[flang] add -floop-interchange and enable it with opt levels (#140182)

Enable the use of -floop-interchange from the flang driver.
Enable in flang LLVM's loop interchange at levels -O2, -O3, -Ofast, and -Os.

2 files changed, 4 insertions, 0 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index b6c3771..ba25318 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -270,6 +270,9 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
                    clang::driver::options::OPT_fno_stack_arrays, false))
     opts.StackArrays = 1;
 
+  if (args.getLastArg(clang::driver::options::OPT_floop_interchange))
+    opts.InterchangeLoops = 1;
+
   if (args.getLastArg(clang::driver::options::OPT_vectorize_loops))
     opts.VectorizeLoop = 1;
 
diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp
index e5a15c5..38dfaad 100644
--- a/flang/lib/Frontend/FrontendActions.cpp
+++ b/flang/lib/Frontend/FrontendActions.cpp
@@ -922,6 +922,7 @@ void CodeGenAction::runOptimizationPipeline(llvm::raw_pwrite_stream &os) {
   if (ci.isTimingEnabled())
     si.getTimePasses().setOutStream(ci.getTimingStreamLLVM());
   pto.LoopUnrolling = opts.UnrollLoops;
+  pto.LoopInterchange = opts.InterchangeLoops;
   pto.LoopInterleaving = opts.UnrollLoops;
   pto.LoopVectorization = opts.VectorizeLoop;
   pto.SLPVectorization = opts.VectorizeSLP;