[New-bugs-announce] [issue28117] warning: dereferencing type-punned pointer will break strict-aliasing rules

[Serhiy Storchaka]

New submission from Serhiy Storchaka:

In file included from /home/serhiy/py/cpython/Modules/_sha3/sha3module.c:113:0:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c: In function ‘_PySHA3_KeccakP1600_SetBytesInLaneToZero’:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c:97:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
     low = *((UINT32*)(laneAsBytes+0));
     ^
In file included from /home/serhiy/py/cpython/Modules/_sha3/sha3module.c:113:0:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c: In function ‘_PySHA3_KeccakP1600_AddBytesInLane’:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c:152:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
     low = *((UINT32*)(laneAsBytes+0));
     ^
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c: In function ‘_PySHA3_KeccakP1600_ExtractBytesInLane’:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c:296:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
     *((UINT32*)(laneAsBytes+0)) = low;
     ^
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c: In function ‘_PySHA3_KeccakP1600_ExtractAndAddBytesInLane’:
/home/serhiy/py/cpython/Modules/_sha3/kcp/KeccakP-1600-inplace32BI.c:369:5: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
     *((UINT32*)(laneAsBytes+0)) = low;
     ^

----------
components: Extension Modules
messages: 276193
nosy: christian.heimes, mark.dickinson, serhiy.storchaka
priority: normal
severity: normal
status: open
title: warning: dereferencing type-punned pointer will break strict-aliasing rules
type: compile error
versions: Python 3.6, Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue28117>
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