Hi! When we compute LABEL_NUSES from scratch, mark_all_labels doesn't call mark_jump_label on DEBUG_INSNs: if (NONDEBUG_INSN_P (insn)) mark_jump_label (PATTERN (insn), insn, 0); and so doesn't increment LABEL_NUSES from references in DEBUG_INSNs. But, when we call emit_copy_of_insn_after e.g. when duplicating some DEBUG_INSNs, we call it even on those, which then results in LABEL_NUSES differences and -fcompare-debug failures.
The following patch makes sure we don't call it on DEBUG_INSNs. Bootstrapped/regtested on powerpc64le-linux, ok for trunk? 2022-04-20 Jakub Jelinek <ja...@redhat.com> PR debug/105203 * emit-rtl.cc (emit_copy_of_insn_after): Don't call mark_jump_label on DEBUG_INSNs. * gfortran.dg/g77/pr105203.f: New test. --- gcc/emit-rtl.cc.jj 2022-02-23 09:17:04.805125253 +0100 +++ gcc/emit-rtl.cc 2022-04-20 10:26:44.972198107 +0200 @@ -6440,7 +6440,8 @@ emit_copy_of_insn_after (rtx_insn *insn, } /* Update LABEL_NUSES. */ - mark_jump_label (PATTERN (new_rtx), new_rtx, 0); + if (NONDEBUG_INSN_P (insn)) + mark_jump_label (PATTERN (new_rtx), new_rtx, 0); INSN_LOCATION (new_rtx) = INSN_LOCATION (insn); --- gcc/testsuite/gfortran.dg/g77/pr105203.f.jj 2022-04-20 10:29:44.830696254 +0200 +++ gcc/testsuite/gfortran.dg/g77/pr105203.f 2022-04-20 10:31:13.532463772 +0200 @@ -0,0 +1,20 @@ +C Test case for PR debug/105203 +C Origin: kmcca...@princeton.edu +C +C { dg-do compile } +C { dg-options "-O2 -fcompare-debug -ftracer -w" } +C { dg-additional-options "-fPIC" { target fpic } } + SUBROUTINE FOO (B) + + 10 CALL BAR (A) + ASSIGN 20 TO M + IF (100.LT.A) GOTO 10 + GOTO 40 +C + 20 IF (B.LT.ABS(A)) GOTO 10 + ASSIGN 30 TO M + GOTO 40 +C + 30 ASSIGN 10 TO M + 40 GOTO M,(10,20,30) + END Jakub