https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79449
Bug ID: 79449
Summary: ppc builtin expansion of strncmp can cross page (4k)
boundary where it should not
Product: gcc
Version: 7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: acsawdey at gcc dot gnu.org
Reporter: acsawdey at gcc dot gnu.org
CC: segher at gcc dot gnu.org, wschmidt at gcc dot gnu.org
Target Milestone: ---
Target: powerpc64*-*-*
When one of the string args to strncmp has alignment of less than 8 bytes, the
builtin expansion code generates a runtime check to see if the string might
cross a 4k boundary. However the runtime check looks for at least the length N
before the next 4k boundary and then the code generated may load a doubleword,
crossing the 4k boundary if N is less than 8.
