On Fri, Apr 05, 2019 at 09:25:08PM -0500, William Tambe wrote: > What is the reason that GCC does not always automatically include the > frame-pointer and return-address registers in df_regs_ever_live_p such > that it is necessary to check respectively frame_pointer_needed and > crtl->profile ? ie: > https://github.com/gcc-mirror/gcc/blob/gcc-8_3_0-release/gcc/config/fr30/fr30.c#L145 The code that actually sets up the frame pointer or return address is not yet necessarily part of the rtl stream where these checks are used. The prologue code is inserted in the pro_and_epilogue pass, which runs a bit _after_ reload (or LRA, in the more modern world). So DF does not see those insns yet, because they simply do not exist yet ;-) The target can make sure the entry block defines these regs, but it sounds like fr30 did not do that. Segher
