On 03/26/14 12:28, Jakub Jelinek wrote:
On Wed, Mar 26, 2014 at 12:17:43PM -0600, Jeff Law wrote:
On 03/26/14 12:12, Jakub Jelinek wrote:
On Wed, Mar 26, 2014 at 11:02:48AM -0600, Jeff Law wrote:
Bootstrapped and regression tested on x86_64-unknown-linux-gnu.
Verified it fixes the original and reduced testcase.
Note, the testcase is missing from your patch.
But I'd question if this is the right place to canonicalize it.
The non-canonical order seems to be created in the generic code, where
do_tablejump does:
No, at that point it's still canonical because the x86 backend
hasn't simpified the (mult ...) subexpression. Its the
simplification of that subexpression to a constant that creates the
non-canonical RTL. That's why I fixed the x86 bits -- those are the
bits that simplify the (mult ...) into a (const_int) and thus
creates the non-canonical RTL.
(mult:SI (const_int 0) (const_int 4)) is IMHO far from being canonical.
It's debatable. Our canonicalization rules don't explicitly cover the
case where both arguments to a commutative expression are constants.
Thus, I would classify that as legitimate, but unsimplified RTL.
Contrast to
(plus (const_int 0) (label_ref)
Which is clearly non-canonical.
Jeff
