Rsync hard-links when modification times are different

Question

I have a large remote directory A and local directory B that are nearly identical in content, though many of the modification times may have changed by copying files etc. I want to create a local directory C with identical content to A, hard-linking to files in B whenever the content is the same. I don't care about getting the modification times the same.

Is this possible with rsync?

For a test case, I have the following local setup (I assume the behavior won't change when A is on a remote server):

[Compputer:/tmp] % cat A/a B/a
foo
foo

[Compputer:/tmp] % rsync -rIv --link-dest=$PWD/B/ /tmp/A/ /tmp/C  
building file list ... done
created directory /tmp/C
./
a
b

sent 169 bytes  received 71 bytes  480.00 bytes/sec
total size is 8  speedup is 0.03

[Compputer:/tmp] % ls -lT A B C
A:
total 16
-rw-r--r--  1 ken  wheel  4 May 28 00:01:15 2016 a
-rw-r--r--  1 ken  wheel  4 May 28 00:01:22 2016 b

B:
total 8
-rw-r--r--  1 ken  wheel  4 May 28 00:01:34 2016 a

C:
total 16
-rw-r--r--  1 ken  wheel  4 May 28 20:46:31 2016 a
-rw-r--r--  1 ken  wheel  4 May 28 20:46:31 2016 b

Notice that a isn't hardlinked.

Answer 1

Found a solution: the -c switch requests that a checksum be compared for every file. That ignores the last-modified dates, and rsync (usually) detects identical files better (at the expense of reading every file in full, but still not needing to transfer over the network).

[Compputer:/tmp] % rsync -rcv --link-dest=$PWD/B/ A/ C
building file list ... done
created directory C
./
b

sent 150 bytes  received 48 bytes  396.00 bytes/sec
total size is 8  speedup is 0.04
[Compputer:/tmp] % ls -l A B C
A:
total 16
-rw-r--r--  1 ken  wheel  4 May 28 00:01 a
-rw-r--r--  1 ken  wheel  4 May 28 00:01 b

B:
total 8
-rw-r--r--  2 ken  wheel  4 May 28 00:01 a

C:
total 16
-rw-r--r--  2 ken  wheel  4 May 28 00:01 a
-rw-r--r--  1 ken  wheel  4 May 30 21:33 b

The 2 before the a files in B/ and C/ indicates that they are hard linked.