[all-commits] [llvm/llvm-project] 0b2f4c: Explicitly check for entry basic block, rather tha...

[Rahman Lavaee via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 0b2f4cdf2bd4e48974099cd441afaabc18ead227
      https://github.com/llvm/llvm-project/commit/0b2f4cdf2bd4e48974099cd441afaabc18ead227
  Author: Rahman Lavaee <rahmanl at google.com>
  Date:   2020-10-26 (Mon, 26 Oct 2020)

  Changed paths:
    M llvm/include/llvm/CodeGen/AsmPrinter.h
    M llvm/include/llvm/CodeGen/MachineBasicBlock.h
    M llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    M llvm/lib/CodeGen/MachineBasicBlock.cpp
    A llvm/test/CodeGen/X86/basic-block-sections-unreachable.ll

  Log Message:
  -----------
  Explicitly check for entry basic block, rather than relying on MachineBasicBlock::pred_empty.

Sometimes in unoptimized code, we have dangling unreachable basic blocks with no predecessors. Basic block sections should be emitted for those as well. Without this patch, the included test fails with a fatal error in `AsmPrinter::emitBasicBlockEnd`.

Reviewed By: tmsriram

Differential Revision: https://reviews.llvm.org/D89423