uweigand wrote: > > I see that the LowerOperationWrapper still emits i128 operations. (E.g. you > > expand a f16->i128 into a f16->f32 and f32->i128) But that routine is > > called because of the illegal input type i128, so I understand it must not > > leave any operations with the illegal type; rather, it should complete the > > expansion fully. > > My understanding is that the TypeLegalizer calls here for i128 > operands/results for Custom operations, even though the target doesn't have > to do anything. If Results is returned empty, TypeLegalizer will try to > handle it. New nodes in Results on the other hand will be visited as well. > > > This is annoying since for legal i128 we do the expansion in LowerOperation > > while for illegal i128 we do it in LowerOperationWrapper.. > > I followed your example of calling LowerOperationWrapper instead to avoid the > code duplication - looks better. >
That's not quite what I was thinking. You now call into LowerOperationWrapper for f16 always - but f16 is always legal so there shouldn't be a need to do that. Instead, the type that is sometimes legal and sometimes not is i128 - so I would have thought the right way to call into LowerOperationWrapper for *i128* always. (For example, when i128 is not legal, where is the libcall even emitted now? LowerOperation shouldn't be called for legal types, and your current LowerOperationWrapper doesn't emit libcalls?) > Added new opcodes for half per what was previously done for float and double. > Special handling needed to remove the fpround for f128 as it would otherwise > be lowered to a libcall. (The fpround for f128 could be removed for float and > double as well, but there are currently no tests for this). This seems to be more suitable for a DAGCombiner rule as it is really a performance optimization. This could also be done as a separate patch (for all the types). https://github.com/llvm/llvm-project/pull/109164 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
