[llvm] [VPlan] Emit VPVectorEndPointerRecipe for reverse interleave pointer adjustment (PR #144864)

[Mel Chen via llvm-commits]

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@@ -381,10 +379,8 @@ define void @test_reversed_load2_store2(ptr noalias nocapture readonly %A, ptr n
 ; CHECK-NEXT:    [[TMP12:%.*]] = add nsw <vscale x 4 x i32> [[REVERSE]], [[VEC_IND]]
 ; CHECK-NEXT:    [[TMP13:%.*]] = sub nsw <vscale x 4 x i32> [[REVERSE1]], [[VEC_IND]]
 ; CHECK-NEXT:    [[TMP14:%.*]] = getelementptr inbounds [[STRUCT_ST2]], ptr [[B:%.*]], i64 [[OFFSET_IDX]], i32 0
-; CHECK-NEXT:    [[TMP15:%.*]] = call i32 @llvm.vscale.i32()
-; CHECK-NEXT:    [[TMP16:%.*]] = shl nuw nsw i32 [[TMP15]], 3
-; CHECK-NEXT:    [[TMP17:%.*]] = sub nsw i32 2, [[TMP16]]
-; CHECK-NEXT:    [[TMP18:%.*]] = sext i32 [[TMP17]] to i64
+; CHECK-NEXT:    [[TMP15:%.*]] = shl nuw nsw i64 [[TMP0]], 3
+; CHECK-NEXT:    [[TMP18:%.*]] = sub nsw i64 2, [[TMP15]]
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Mel-Chen wrote:

The original implementation uses i64 as the index type in the GEP.
I think one reason getGEPIndexTy can't simply choose i32 is due to scalable VF in this case;
another reason is that we compute NumElt = Stride * CurrentPart * RunTimeVF, and if the stride is not unit stride, then we have to use the type determined by datalayout.

https://github.com/llvm/llvm-project/pull/144864