[PATCH] D133929: [DebugInfo] Produce variadic DBG_INSTR_REFs from ISel

[Stephen Tozer via Phabricator via llvm-commits]

StephenTozer added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp:921
+  }
+  return &*MIB;
+}
----------------
Orlando wrote:
> Is there a benefit to preserving the number of operands (rather than just using `DBG_VALUE $noreg`) - does it strip assertions about DW_OP_arg usage or something if we don't?
The only important part about this is that it doesn't invalidate the DIExpression - even for an undef debug value, I believe there are still some points at which having a mismatched number of debug operands with the DIExpression's arg operands is a problem. This could be resolved by also changing the expression, making it empty while any fragment info or other expression elements that apply to undef values - which sounds like something that should be done for all explicitly killed debug values, but happy to start the ball rolling here.


Repository:
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  https://reviews.llvm.org/D133929/new/

https://reviews.llvm.org/D133929