https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113220
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Richard Sandiford <rsand...@gcc.gnu.org>: https://gcc.gnu.org/g:4f7d4a2cd26673887f45e994a2f367a5c8fcc691 commit r14-9097-g4f7d4a2cd26673887f45e994a2f367a5c8fcc691 Author: Richard Sandiford <richard.sandif...@arm.com> Date: Wed Feb 21 11:12:26 2024 +0000 Allow mode-switching to introduce internal loops [PR113220] In this PR, the SME mode-switching code needs to insert a stack-probe loop for an alloca. This patch allows the target to do that. There are two parts to it: allowing loops for insertions in blocks, and allowing them for insertions on edges. The former can be handled entirely within mode-switching itself, by recording which blocks have had new branches inserted. The latter requires an extension to commit_one_edge_insertion. I think the extension to commit_one_edge_insertion makes logical sense, since it already explicitly allows internal loops during RTL expansion. The single-block find_sub_basic_blocks is a relatively recent addition, so wouldn't have been available when the code was originally written. The patch also has a small and obvious fix to make the aarch64 emit hook cope with labels. I've added specific -fstack-clash-protection versions of all aarch64-sme.exp tests that previously failed because of this bug. I've also added -fno-stack-clash-protection to the original versions of these tests if they contain scans that assume no protection. gcc/ PR target/113220 * cfgrtl.cc (commit_one_edge_insertion): Handle sequences that contain jumps even if called after initial RTL expansion. * mode-switching.cc: Include cfgbuild.h. (optimize_mode_switching): Allow the sequence returned by the emit hook to contain internal jumps. Record which blocks contain such jumps and split the blocks at the end. * config/aarch64/aarch64.cc (aarch64_mode_emit): Check for non-debug insns when scanning the sequence. gcc/testsuite/ PR target/113220 * gcc.target/aarch64/sme/call_sm_switch_5.c: Add -fno-stack-clash-protection. * gcc.target/aarch64/sme/call_sm_switch_5_scp.c: New test. * gcc.target/aarch64/sme/sibcall_6_scp.c: New test. * gcc.target/aarch64/sme/za_state_4.c: Add -fno-stack-clash-protection. * gcc.target/aarch64/sme/za_state_4_scp.c: New test. * gcc.target/aarch64/sme/za_state_5.c: Add -fno-stack-clash-protection. * gcc.target/aarch64/sme/za_state_5_scp.c: New test.
