[clang] [llvm] [PowerPC][clang] Fix triple constructor ambiguity causing "unknown" target triple on AIX (PR #147488)

[Hubert Tong via llvm-commits]

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@@ -55,7 +55,7 @@ static std::string updateTripleOSVersion(std::string TargetTripleString) {
   // On AIX, the AIX version and release should be that of the current host
   // unless if the version has already been specified.
   if (Triple(LLVM_HOST_TRIPLE).getOS() == Triple::AIX) {
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hubert-reinterpretcast wrote:

> This function shouldn't depend on the host triple in the first place

This function intends to transfer host characteristics (the OS version information) to AIX target triples (which is then used in Clang for predefined macros, among other things). The host characteristics have no reasonable relation to the AIX target triple unless the compiler is hosted on AIX.

https://github.com/llvm/llvm-project/pull/147488