[llvm-dev] Understanding and Cleaning Up Machine Instruction Bundles

Matthias Braun via llvm-dev llvm-dev at lists.llvm.org
Thu Oct 27 17:54:09 PDT 2016

> On Oct 27, 2016, at 5:45 PM, Krzysztof Parzyszek <kparzysz at codeaurora.org> wrote:
> On 10/27/2016 7:34 PM, Matthias Braun wrote:
>> Just to clarify: No matter the proposal/style the whole bundle is considered a single instruction in terms of liveness / identifying a position in the program. We would not make any assumptions about how the bundle is executed/behaves internally.
>> The iterator over all operands inside the bundle would just as well give you the union of all defs and use operands inside the bundle (ignoring internal read of course) in a similar fashion to the operands you have on the BUNDLE instruction today.
> Would the operands be traversed in any specific order?
Nobody will make assumptions based on the order, that must be true for single instructions today already and would not change. Semantically first all the (non-internal) uses happen then all the defs happen.

- Matthias

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