emit-rtl: Fix -fcompare-debug bug with label references in debug insns [PR105203]

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.

2022-04-21  Jakub Jelinek  <jakub@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.

diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
index f4404d7..1e02ae2 100644 (file)
--- a/gcc/emit-rtl.cc
+++ b/gcc/emit-rtl.cc
@@ -6440,7 +6440,8 @@ emit_copy_of_insn_after (rtx_insn *insn, rtx_insn *after)
     }
 
   /* 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);
 

diff --git a/gcc/testsuite/gfortran.dg/g77/pr105203.f b/gcc/testsuite/gfortran.dg/g77/pr105203.f
new file mode 100644 (file)
index 0000000..3b47210
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/g77/pr105203.f
@@ -0,0 +1,20 @@
+C Test case for PR debug/105203
+C Origin: kmccarty@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