https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83761
--- Comment #4 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Thu Jan 11 09:54:26 2018 New Revision: 256525 URL: https://gcc.gnu.org/viewcvs?rev=256525&root=gcc&view=rev Log: Fix mode_for_size units in caller-save.c (PR83761) The new opt_mode asserts triggered for replace_reg_with_saved_mem because it was passing bytes rather than bits to mode_for_size. Previously we ended up with a BLKmode register instead, but presumably that didn't matter because this is "only" used for debug insns. 2018-01-11 Richard Sandiford <richard.sandif...@linaro.org> gcc/ PR rtl-optimization/83761 * caller-save.c (replace_reg_with_saved_mem): Pass bits rather than bytes to mode_for_size. Modified: trunk/gcc/ChangeLog trunk/gcc/caller-save.c