bader added inline comments.
================ Comment at: lib/Headers/opencl-c.h:16020 +// The macro CLK_NULL_RESERVE_ID refers to an invalid reservation ID. +#define CLK_NULL_RESERVE_ID (__builtin_astype((void *)0, reserve_id_t)) bool __ovld is_valid_reserve_id(reserve_id_t reserve_id); ---------------- yaxunl wrote: > bader wrote: > > yaxunl wrote: > > > bader wrote: > > > > yaxunl wrote: > > > > > yaxunl wrote: > > > > > > bader wrote: > > > > > > > yaxunl wrote: > > > > > > > > Anastasia wrote: > > > > > > > > > echuraev wrote: > > > > > > > > > > yaxunl wrote: > > > > > > > > > > > Anastasia wrote: > > > > > > > > > > > > yaxunl wrote: > > > > > > > > > > > > > Anastasia wrote: > > > > > > > > > > > > > > Looks good from my side. > > > > > > > > > > > > > > > > > > > > > > > > > > > > @yaxunl , since you originally committed this. > > > > > > > > > > > > > > Could you please verify that changing from > > > > > > > > > > > > > > `SIZE_MAX` to `0` would be fine. > > > > > > > > > > > > > > > > > > > > > > > > > > > > Btw, we have a similar definition for > > > > > > > > > > > > > > `CLK_NULL_EVENT`. > > > > > > > > > > > > > `__PIPE_RESERVE_ID_VALID_BIT` is implementation > > > > > > > > > > > > > detail and not part of the spec. I would suggest to > > > > > > > > > > > > > remove it from this header file. > > > > > > > > > > > > > > > > > > > > > > > > > > The spec only requires CLK_NULL_RESERVE_ID to be > > > > > > > > > > > > > defined but does not define its value. Naturally a > > > > > > > > > > > > > valid id starts from 0 and increases. I don't see > > > > > > > > > > > > > significant advantage to change CLK_NULL_RESERVE_ID > > > > > > > > > > > > > from __SIZE_MAX to 0. > > > > > > > > > > > > > > > > > > > > > > > > > > Is there any reason that this change is needed? > > > > > > > > > > > > I don't see issues to commit things outside of spec as > > > > > > > > > > > > soon as they prefixed properly with "__". But I agree > > > > > > > > > > > > it would be nice to see if it's any useful and what the > > > > > > > > > > > > motivation is for having different implementation. > > > > > > > > > > > For `__PIPE_RESERVE_ID_VALID_BIT`, it assumes that the > > > > > > > > > > > implementation uses one specific bit of a reserve id to > > > > > > > > > > > indicate that the reserve id is valid. Not all > > > > > > > > > > > implementations assume that. Actually I am curious why > > > > > > > > > > > that is needed too. > > > > > > > > > > About `CLK_NULL_RESERVE_ID`: we check that reserve id is > > > > > > > > > > valid if significant bit equal to one. `CLK_NULL_RESERVE_ID > > > > > > > > > > refers to an invalid reservation, so if > > > > > > > > > > `CLK_NULL_RESERVE_ID equal to 0, we can be sure that > > > > > > > > > > significant bit doesn't equal to 1 and it is invalid > > > > > > > > > > reserve id. Also it is more obviously if > > > > > > > > > > CLK_**NULL**_RESERVE_ID is equal to 0. > > > > > > > > > > > > > > > > > > > > What about `__PIPE_RESERVE_ID_VALID_BIT`: As I understand > > > > > > > > > > previous implementation also assumes that one specific bit > > > > > > > > > > was of a reverse id was used to indicate that the reserve > > > > > > > > > > id is valid. So, we just increased reserve id size by one > > > > > > > > > > bit on 32-bit platforms and by 33 bits on 64-bit platforms. > > > > > > > > > It is more logical to me that `CLK_NULL_RESERVE_ID` is 0, but > > > > > > > > > spec doesn't define it of course. > > > > > > > > In our implementation, valid reserve id starts at 0 and > > > > > > > > increasing linearly until `__SIZE_MAX-1`. This change will > > > > > > > > break our implementation. > > > > > > > > > > > > > > > > However, we can modify our implementation to adopt this change > > > > > > > > since it brings about benefits overall. > > > > > > > Ideally it would be great to have unified implementation, but we > > > > > > > can define device specific value for CLK_NULL_RESERVE_ID by using > > > > > > > ifdef directive. > > > > > > How about > > > > > > > > > > > > ``` > > > > > > __attribute__((const)) size_t __clk_null_reserve_id(); > > > > > > #define CLK_NULL_RESERVE_ID __clk_null_reserve_id() > > > > > > > > > > > > ``` > > > > > > I think the spec does not require it to be compile time constant. > > > > > > Then each library can implement its own __clk_null_reserve_id() > > > > > > whereas the IR is target independent. > > > > > Or we only do this for SPIR and define it as target specific value > > > > > for other targets. > > > > Defining CLK_NULL_RESERVE_ID as a function call should also work, but > > > > IMHO compile time constant is preferable option. > > > > I don't think making it compile time constant for SPIR only makes sense > > > > to me - in this case we can use constant for all targets. > > > > > > > > How about following approach: use 0 by default and allow other targets > > > > re-define CLK_NULL_RESERVE_ID value. > > > > > > > > ``` > > > > #ifndef CLK_NULL_RESERVE_ID > > > > #define CLK_NULL_RESERVE_ID 0 > > > > #endif // CLK_NULL_RESERVE_ID > > > > ``` > > > > > > > > If CLK_NULL_RESERVE_ID defined via -D command line option or included > > > > before OpenCL C header file (via -include option), the defined value > > > > will be used, otherwise 0. > > > > > > > > Will it work for you? > > > No. That makes us unable to consume SPIR since CLK_NULL_RESERVE_ID is > > > hardcoded as 0 when the source code is translated to SPIR whereas our > > > target expects ~0U. > > > > > > To get a portable IR we need to represent CLK_NULL_RESERVE_ID as a > > > function which can be lowered to a constant by a specific target. > > > > > > > > Do you refer to SPIR-V or SPIR 2.0? > > > > BTW, you also mentioned that it's possible to up modify your implementation > > to align it with proposed version. > > > > > However, we can modify our implementation to adopt this change since it > > > brings about benefits overall. > > > > Is it still an option? > I was talking about SPIR in a general sense. What I said applies to either > SPIR or SPIR-V, as long as we want a portable representation. Currently Clang > does not support SPIR-V, but I guess the header file will be used for SPIR-V > in the future in the similar way as it is used for SPIR. > > Yes, that is still an option. In that case I want a uniform compile-time > constant definition for all targets. > > If we choose to allow each target having its own constant value, then for > SPIR or SPIR-V it needs to be defined as a function. > What I said applies to either SPIR or SPIR-V, as long as we want a portable > representation. ... > If we choose to allow each target having its own constant value, then for > SPIR or SPIR-V it needs to be defined as a function. SPIR-V (as well as OpenCL) doesn't define CLK_NULL_RESERVE_ID, so it's not portable. Replacing it with function call puts additional implicit requirements for the frameworks consuming SPIR-V to provide __clk_null_reserve_id function implementation. > Yes, that is still an option. In that case I want a uniform compile-time > constant definition for all targets. So far, I'm in favor of this option. I think we need to bring this question to the Khronos and either: 1. define uniform compile-time constant 2. make the OpenCL value implementation defined and introduce SPIR-V representation for CLK_NULL_RESERVE_ID https://reviews.llvm.org/D32896 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
