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Turn off reloc generation for handles #60721

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jakobbotsch
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@jakobbotsch jakobbotsch commented Oct 21, 2021

Due to #60712 we cannot unconditionally generate lea for handles, since
the runtime does not expect us to ask for reloc hints for
arbitrary constants. In addition, for many Intel CPUs it looks like
rip-relative lea has greater latency than mov with an 8-byte immediate.

Instead of reverting the change I'm just turning it off here, since the
change also unified a couple of functions to simplify the handling.

Fix #60626
Fix #60627
Fix #60629

Due to dotnet#60712 we cannot unconditionally generate lea for handles, since
the runtime does not expect us to generate ask for reloc hints for
arbitrary constants. In addition, for many Intel CPUs it looks like
rip-relative lea has greater latency than mov with an 8-byte immediate.

Instead of reverting the change I'm just turning it off here, since the
change also unified a couple of functions to simplify the handling.

Fix dotnet#60627
Fix dotnet#60626
@dotnet-issue-labeler dotnet-issue-labeler bot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Oct 21, 2021
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ghost commented Oct 21, 2021

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Issue Details

Due to #60712 we cannot unconditionally generate lea for handles, since
the runtime does not expect us to generate ask for reloc hints for
arbitrary constants. In addition, for many Intel CPUs it looks like
rip-relative lea has greater latency than mov with an 8-byte immediate.

Instead of reverting the change I'm just turning it off here, since the
change also unified a couple of functions to simplify the handling.

Fix #60627
Fix #60626

Author: jakobbotsch
Assignees: -
Labels:

area-CodeGen-coreclr

Milestone: -

@jakobbotsch
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cc @dotnet/jit-contrib. ASM diffs are the opposite of #60228 (comment).

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The test failures look to be preexisting.

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LGTM.

@jakobbotsch jakobbotsch merged commit 24864a9 into dotnet:main Oct 22, 2021
@jakobbotsch jakobbotsch deleted the no-reloc-generation-for-handles branch October 22, 2021 16:00
@ghost ghost locked as resolved and limited conversation to collaborators Nov 21, 2021
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