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From: "dimhen at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/102386] New: [12 regression] bogus -Wrestrict for unreachable memcpy() Date: Fri, 17 Sep 2021 10:43:55 +0000 [thread overview] Message-ID: <bug-102386-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102386 Bug ID: 102386 Summary: [12 regression] bogus -Wrestrict for unreachable memcpy() Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: dimhen at gmail dot com Target Milestone: --- r12-3456 PASS r12-3545 FAIL $ cat x.i static int GetHashParam_HP_OPAQUEBLOB_pdwDataLen = 0; void *memcpy(void *, const void *, unsigned long); typedef struct { int tSimpleBlobHeader; int bCurrKey[]; } CRYPT_OPAQUEHASHBLOB; int GetHashParam_HP_OPAQUEBLOB() { CRYPT_OPAQUEHASHBLOB *pBlb; if (GetHashParam_HP_OPAQUEBLOB_pdwDataLen) { void *pcn = pBlb->bCurrKey, *pdwBuff = pBlb->bCurrKey; int dwDWBufLen = 8; memcpy(pcn, pdwBuff, sizeof(1) * dwDWBufLen); } return 1; } $ gcc -fpreprocessed -O --param max-early-inliner-iterations=2 -Wrestrict -c x.i x.i: In function 'GetHashParam_HP_OPAQUEBLOB': x.i:12:5: warning: 'memcpy' accessing 32 bytes at offsets 4 and 4 overlaps 32 bytes at offset 4 [-Wrestrict] 12 | memcpy(pcn, pdwBuff, sizeof(1) * dwDWBufLen); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Test extracted from private codebase. Key part: static inline void foo(void *p, void *q, int N) { if(p != q) memcpy(p, q, N); } void bar(void q, void p, int N) { foo(p, q, N); }
next reply other threads:[~2021-09-17 10:43 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-17 10:43 dimhen at gmail dot com [this message] 2021-09-18 22:48 ` [Bug middle-end/102386] " msebor at gcc dot gnu.org
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