[all-commits] [llvm/llvm-project] 23fbe5: [flang] do not merge block after lowering

[jeanPerier via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 23fbe525ce0645341610b751184882fea264c99e
      https://github.com/llvm/llvm-project/commit/23fbe525ce0645341610b751184882fea264c99e
  Author: Jean Perier <jperier at nvidia.com>
  Date:   2023-06-28 (Wed, 28 Jun 2023)

  Changed paths:
    M flang/lib/Lower/Bridge.cpp
    A flang/test/Lower/HLFIR/no-block-merging.f90
    M flang/test/Lower/block.f90
    M flang/test/Lower/entry-statement.f90

  Log Message:
  -----------
  [flang] do not merge block after lowering

Lowering relies on dead code generation / unreachable block deletion
to delete some code that is potentially invalid.

However, calling mlir::simplifyRegion also merges block, which may
promote SSA values to block arguments. Not all FIR types are intended
to be block arguments.
The added test shows an example where block merging led to
fir.shape<> being block arguments (and a failure later in codegen).

Reviewed By: tblah, clementval, vdonaldson

Differential Revision: https://reviews.llvm.org/D153858