[clang] [Clang][AArch64][SVE] Allow write to SVE vector elements using the subscript operator (PR #91965)

[Momchil Velikov via cfe-commits]

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@@ -4180,8 +4180,10 @@ LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
 
   // If the base is a vector type, then we are forming a vector element lvalue
   // with this subscript.
-  if (E->getBase()->getType()->isVectorType() &&
-      !isa<ExtVectorElementExpr>(E->getBase())) {
+  if (QualType BaseTy = E->getBase()->getType();
+      (BaseTy->isVectorType() && !isa<ExtVectorElementExpr>(E->getBase())) ||
+      (BaseTy->isBuiltinType() &&
+       BaseTy->getAs<BuiltinType>()->isSveVLSBuiltinType())) {
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momchil-velikov wrote:

AFAICT here https://github.com/llvm/llvm-project/blob/371eccd5dfed88c8e76449233d8388c12be3464b/clang/lib/Sema/SemaExpr.cpp#L5307 we are enabling array subscripts for SVE only. 

Perhaps we can be generalised to any size-less vector type, in a followup patch, @jacquesguan , what do you think?


https://github.com/llvm/llvm-project/pull/91965