[clang] [flang] [llvm] Introduce -fexperimental-loop-fuse to clang and flang (PR #142686)

[Fangrui Song via llvm-commits]

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@@ -6870,6 +6870,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                   options::OPT_fno_unroll_loops);
   Args.AddLastArg(CmdArgs, options::OPT_floop_interchange,
                   options::OPT_fno_loop_interchange);
+  Args.AddLastArg(CmdArgs, options::OPT_fexperimental_loop_fusion,
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MaskRay wrote:

addOptInFlag to ensure the negative option does not get forwarded to cc1

https://github.com/llvm/llvm-project/pull/142686