The narrow_gp_writes pass uses RTL-SSA and updates DF state via df_insn_rescan / df_insn_delete. Both routines look up the insn's bb via BLOCK_FOR_INSN to mark it dirty after a change, but pass_free_cfg has already cleared those per-insn pointers by the time narrow_gp_writes runs. When BLOCK_FOR_INSN returns NULL, the dirty-marking step is silently skipped, leaving the DF stale.
Move the pass to run before pass_free_cfg. Bootstrapped and regtested on aarch64-linux-gnu. SPEC CPU 2017 shows no codegen differences (compared to previous placement). OK for trunk? Signed-off-by: Soumya AR <[email protected]> PR target/124895 gcc/ChangeLog: * config/aarch64/aarch64-passes.def (INSERT_PASS_BEFORE): Move pass before pass_free_cfg. gcc/testsuite/ChangeLog: * gcc.target/aarch64/narrow-gp-writes-8.c: New test. --- gcc/config/aarch64/aarch64-passes.def | 2 +- gcc/testsuite/gcc.target/aarch64/narrow-gp-writes-8.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.target/aarch64/narrow-gp-writes-8.c diff --git a/gcc/config/aarch64/aarch64-passes.def b/gcc/config/aarch64/aarch64-passes.def index f4307aab551..2df7459af92 100644 --- a/gcc/config/aarch64/aarch64-passes.def +++ b/gcc/config/aarch64/aarch64-passes.def @@ -26,4 +26,4 @@ INSERT_PASS_BEFORE (pass_late_thread_prologue_and_epilogue, 1, pass_late_track_s INSERT_PASS_BEFORE (pass_shorten_branches, 1, pass_insert_bti); INSERT_PASS_BEFORE (pass_early_remat, 1, pass_ldp_fusion); INSERT_PASS_BEFORE (pass_peephole2, 1, pass_ldp_fusion); -INSERT_PASS_BEFORE (pass_cleanup_barriers, 1, pass_narrow_gp_writes); +INSERT_PASS_BEFORE (pass_free_cfg, 1, pass_narrow_gp_writes); diff --git a/gcc/testsuite/gcc.target/aarch64/narrow-gp-writes-8.c b/gcc/testsuite/gcc.target/aarch64/narrow-gp-writes-8.c new file mode 100644 index 00000000000..94ef761e801 --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/narrow-gp-writes-8.c @@ -0,0 +1,10 @@ +/* PR target/124895 */ +/* { dg-do compile } */ +/* { dg-options "-Os -fpath-coverage -fno-tree-ccp -fprofile-generate -mnarrow-gp-writes" } */ + +void +foo (unsigned u) +{ + while (u) + ; +} -- 2.43.0
