[PATCH] Improve DAG combine pass on certain IR vector patterns

Quentin Colombet qcolombet at apple.com
Fri Jan 16 11:59:11 PST 2015

Hi Fiona,

The approach looks overall good to me, but I have a few remarks and questions.
1. Run your patch through clang-format please. The patch does not follow the LLVM formatting guidelines.
2. What is the impact of this on arm64 and armv7s generated code? Although the approach makes sense to me, I want to be sure we do not degrade other targets. Note that I do not expect you to run tests if you cannot :).
3. What are the runtime performance impact on x86_64, with and without -mavx2?
4. Add a run line for avx  too:
+; RUN: llc < %s -march=x86-64 -mattr=+avx2 | FileCheck %s
5. Should we use a triple instead of march?


On Jan 16, 2015, at 11:24 AM, Fiona Glaser <fglaser at apple.com> wrote:

> Talked about this one offline and decided to implement Mehdi’s strategy.
> Fiona
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