[clang] [Clang][RISCV] Add operator overloading for builtin RVV vector types (PR #192722)

[David Truby via cfe-commits]

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@@ -0,0 +1,99 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py
+// RUN: %clang_cc1 -triple riscv32 -target-feature +v \
+// RUN: -disable-O0-optnone \
+// RUN:  -emit-llvm -o - %s | opt -S -passes=sroa | FileCheck %s \
+// RUN:  --check-prefixes=CHECK,CHECK32
+// RUN: %clang_cc1 -triple riscv64 -target-feature +v \
+// RUN: -disable-O0-optnone \
+// RUN:  -emit-llvm -o - %s | opt -S -passes=sroa | FileCheck %s \
+// RUN:  --check-prefixes=CHECK,CHECK64
+
+// REQUIRES: riscv-registered-target
+
+#include <riscv_vector.h>
+#include <stddef.h>
+
+// CONSTANT INDEX
+
+// CHECK-LABEL: @subscript_const_i32(
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[VECEXT:%.*]] = extractelement <vscale x 2 x i32> [[A:%.*]], i32 0
+// CHECK-NEXT:    ret i32 [[VECEXT]]
+//
+int subscript_const_i32(vint32m1_t a) {
+  return a[0];
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DavidTruby wrote:

For the subscripts, you're missing a necessary change in [CGExprScalar.cpp](https://github.com/llvm/llvm-project/blob/9830c433751d9d998f739d74b12a9a5a22928542/clang/lib/CodeGen/CGExprScalar.cpp#L2204) that would allow rvalues to be subscritped (e.g. `(a+b)[0]`). That condition should probably be `!E->getBase()->getType()->isSubscriptableVectorType()` (and probably should have been before anyway).

https://github.com/llvm/llvm-project/pull/192722