[clang] First draft: [Clang] Add constant evaluation support for x86 psadbw (PR #169253)

[Simon Pilgrim via cfe-commits]

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@@ -0,0 +1,64 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -O0 \
+// RUN:   -fexperimental-new-constant-interpreter -verify %s
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -O0 \
+// RUN:   -target-feature +avx2 -target-feature +avx512bw \
+// RUN:   -fexperimental-new-constant-interpreter -verify %s
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RKSimon wrote:

delete this and just use the TEST_CONSTEXPR macros in the builtins-* codegen files

https://github.com/llvm/llvm-project/pull/169253