Introduce -fexperimental-loop-fuse to clang and flang (#142686)

This patch adds the flag -fexperimental-loop-fuse to the clang and flang
drivers. This is primarily useful for experiments as we envision to
enable the pass one day.

The options are based on the same principles and reason on which we have
`floop-interchange`.

---------

Co-authored-by: Madhur Amilkanthwar <madhura@nvidia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 76131081..4223752 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1680,6 +1680,9 @@ void CompilerInvocationBase::GenerateCodeGenArgs(const CodeGenOptions &Opts,
   else
     GenerateArg(Consumer, OPT_fno_loop_interchange);
 
+  if (Opts.FuseLoops)
+    GenerateArg(Consumer, OPT_fexperimental_loop_fusion);
+
   if (!Opts.BinutilsVersion.empty())
     GenerateArg(Consumer, OPT_fbinutils_version_EQ, Opts.BinutilsVersion);
 
@@ -2001,6 +2004,8 @@ bool CompilerInvocation::ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
                    (Opts.OptimizationLevel > 1));
   Opts.InterchangeLoops =
       Args.hasFlag(OPT_floop_interchange, OPT_fno_loop_interchange, false);
+  Opts.FuseLoops = Args.hasFlag(OPT_fexperimental_loop_fusion,
+                                OPT_fno_experimental_loop_fusion, false);
   Opts.BinutilsVersion =
       std::string(Args.getLastArgValue(OPT_fbinutils_version_EQ));