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

[Tarun Prabhu via cfe-commits]

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@@ -52,6 +52,15 @@
 // CHECK-INTERCHANGE-LOOPS: "-floop-interchange"
 // CHECK-NO-INTERCHANGE-LOOPS: "-fno-loop-interchange"
 
+// RUN: %clang -### -S -fexperimental-loop-fusion %s 2>&1 | FileCheck -check-prefix=CHECK-FUSE-LOOPS %s
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tarunprabhu wrote:

I was partly basing this on the fact that the loop-interchange above does check for both, but if I have not checked if that uses `addOptInFlag`. If there is precedence for not testing it, that's fine too.

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