[flang-commits] [flang] [flang] Fix abort on invalid -fdo-concurrent-to-openmp value. (PR #193929)

[Abid Qadeer via flang-commits]

https://github.com/abidh created https://github.com/llvm/llvm-project/pull/193929

We observed that following command can cause an assertion fail
 `flang -fopenmp -fdo-concurrent-to-openmp=devic,e` <file>

It happened because `parseDoConcurrentMapping` reported an error but still called `val.value()` on failure, tripping std::optional assertions.

The fix is to return false on error and wire return into `createFromArgs`.

>From 7f622557fb07c296bee74307cdd744dd866c9a51 Mon Sep 17 00:00:00 2001
From: Abid Qadeer <haqadeer at amd.com>
Date: Fri, 24 Apr 2026 10:36:04 +0100
Subject: [PATCH] [flang] Fix abort on invalid -fdo-concurrent-to-openmp value.

We observed that following command can cause an assertion fail.
flang -fopenmp -fdo-concurrent-to-openmp=devic,e <file>

It happened because parseDoConcurrentMapping reported an error but still called
val.value() on failure, tripping std::optional assertions.

The fix is to return false on error and wire return into createFromArgs.
---
 flang/lib/Frontend/CompilerInvocation.cpp      | 9 +++++----
 flang/test/Driver/do_concurrent_to_omp_cli.f90 | 5 +++++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index fab1b792180c3d..3399616ef8f0b7 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -176,13 +176,13 @@ static bool parseDebugArgs(Fortran::frontend::CodeGenOptions &opts,
   return true;
 }
 
-static void parseDoConcurrentMapping(Fortran::frontend::CodeGenOptions &opts,
+static bool parseDoConcurrentMapping(Fortran::frontend::CodeGenOptions &opts,
                                      llvm::opt::ArgList &args,
                                      clang::DiagnosticsEngine &diags) {
   llvm::opt::Arg *arg =
       args.getLastArg(clang::options::OPT_fdo_concurrent_to_openmp_EQ);
   if (!arg)
-    return;
+    return true;
 
   using DoConcurrentMappingKind =
       Fortran::frontend::CodeGenOptions::DoConcurrentMappingKind;
@@ -197,9 +197,11 @@ static void parseDoConcurrentMapping(Fortran::frontend::CodeGenOptions &opts,
   if (!val.has_value()) {
     diags.Report(clang::diag::err_drv_invalid_value)
         << arg->getAsString(args) << arg->getValue();
+    return false;
   }
 
   opts.setDoConcurrentMapping(val.value());
+  return true;
 }
 
 static bool parseVectorLibArg(Fortran::frontend::CodeGenOptions &opts,
@@ -506,8 +508,6 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
     opts.Underscoring = 0;
   }
 
-  parseDoConcurrentMapping(opts, args, diags);
-
   if (const llvm::opt::Arg *arg =
           args.getLastArg(clang::options::OPT_complex_range_EQ)) {
     llvm::StringRef argValue = llvm::StringRef(arg->getValue());
@@ -1686,6 +1686,7 @@ bool CompilerInvocation::createFromArgs(
   parseTargetArgs(invoc.getTargetOpts(), args);
   parsePreprocessorArgs(invoc.getPreprocessorOpts(), args);
   parseCodeGenArgs(invoc.getCodeGenOpts(), args, diags);
+  success &= parseDoConcurrentMapping(invoc.getCodeGenOpts(), args, diags);
   success &= parseDebugArgs(invoc.getCodeGenOpts(), args, diags);
 
   // Enable USE statement preservation for debug info if debug level is above
diff --git a/flang/test/Driver/do_concurrent_to_omp_cli.f90 b/flang/test/Driver/do_concurrent_to_omp_cli.f90
index e44db04fb2ce7c..723f148d2c3719 100644
--- a/flang/test/Driver/do_concurrent_to_omp_cli.f90
+++ b/flang/test/Driver/do_concurrent_to_omp_cli.f90
@@ -16,5 +16,10 @@
 ! OPT: warning: OpenMP is required for lowering `do concurrent` loops to OpenMP.
 ! OPT-SAME:     Enable OpenMP using `-fopenmp`.
 
+! RUN: not %flang -c -fopenmp -fdo-concurrent-to-openmp=devic,e %s 2>&1 \
+! RUN: | FileCheck %s --check-prefix=BADVAL
+
+! BADVAL: error: invalid value 'devic,e' in '-fdo-concurrent-to-openmp{{.*}}'
+
 program test_cli
 end program