[llvm] Add missed Darwin/i386 for `withHostArch` (PR #67617)

[Kirill A. Korinsky via llvm-commits]

https://github.com/catap created https://github.com/llvm/llvm-project/pull/67617

This regression was introduced at LLVM-17 via dc078e6eaacff66596fac76b6104aa504f77d45d

>From 45b5213c1344b7f8dc49e3f538dcae8c7f0d256d Mon Sep 17 00:00:00 2001
From: "Kirill A. Korinsky" <kirill at korins.ky>
Date: Thu, 28 Sep 2023 00:43:02 +0200
Subject: [PATCH] Add missed Darwin/i386 for `withHostArch`

This regression was introduced at LLVM-17 via dc078e6eaacff66596fac76b6104aa504f77d45d
---
 llvm/lib/TargetParser/Host.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/llvm/lib/TargetParser/Host.cpp b/llvm/lib/TargetParser/Host.cpp
index 1c4feff26d98488..0fd95b2a65bca7d 100644
--- a/llvm/lib/TargetParser/Host.cpp
+++ b/llvm/lib/TargetParser/Host.cpp
@@ -1930,6 +1930,9 @@ static Triple withHostArch(Triple T) {
 #elif defined(__x86_64__)
   T.setArch(Triple::x86_64);
   T.setArchName("x86_64");
+#elif defined(__i386__)
+  T.setArch(Triple::x86);
+  T.setArchName("i386");
 #elif defined(__powerpc__)
   T.setArch(Triple::ppc);
   T.setArchName("powerpc");