While working on something else I discovered this ICE-on-invalid.
The problem is that when looking into the innermost lexical scope,
gimple_bind_body might be null, so check 'seq' first before checking
its gimple_code.
I factored the code to its own function so that I can simply 'return'.
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2016-06-10 Marek Polacek <pola...@redhat.com>
PR middle-end/71476
* gimplify.c (maybe_warn_switch_unreachable): Factored out of
gimplify_switch_expr.
* gcc.dg/noncompile/pr71476.c: New test.
diff --git gcc/gimplify.c gcc/gimplify.c
index f12c6a1..542e0b2 100644
--- gcc/gimplify.c
+++ gcc/gimplify.c
@@ -1559,6 +1559,50 @@ gimplify_statement_list (tree *expr_p, gimple_seq *pre_p)
return GS_ALL_DONE;
}
+/* Possibly warn about unreachable statements between switch's controlling
+ expression and the first case. SEQ is the body of a switch expression. */
+
+static void
+maybe_warn_switch_unreachable (gimple_seq seq)
+{
+ if (!warn_switch_unreachable
+ /* This warning doesn't play well with Fortran when optimizations
+ are on. */
+ || lang_GNU_Fortran ()
+ || seq == NULL)
+ return;
+
+ /* Look into the innermost lexical scope. */
+ while (seq && gimple_code (seq) == GIMPLE_BIND)
+ seq = gimple_bind_body (as_a <gbind *> (seq));
+
+ /* If it is empty, there's nothing to do. */
+ if (seq == NULL)
+ return;
+
+ gimple *stmt = gimple_seq_first_stmt (seq);
+ if (gimple_code (stmt) == GIMPLE_TRY)
+ {
+ /* A compiler-generated cleanup or a user-written try block.
+ Try to get the first statement in its try-block, for better
+ location. */
+ if ((seq = gimple_try_eval (stmt)))
+ stmt = gimple_seq_first_stmt (seq);
+ }
+
+ if (gimple_code (stmt) != GIMPLE_LABEL)
+ {
+ if (gimple_code (stmt) == GIMPLE_GOTO
+ && TREE_CODE (gimple_goto_dest (stmt)) == LABEL_DECL
+ && DECL_ARTIFICIAL (gimple_goto_dest (stmt)))
+ /* Don't warn for compiler-generated gotos. These occur
+ in Duff's devices, for example. */;
+ else
+ warning_at (gimple_location (stmt), OPT_Wswitch_unreachable,
+ "statement will never be executed");
+ }
+}
+
/* Gimplify a SWITCH_EXPR, and collect the vector of labels it can
branch to. */
@@ -1596,39 +1640,8 @@ gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
gimplify_stmt (&SWITCH_BODY (switch_expr), &switch_body_seq);
- /* Possibly warn about unreachable statements between switch's
- controlling expression and the first case. */
- if (warn_switch_unreachable
- /* This warning doesn't play well with Fortran when optimizations
- are on. */
- && !lang_GNU_Fortran ()
- && switch_body_seq != NULL)
- {
- gimple_seq seq = switch_body_seq;
- /* Look into the innermost lexical scope. */
- while (gimple_code (seq) == GIMPLE_BIND)
- seq = gimple_bind_body (as_a <gbind *> (seq));
- gimple *stmt = gimple_seq_first_stmt (seq);
- if (gimple_code (stmt) == GIMPLE_TRY)
- {
- /* A compiler-generated cleanup or a user-written try block.
- Try to get the first statement in its try-block, for better
- location. */
- if ((seq = gimple_try_eval (stmt)))
- stmt = gimple_seq_first_stmt (seq);
- }
- if (gimple_code (stmt) != GIMPLE_LABEL)
- {
- if (gimple_code (stmt) == GIMPLE_GOTO
- && TREE_CODE (gimple_goto_dest (stmt)) == LABEL_DECL
- && DECL_ARTIFICIAL (gimple_goto_dest (stmt)))
- /* Don't warn for compiler-generated gotos. These occur
- in Duff's devices, for example. */;
- else
- warning_at (gimple_location (stmt), OPT_Wswitch_unreachable,
- "statement will never be executed");
- }
- }
+ maybe_warn_switch_unreachable (switch_body_seq);
+
labels = gimplify_ctxp->case_labels;
gimplify_ctxp->case_labels = saved_labels;
diff --git gcc/testsuite/gcc.dg/noncompile/pr71476.c
gcc/testsuite/gcc.dg/noncompile/pr71476.c
index e69de29..138eeeb 100644
--- gcc/testsuite/gcc.dg/noncompile/pr71476.c
+++ gcc/testsuite/gcc.dg/noncompile/pr71476.c
@@ -0,0 +1,12 @@
+/* PR middle-end/71476 */
+/* { dg-do compile } */
+/* { dg-options "-Wswitch-unreachable" } */
+
+void
+foo (int a)
+{
+ switch (a)
+ {
+ void f (void) { break; } /* { dg-error "break statement not within loop
or switch" } */
+ }
+}
Marek
