[llvm] [VPlan] Consistently use (Part, 0) for first lane scalar values (PR #80271)

[Florian Hahn via llvm-commits]

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@@ -116,8 +116,7 @@ define void @test_widen(ptr noalias %a, ptr readnone %b) #4 {
 ; TFA_INTERLEAVE-NEXT:    [[TMP18:%.*]] = getelementptr inbounds i64, ptr [[TMP15]], i64 [[TMP17]]
 ; TFA_INTERLEAVE-NEXT:    call void @llvm.masked.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP13]], ptr [[TMP15]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK]])
 ; TFA_INTERLEAVE-NEXT:    call void @llvm.masked.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP14]], ptr [[TMP18]], i32 8, <vscale x 2 x i1> [[ACTIVE_LANE_MASK2]])
-; TFA_INTERLEAVE-NEXT:    [[INDEX_NEXT:%.*]] = add i64 [[INDEX]], [[TMP6]]
-; TFA_INTERLEAVE-NEXT:    [[INDEX_NEXT4]] = add i64 [[INDEX]], [[TMP6]]
+; TFA_INTERLEAVE-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], [[TMP6]]
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fhahn wrote:

Missed that one, sorry!

This was an accidental change and has been undone now. To catch this, `onlyFirstPartUsed` needs to also support `CanonicalIVIncrementForPart`, which can be adjusted separately.

https://github.com/llvm/llvm-project/pull/80271