https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80802
Bug ID: 80802 Summary: [7/8 Regression] VRP triggers (causes) a miscompile in icu4c 58.2 Product: gcc Version: 7.1.0 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target Milestone: --- Target: i?86-*-* Created attachment 41374 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41374&action=edit unreduced testcase On i586 icu4c is miscompiled by GCC 7 (but not GCC 6). We've sofar narrowed it down to icu/source/i18n/precision.cpp function FixedPrecision::initVisibleDigits double overload (preprocessed source attached, function already marked with optimize attribute). Disabling VRP1 "fixes" the issue but VRP1 does lots of threading and thus might just uncover an issue elsewhere. invalid source not yet ruled out completely.