| Message ID | 20161110144520.24965-4-luc.vanoostenryck@gmail.com (mailing list archive) |
|---|---|
| State | Mainlined, archived |
| Headers | show |
On Thu, Nov 10, 2016 at 10:45 PM, Luc Van Oostenryck <luc.vanoostenryck@gmail.com> wrote: > The patch fix this by simply moving the code handling the statement out > of the conditional part processing used labels. Great catch. Applied. Chris -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/linearize.c b/linearize.c index c6ada1e8..4dc3d04d 100644 --- a/linearize.c +++ b/linearize.c @@ -2026,8 +2026,8 @@ pseudo_t linearize_statement(struct entrypoint *ep, struct statement *stmt) if (label->used) { add_label(ep, label); - linearize_statement(ep, stmt->label_statement); } + linearize_statement(ep, stmt->label_statement); break; } diff --git a/validation/discarded-label-statement.c b/validation/discarded-label-statement.c new file mode 100644 index 00000000..b4e58ac6 --- /dev/null +++ b/validation/discarded-label-statement.c @@ -0,0 +1,24 @@ +/* + * Verify that the statement following an unused label + * is not discarded with the label. + */ + +static int bad(int a, int b) +{ + int r = 0; + +start: + r += a; + r += b; + + return r; +} + +/* + * check-name: discarded-label-statement + * check-command: test-linearize $file + * + * check-output-ignore + * check-output-contains: add + * check-output-contains: %arg1 + */
When code contains an unused label, it's not needed to create a new basic block for the code that follow it but that doesn't mean that the following code is unreachable. There is currently a bug related to this when processing a label statement for a label that is never used: not only the label is ignored (and this no new basic block is created) but the whol statement is ignored. In other words the statement directly following an unused label is simply ignored. The patch fix this by simply moving the code handling the statement out of the conditional part processing used labels. Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> --- linearize.c | 2 +- validation/discarded-label-statement.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+), 1 deletion(-) create mode 100644 validation/discarded-label-statement.c