[clang] [clang][PowerPC] Add flag to enable compatibility with GNU for complex arguments (PR #77732)

[zhijian lin via cfe-commits]

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+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 2
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+// RUN: %clang_cc1 -triple powerpc-unknown-linux-gnu -target-cpu pwr8 \
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diggerlin wrote:

do you really need `-target-cpu pwr8` since the test case only check generated IR?

https://github.com/llvm/llvm-project/pull/77732