Merge pull request #80919 from 3405691582/amd64

Use LLVM-default spellings for amd64 on OpenBSD.

Author: DougGregor

lib/Basic/Platform.cpp

@@ -291,6 +291,13 @@ StringRef swift::getMajorArchitectureName(const llvm::Triple &Triple) {
       break;
     }
   }
+
+  if (Triple.isOSOpenBSD()) {
+    if (Triple.getArchName() == "amd64") {
+      return "x86_64";
+    }
+  }
+
   return Triple.getArchName();
 }
 
@@ -422,6 +429,11 @@ llvm::Triple swift::getTargetSpecificModuleTriple(const llvm::Triple &triple) {
     return swift::getUnversionedTriple(triple);
   }
 
+  if (triple.isOSOpenBSD()) {
+    StringRef arch = swift::getMajorArchitectureName(triple);
+    return llvm::Triple(arch, triple.getVendorName(), triple.getOSName());
+  }
+
   // Other platforms get no normalization.
   return triple;
 }