN (stmt);
- break;
case EXPR_STMT:
tmp = RECUR (EXPR_STMT_EXPR (t));
diff --git a/gcc/expr.c b/gcc/expr.c
index 5673902b1fc..b2815257509 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -1342,9 +1342,6 @@ op_by_pieces_d::run ()
}
}
while (1);
-
- /* The code above should have handled everything. */
- gcc_assert (!length);
}
/* Derived class from op_by_pieces_d, providing support for block move
diff --git a/gcc/fortran/frontend-passes.c b/gcc/fortran/frontend-passes.c
index f5ba7cecd54..16ee2afc9c0 100644
--- a/gcc/fortran/frontend-passes.c
+++ b/gcc/fortran/frontend-passes.c
@@ -5229,7 +5229,6 @@ gfc_expr_walker (gfc_expr **e, walk_expr_fn_t exprfn,
void *data)
case EXPR_OP:
WALK_SUBEXPR ((*e)->value.op.op1);
WALK_SUBEXPR_TAIL ((*e)->value.op.op2);
- break;
case EXPR_FUNCTION:
for (a = (*e)->value.function.actual; a; a = a->next)
WALK_SUBEXPR (a->expr);
diff --git a/gcc/fortran/scanner.c b/gcc/fortran/scanner.c
index 69b81ab97f8..4d72ff78543 100644
--- a/gcc/fortran/scanner.c
+++ b/gcc/fortran/scanner.c
@@ -1159,7 +1159,6 @@ skip_fixed_comments (void)
skip_comment_line ();
continue;
- gcc_unreachable ();
check_for_digits:
{
/* Required for OpenMP's conditional compilation sentinel. */
diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index bc502c0f43c..e413b2d7a1f 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -11079,14 +11079,9 @@ gfc_expr_is_variable (gfc_expr *expr)
func_ifc = expr->value.function.esym;
goto found_ifc;
}
- else
- {
- gcc_assert (expr->symtree);
- func_ifc = expr->symtree->n.sym;
- goto found_ifc;
- }
-
- gcc_unreachable ();
+ gcc_assert (expr->symtree);
+ func_ifc = expr->symtree->n.sym;
+ goto found_ifc;
}
comp = gfc_get_proc_ptr_comp (expr);
diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
index 5814204c681..62aa47a73bd 100644
--- a/gcc/sched-deps.c
+++ b/gcc/sched-deps.c
@@ -3816,7 +3816,6 @@ sched_analyze (class deps_desc *deps, rtx_insn *head,
rtx_insn *tail)
for (insn = head;; insn = NEXT_INSN (insn))
{
-
if (INSN_P (insn))
{
/* And initialize deps_lists. */
@@ -3836,7 +3835,6 @@ sched_analyze (class deps_desc *deps, rtx_insn *head,
rtx_insn *tail)
return;
}
}
- gcc_unreachable ();
}
/* Helper for sched_free_deps ().
diff --git a/gcc/sel-sched-ir.c b/gcc/sel-sched-ir.c
index 48965bfb0ad..b76a48eb16e 100644
--- a/gcc/sel-sched-ir.c
+++ b/gcc/sel-sched-ir.c
@@ -4918,9 +4918,6 @@ in_same_ebb_p (insn_t insn, insn_t succ)
ptr = bb_next_bb (ptr);
}
-
- gcc_unreachable ();
- return false;
}
/* Recomputes the reverse topological order for the function and
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 3c253e2843f..88fd7821c5e 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -1800,9 +1800,6 @@ nonoverlapping_refs_since_match_p (tree match1, tree ref1,
return 1;
}
}
-
- ++alias_stats.nonoverlapping_refs_since_match_p_must_overlap;
- return 0;
}
/* Return TYPE_UID which can be used to match record types we consider
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 94c75497495..cfea0c80be3 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -7311,20 +7311,14 @@ vectorize_slp_instance_root_stmt (slp_tree node,
slp_instance instance)
{
if (SLP_TREE_NUMBER_OF_VEC_STMTS (node) == 1)
{
- gimple *child_stmt;
- int j;
-
- FOR_EACH_VEC_ELT (SLP_TREE_VEC_STMTS (node), j, child_stmt)
- {
- tree vect_lhs = gimple_get_lhs (child_stmt);
- tree root_lhs = gimple_get_lhs (instance->root_stmts[0]->stmt);
- if (!useless_type_conversion_p (TREE_TYPE (root_lhs),
- TREE_TYPE (vect_lhs)))
- vect_lhs = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (root_lhs),
- vect_lhs);
- rstmt = gimple_build_assign (root_lhs, vect_lhs);
- break;
- }
+ gimple *child_stmt = SLP_TREE_VEC_STMTS (node)[0];
+ tree vect_lhs = gimple_get_lhs (child_stmt);
+ tree root_lhs = gimple_get_lhs (instance->root_stmts[0]->stmt);
+ if (!useless_type_conversion_p (TREE_TYPE (root_lhs),
+ TREE_TYPE (vect_lhs)))
+ vect_lhs = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (root_lhs),
+ vect_lhs);
+ rstmt = gimple_build_assign (root_lhs, vect_lhs);
}
else if (SLP_TREE_NUMBER_OF_VEC_STMTS (node) > 1)
{
diff --git a/gcc/tree.c b/gcc/tree.c
index 910fb06d6f5..4d91fdea758 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -11127,7 +11127,6 @@ walk_tree_1 (tree *tp, walk_tree_fn func, void *data,
case TREE_LIST:
WALK_SUBTREE (TREE_VALUE (*tp));
WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
- break;
case TREE_VEC:
{
@@ -11206,7 +11205,6 @@ walk_tree_1 (tree *tp, walk_tree_fn func, void *data,
WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, i));
WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
}
- break;
case TARGET_EXPR:
{
diff --git a/gcc/vec-perm-indices.c b/gcc/vec-perm-indices.c
index 31b32ea0589..9e6b5af327c 100644
--- a/gcc/vec-perm-indices.c
+++ b/gcc/vec-perm-indices.c
@@ -228,7 +228,6 @@ vec_perm_indices::series_p (unsigned int out_base, unsigned
int out_step,
out_base += out_step;
}
- return true;
}
/* Return true if all elements of the permutation vector are in the range
