Prathamesh Kulkarni
2015-11-08 17:39:20 UTC
== This week ==
* TCWG-72 (6/10)
- 5 iterations since the original patch. Changes include:
a) Integration into widening_mul patch
b) Rewriting the divmod transform so DIVMOD() is placed before the topmost
div/mod stmt
c) Removed check for widening mode and optab handler check in expand_DIVMOD
d) Fixed ICE when constant is one of the operands to div/mod stmt.
e) Fixed mis-compilation with a test-case when operands matched but in
opposite order.
f) Formatting nits and fixed test-cases.
- Richard suggested no need to check for post-domination conditions.
- Not sure on what condition to gate the transform.
Checking for availability of divmod/div/mod is not sufficient because arm
defines optab handler for mod which only matches r0 % n where n is
constant and power of 2
for other cases it's expanded via divmod libcall thru expand_divmod.
We would rather need
to check if the template for mod/div gets matched than just to check
if optab handler exists.
AFAIK this cannot be done during tree-ssa passes.
I can think of two approaches:
a) Do the transform to DIVMOD representation unconditionally in
widening_mul pass.
And then in expand_DIVMOD check if the template for mod can be matched.
If it does match then undo the transform from DIVMOD to original
representation and expand.
I am not sure how feasible it is to undo the transform at expansion
time, and start expanding the modified cfg.
b) Define a new target hook combine_divmod.
Default implementation could check for optab handler for div/mod/divmod.
and I could override it for arm-backend to additionally check if the
second operand is a constant and power of 2 and fail for this case
(since we want this to be expanded from modsi3 pattern).
Not sure if this is a good idea, I am replicating the information from
the modsi3 pattern.
If the pattern changes, the hook would also need to be changed.
* Convert ASM_FORMAT_PRIVATE_NAME to hook (2/10)
* TCWG-319 (1/10)
- Bencharmking for patch in progress
* Misc (1/10)
- Meetings
- Sync with Kugan
== Next Week ==
- Continue with TCWG-72
- Complete the patch with build, test and config-builds for
ASM_FROMAT_PRIVATE_NAME and submit upstream
- Continue benchmarking TCWG-319, TCWG-310
* TCWG-72 (6/10)
- 5 iterations since the original patch. Changes include:
a) Integration into widening_mul patch
b) Rewriting the divmod transform so DIVMOD() is placed before the topmost
div/mod stmt
c) Removed check for widening mode and optab handler check in expand_DIVMOD
d) Fixed ICE when constant is one of the operands to div/mod stmt.
e) Fixed mis-compilation with a test-case when operands matched but in
opposite order.
f) Formatting nits and fixed test-cases.
- Richard suggested no need to check for post-domination conditions.
- Not sure on what condition to gate the transform.
Checking for availability of divmod/div/mod is not sufficient because arm
defines optab handler for mod which only matches r0 % n where n is
constant and power of 2
for other cases it's expanded via divmod libcall thru expand_divmod.
We would rather need
to check if the template for mod/div gets matched than just to check
if optab handler exists.
AFAIK this cannot be done during tree-ssa passes.
I can think of two approaches:
a) Do the transform to DIVMOD representation unconditionally in
widening_mul pass.
And then in expand_DIVMOD check if the template for mod can be matched.
If it does match then undo the transform from DIVMOD to original
representation and expand.
I am not sure how feasible it is to undo the transform at expansion
time, and start expanding the modified cfg.
b) Define a new target hook combine_divmod.
Default implementation could check for optab handler for div/mod/divmod.
and I could override it for arm-backend to additionally check if the
second operand is a constant and power of 2 and fail for this case
(since we want this to be expanded from modsi3 pattern).
Not sure if this is a good idea, I am replicating the information from
the modsi3 pattern.
If the pattern changes, the hook would also need to be changed.
* Convert ASM_FORMAT_PRIVATE_NAME to hook (2/10)
* TCWG-319 (1/10)
- Bencharmking for patch in progress
* Misc (1/10)
- Meetings
- Sync with Kugan
== Next Week ==
- Continue with TCWG-72
- Complete the patch with build, test and config-builds for
ASM_FROMAT_PRIVATE_NAME and submit upstream
- Continue benchmarking TCWG-319, TCWG-310