[llvm] [InstCombine] Unpack scalable struct loads/stores. (PR #123986)

[Nikita Popov via llvm-commits]

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@@ -722,11 +718,19 @@ static Instruction *unpackLoadToAggregate(InstCombinerImpl &IC, LoadInst &LI) {
         Zero,
         ConstantInt::get(IdxType, i),
       };
-      auto *Ptr = IC.Builder.CreateInBoundsGEP(ST, Addr, ArrayRef(Indices),
-                                               Name + ".elt");
+      auto *Ptr = !SL->getSizeInBits().isScalable()
+                      ? IC.Builder.CreateInBoundsGEP(
+                            ST, Addr, ArrayRef(Indices), Name + ".elt")
+                      : IC.Builder.CreateInBoundsPtrAdd(
+                            Addr,
+                            IC.Builder.CreateVScale(ConstantInt::get(
+                                DL.getIndexType(Addr->getType()),
+                                SL->getElementOffset(i).getKnownMinValue())),
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nikic wrote:

Use `IRBuilder::CreateTypeSize()` and then you can use the same code for scalable and not?

https://github.com/llvm/llvm-project/pull/123986