[all-commits] [llvm/llvm-project] b200c5: Reland [MachineCopyPropagation] Extend MCP to do t...

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  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: b200c5180e8d6f9ac4e08512a04739ab02cebdb8
      https://github.com/llvm/llvm-project/commit/b200c5180e8d6f9ac4e08512a04739ab02cebdb8
  Author: Kai Luo <lkail at cn.ibm.com>
  Date:   2019-12-05 (Thu, 05 Dec 2019)

  Changed paths:
    M llvm/lib/CodeGen/MachineCopyPropagation.cpp
    M llvm/test/CodeGen/PowerPC/machine-backward-cp.mir
    M llvm/test/CodeGen/PowerPC/redundant-copy-after-tail-dup.ll
    M llvm/test/CodeGen/RISCV/alu64.ll
    M llvm/test/CodeGen/RISCV/shifts.ll
    M llvm/test/CodeGen/X86/fp128-i128.ll
    M llvm/test/CodeGen/X86/fshr.ll
    M llvm/test/CodeGen/X86/i128-mul.ll
    M llvm/test/CodeGen/X86/mul-i512.ll
    M llvm/test/CodeGen/X86/shift-i128.ll
    M llvm/test/CodeGen/X86/umulo-128-legalisation-lowering.ll

  Log Message:
  -----------
  Reland [MachineCopyPropagation] Extend MCP to do trivial copy backward propagation.

Fix assertion error
```
bool llvm::MachineOperand::isRenamable() const: Assertion `Register::isPhysicalRegister(getReg()) && "isRenamable should only be checked on physical registers"' failed.
```
by checking if the register is 0 before invoking `isRenamable`.