At -O2, code in the form
if (p) A; B; if (p) C;
may be rearranged via "jump threading" into
if (p) { A; B; C; } else { B; }
But at -O1 this doesn't happen and we -Werror out here on
the "may be used uninitialized" orig_len. Perform this transform
by hand so that -O1 remains a viable debugging alternative.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
util/iov.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/util/iov.c b/util/iov.c
index cc6e837..a92eb3a 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -146,7 +146,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov,
unsigned iov_cnt,
{
ssize_t total = 0;
ssize_t ret;
- size_t orig_len, tail;
+ size_t tail;
unsigned niov;
while (bytes > 0) {
@@ -174,21 +174,22 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov,
unsigned iov_cnt,
for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) {
tail -= iov[niov].iov_len;
}
+
if (tail) {
/* second, fixup the last element, and remember the original
* length */
+ size_t orig_len = iov[niov].iov_len;
assert(niov < iov_cnt);
- assert(iov[niov].iov_len > tail);
- orig_len = iov[niov].iov_len;
+ assert(orig_len > tail);
iov[niov++].iov_len = tail;
- }
- ret = do_send_recv(sockfd, iov, niov, do_send);
+ ret = do_send_recv(sockfd, iov, niov, do_send);
- /* Undo the changes above before checking for errors */
- if (tail) {
iov[niov-1].iov_len = orig_len;
+ } else {
+ ret = do_send_recv(sockfd, iov, niov, do_send);
}
+
if (offset) {
iov[0].iov_base -= offset;
iov[0].iov_len += offset;
--
1.8.1.4
