[Flang] Add __powerpc__ macro to set c_intmax_t to c_int64_t rather than c_int128_t as PowerPC only supports up to c_int64_t. (#81222)

PowerPC only supports up to `c_int64_t`. Add macro `__powerpc__` and
preprocess it for setting `c_intmax_t` in `iso_c_binding` intrinsic
module.

1 files changed, 14 insertions, 1 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index ffde7f5..4707de0 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1326,10 +1326,23 @@ void CompilerInvocation::setDefaultPredefinitions() {
     Fortran::common::setOpenMPMacro(getLangOpts().OpenMPVersion,
                                     fortranOptions.predefinitions);
   }
+
   llvm::Triple targetTriple{llvm::Triple(this->targetOpts.triple)};
-  if (targetTriple.getArch() == llvm::Triple::ArchType::x86_64) {
+  switch (targetTriple.getArch()) {
+  default:
+    break;
+  case llvm::Triple::ArchType::x86_64:
     fortranOptions.predefinitions.emplace_back("__x86_64__", "1");
     fortranOptions.predefinitions.emplace_back("__x86_64", "1");
+    break;
+  case llvm::Triple::ArchType::ppc:
+  case llvm::Triple::ArchType::ppcle:
+  case llvm::Triple::ArchType::ppc64:
+  case llvm::Triple::ArchType::ppc64le:
+    // '__powerpc__' is a generic macro for any PowerPC cases. e.g. Max integer
+    // size.
+    fortranOptions.predefinitions.emplace_back("__powerpc__", "1");
+    break;
   }
 }