https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94043
--- Comment #23 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Kewen Lin <li...@gcc.gnu.org>: https://gcc.gnu.org/g:a809efd70d18c079d41051dc408de5e5f86a9797 commit r9-8506-ga809efd70d18c079d41051dc408de5e5f86a9797 Author: Kewen Lin <li...@linux.ibm.com> Date: Tue Mar 31 22:48:46 2020 -0500 Fix PR94043 by making vect_live_op generate lc-phi As PR94043 shows, my commit r10-4524 exposed one issue in vectorizable_live_operation, which inserts one extra BB before the single exit, leading unexpected operand expansion and unexpected loop depth assertion. As Richi suggested, this patch is to teach vectorizable_live_operation to generate loop closed phi for vec_lhs, it looks like: loop; # lhs' = PHI <lhs> => loop; # vec_lhs' = PHI <vec_lhs> new_tree = BIT_FIELD_REF <vec_lhs', ...>; lhs' = new_tree; I noticed that there are some SLP cases that have same lhs and vec_lhs but different offsets, which can make us have more PHIs for the same vec_lhs there. But I think it would be fine since only one of them is actually live, the others should be eliminated by the following dce. So the patch doesn't check whether there is one phi for vec_lhs, just create one directly instead. Bootstrapped/regtested on powerpc64le-linux-gnu (LE) P8. Backport from mainline. 2020-04-01 Kewen Lin <li...@gcc.gnu.org> gcc/ChangeLog PR tree-optimization/94043 * tree-vect-loop.c (vectorizable_live_operation): Generate loop-closed phi for vec_lhs and use it for lane extraction. gcc/testsuite/ChangeLog PR tree-optimization/94043 * gfortran.dg/graphite/vect-pr94043.f90: New test.
