[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.

[DanielCChen]

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.

[llvmbot]

@llvm/pr-subscribers-flang-driver

Author: Daniel Chen (DanielCChen)

Changes

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.

---

Full diff: https://github.com/llvm/llvm-project/pull/81222.diff

2 Files Affected:

• (modified) flang/lib/Frontend/CompilerInvocation.cpp (+12-1)
• (modified) flang/module/iso_c_binding.f90 (+4)

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index ffde7f50087e52..d49e8e283e0d40 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1326,10 +1326,21 @@ 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:
+    fortranOptions.predefinitions.emplace_back("__powerpc__", "1");
+    break;
   }
 }
 
diff --git a/flang/module/iso_c_binding.f90 b/flang/module/iso_c_binding.f90
index 9a7e68f3314463..1661fd5a6dcf6a 100644
--- a/flang/module/iso_c_binding.f90
+++ b/flang/module/iso_c_binding.f90
@@ -47,7 +47,11 @@ module iso_c_binding
     c_long_long = c_int64_t, &
     c_signed_char = c_int8_t, &
     c_size_t = kind(c_sizeof(1)), &
+#if __powerpc__
+    c_intmax_t = c_int64_t, &
+#else
     c_intmax_t = c_int128_t, &
+#endif
     c_intptr_t = c_size_t, &
     c_ptrdiff_t = c_size_t
   integer, parameter, public :: &

[DanielCChen]

The x86 build failure seems on and off to me. This PR passed the x86 build before I rebased the branch.

[kkwli]

Need to add a test like test/Driver/predefined-macros-x86.f90.

[kkwli]

LGTM

Thanks