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Differential D124861

Correct off-by-one error in the LangRef bitreverse intrinsic semantics
ClosedPublic

Authored by dkreitzer on May 3 2022, 9:46 AM.

Details

Reviewers
RKSimon
spatel
craig.topper
Commits
rG29f70e3e7da8: Minor correction in bitreverse intrinsic semantics
Summary

Should be pretty obvious.

Diff Detail

Unit TestsFailed

TimeTest
60,040 msx64 debian > ThreadSanitizer-x86_64.ThreadSanitizer-x86_64::restore_stack.cpp
60,070 msx64 debian > libFuzzer.libFuzzer::large.test
60,040 msx64 debian > libFuzzer.libFuzzer::value-profile-load.test

Event Timeline

dkreitzer created this revision.May 3 2022, 9:46 AM
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craig.topper accepted this revision.May 3 2022, 9:53 AM
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LGTM

This revision is now accepted and ready to land.May 3 2022, 9:53 AM
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Harbormaster completed remote builds in B162493: Diff 426746.May 3 2022, 11:27 AM
This revision was landed with ongoing or failed builds.May 3 2022, 11:53 AM
Closed by commit rG29f70e3e7da8: Minor correction in bitreverse intrinsic semantics (authored by dkreitzer). · Explain Why
This revision was automatically updated to reflect the committed changes.
dkreitzer added a commit: rG29f70e3e7da8: Minor correction in bitreverse intrinsic semantics.

Revision Contents

PathSize
llvm/
docs/
2 lines

Diff 426746

llvm/docs/LangRef.rst

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The '``llvm.bitreverse``' family of intrinsics is used to reverse the The '``llvm.bitreverse``' family of intrinsics is used to reverse the
bitpattern of an integer value or vector of integer values; for example bitpattern of an integer value or vector of integer values; for example
``0b10110110`` becomes ``0b01101101``. ``0b10110110`` becomes ``0b01101101``.
Semantics: Semantics:
"""""""""" """"""""""
The ``llvm.bitreverse.iN`` intrinsic returns an iN value that has bit The ``llvm.bitreverse.iN`` intrinsic returns an iN value that has bit
``M`` in the input moved to bit ``N-M`` in the output. The vector ``M`` in the input moved to bit ``N-M-1`` in the output. The vector
intrinsics, such as ``llvm.bitreverse.v4i32``, operate on a per-element intrinsics, such as ``llvm.bitreverse.v4i32``, operate on a per-element
basis and the element order is not affected. basis and the element order is not affected.
'``llvm.bswap.*``' Intrinsics '``llvm.bswap.*``' Intrinsics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Syntax: Syntax:
""""""" """""""
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