https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67800
Bug ID: 67800 Summary: [6 Regression] Missed vectorization opportunity on x86 Product: gcc Version: 6.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: afomin.mailbox at gmail dot com CC: izamyatin at gmail dot com, rguenth at gcc dot gnu.org, ysrumyan at gmail dot com Target Milestone: --- Target: i686-*-* Created attachment 36434 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36434&action=edit A reproducer A loop in the test attached compiled with -m32 -msse4.2 -O2 -ftree-vectorize -fPIE -pie -c is no more vectorized after r223525 (while on r223524 everything is OK) because of strange DOT_PROD_EXPR recognition (see below). vect_is_simple_use: operand _15 def_stmt: _15 = _14 * 76; type of def: internal vect_recog_dot_prod_pattern: detected: patt_47 = DOT_PROD_EXPR <_2, 76, _17>; pattern recognized: patt_47 = DOT_PROD_EXPR <_2, 76, _17>;