[PATCH] D116053: [MachineSink] Allow sinking of constant or ignorable physreg uses

[Sebastian Neubauer via Phabricator via llvm-commits]

sebastian-ne added a comment.

This change seems to sink v_cmp instructions, which creates different results if the exec mask changed and that makes several Vulkan tests fail.
I put a reproducer here: https://gist.github.com/Flakebi/fd1d91a806b60ec330e9f61e19fe62ac
Compile with `llc -mtriple=amdgcn--amdpal -mcpu=gfx1010 -verify-machineinstrs -start-before=machine-sink -stop-after=machine-sink PipelineVsFs_0xDD57C231E25DA514.mir -o PipelineVsFs_0xDD57C231E25DA514-after.mir`
and the `%104:sreg_64 = V_CMP_NE_U32_e64 %89, %101, implicit $exec` instruction will be sunk from bb.5 into bb.6. For reference, the pipeline is from the dEQP-VK.subgroups.arithmetic.framebuffer.subgroupexclusiveadd_float_vertex CTS test.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D116053/new/

https://reviews.llvm.org/D116053