[flang-commits] [flang] [Flang]Add support for inlining hlfir.assign operation where both LHS and RHS are slices of the same array (PR #204532)

[Eugene Epshteyn via flang-commits]

eugeneepshteyn wrote:

@kaviya2510 , unfortunately this change causes regressions in several important apps. The issue could be reproduced with this Fujitsu test: https://github.com/fujitsu/compiler-test-suite/blob/main/Fortran/0073/0073_0009.f90

Reproduction:
```
$ flang -c -fopenmp -O1 0073_0009.f90 
loc(".../0073_0009.f90":18:3): error: failed to legalize operation 'hlfir.as_expr' that was explicitly marked illegal: %261 = "hlfir.as_expr"(%199) : (!fir.box<!fir.heap<!fir.array<10x100xi32>>>) -> !hlfir.expr<10x100xi32>
error: failure in HLFIR to FIR conversion pass
error: Lowering to LLVM IR failed
loc(".../0073_0009.f90":11:1): error: cannot be converted to LLVM IR: missing `LLVMTranslationDialectInterface` registration for dialect for op: func.func
error: failed to create the LLVM module
```

Unless a quick fix is possible, I will have to revert this change and you can re-land it later with the fix applied.

https://github.com/llvm/llvm-project/pull/204532