https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88598
--- Comment #9 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Mon Jan 7 12:17:10 2019 New Revision: 267646 URL: https://gcc.gnu.org/viewcvs?rev=267646&root=gcc&view=rev Log: [2/2] PR88598: Optimise reduc (bit_and) This patch folds certain reductions of X & CST to X[I] & CST[I] if I is the only nonzero element of CST. This includes the motivating case in which CST[I] is -1. We could do the same for REDUC_MAX on unsigned types, but I wasn't sure that that special case was worth it. 2019-01-07 Richard Sandiford <richard.sandif...@arm.com> gcc/ PR tree-optimization/88598 * tree.h (single_nonzero_element): Declare. * tree.c (single_nonzero_element): New function. * match.pd: Fold certain reductions of X & CST to X[I] & CST[I] if I is the only nonzero element of CST. gcc/testsuite/ PR tree-optimization/88598 * gcc.dg/vect/pr88598-1.c: New test. * gcc.dg/vect/pr88598-2.c: Likewise. * gcc.dg/vect/pr88598-3.c: Likewise. * gcc.dg/vect/pr88598-4.c: Likewise. * gcc.dg/vect/pr88598-5.c: Likewise. * gcc.dg/vect/pr88598-6.c: Likewise. Added: trunk/gcc/testsuite/gcc.dg/vect/pr88598-1.c trunk/gcc/testsuite/gcc.dg/vect/pr88598-2.c trunk/gcc/testsuite/gcc.dg/vect/pr88598-3.c trunk/gcc/testsuite/gcc.dg/vect/pr88598-4.c trunk/gcc/testsuite/gcc.dg/vect/pr88598-5.c trunk/gcc/testsuite/gcc.dg/vect/pr88598-6.c Modified: trunk/gcc/ChangeLog trunk/gcc/match.pd trunk/gcc/testsuite/ChangeLog trunk/gcc/tree.c trunk/gcc/tree.h
