search for: reducebuildvectoshuffle

Displaying 2 results from an estimated 2 matches for "reducebuildvectoshuffle".

2018 Apr 09
2
A way to opt out of a dag combine?
...be erased by git merge and generally doesn't look ideal. Writing the inverse transform in target specific code doesn't work in this instance and in general creates an infinite loop. Guidance would be very welcome! Thanks For the curious, the specific instance I would like to avoid is reduceBuildVecToShuffle. It doesn't seem to have any target specific hooks. Exhaustive testing of x86-64 vector code doesn't show the error. I think the other in tree targets would notice the vector transform getting the answer wrong (it's harder to confirm without hardware), so the bug is probably inert for i...
2018 Apr 09
1
llvm-dev Digest, Vol 166, Issue 22
...his. Thank you >From your description it seems like you are seeing an incorrect behavior. If that's the case, it should definitely be fixed. Could you provide the complete DAG before and after the erroneous transformation? -Krzysztof Combining: t25: v2i16 = BUILD_VECTOR t27, t22 Before reduceBuildVecToShuffle SelectionDAG has 14 nodes: t0: ch = EntryToken t2: v4i16,ch = CopyFromReg t0, Register:v4i16 %0 // [a b c d] t26: v2i16 = extract_subvector t2, Constant:i32<0> // [a b] t27: i16 = extract_vector_elt t26, Constant:i32<0> // [a] t21: v2i16 = extract_subvect...