[PATCH] D107795: [AArch64][DAGCombine] Check the legality of the index of EXTRACT_SUBVECTOR

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


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Comment at: llvm/test/CodeGen/AArch64/aarch64-avoid-illegal-extract-subvector.ll:8
+
+define dso_local void @h() local_unnamed_addr {
+; CHECK-LABEL: h:
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RKSimon wrote:
> david-arm wrote:
> > Would it be possible to reduce this test a lot further? It looks like it shouldn't be too difficult to hand-write a new test that does something like:
> > 
> >   %i1 = extractelement <4 x i32> %x, i32 1
> >   %zi1 = zext i32 %i1 to i64
> >   %i2 = extractelement <4 x i32> %x, i32 2
> >   %zi2 = zext i32 %i2 to i64
> >   %v1 = insertelement <2 x i64> undef, %zi1, i32 0
> >   %v2 = insertelement <2 x i64> %v1, %zi2, i32 1
> > 
> > That looks like what the DAG combine is testing for and since the first extract is at index 1 it is not a multiple of the number of elements in the final build vector (<2 x i64>)
> @guopeilin Any luck with simplifying this test?
Can this be cleaned up anymore - the dso_local / local_unnamed_addr attributes seem superfluous for instance.


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