[clang] [clang][CodeGen][MSVC] Return vector types from methods indirectly (PR #157365)

[Henry Baba-Weiss via cfe-commits]

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@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -ffreestanding -emit-llvm %s -o - -triple=i686-pc-windows-msvc \
+// RUN:   | FileCheck %s
+// RUN: %clang_cc1 -ffreestanding -emit-llvm %s -o - -triple=x86_64-pc-windows-msvc \
+// RUN:   | FileCheck %s
+// RUN: %clang_cc1 -ffreestanding -emit-llvm %s -o - -triple=i686-pc-windows-msvc \
+// RUN:   -fclang-abi-compat=21 | FileCheck --check-prefixes=CLANG21 %s
+// RUN: %clang_cc1 -ffreestanding -emit-llvm %s -o - -triple=x86_64-pc-windows-msvc \
+// RUN:   -fclang-abi-compat=21 | FileCheck --check-prefixes=CLANG21 %s
+
+// To match the MSVC ABI, vector types must be returned indirectly from member
+// functions (as long as they do not use the vectorcall calling convention),
+// but must be returned directly everywhere else.
+
+#include <xmmintrin.h>
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henrybw wrote:

Done. (I was also surprised by MSVC returning vectors directly on ARM64, but that's also why I constrained this behavior to only apply to x86/x86-64 targets.)

https://github.com/llvm/llvm-project/pull/157365