jump.c (never_reached_warning): Add finish argument.

	* jump.c (never_reached_warning): Add finish argument.
	If finish is NULL, stop on CODE_LABEL, otherwise stop before first
	real insn after end.
	* rtl.h (never_reached_warning): Adjust prototype.
	* cse.c (cse_insn): Pass NULL as finish to never_reached_warning.
	* cfgrtl.c (flow_delete_block): Pass b->end as finish to
	never_reached_warning.

	* gcc.dg/Wunreachable-1.c: New test.
	* gcc.dg/Wunreachable-2.c: New test.

From-SVN: r49713

8 files changed, 76 insertions, 11 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3b3ea3bfaa1..b9940e88046 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2002-02-12  Jakub Jelinek  <jakub@redhat.com>
+
+	* jump.c (never_reached_warning): Add finish argument.
+	If finish is NULL, stop on CODE_LABEL, otherwise stop before first
+	real insn after end.
+	* rtl.h (never_reached_warning): Adjust prototype.
+	* cse.c (cse_insn): Pass NULL as finish to never_reached_warning.
+	* cfgrtl.c (flow_delete_block): Pass b->end as finish to
+	never_reached_warning.
+
 2002-02-12  Graham Stott  <grahams@redhat.com>
 
 	* config/hp/pa.h (GO_IF_LEGITIMATE_ADDRESS): Fix typos.
diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 42358b2ccf0..5b99ab237e2 100644
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -338,7 +338,7 @@ flow_delete_block (b)
 
   insn = b->head;
 
-  never_reached_warning (insn);
+  never_reached_warning (insn, b->end);
 
   if (GET_CODE (insn) == CODE_LABEL)
     maybe_remove_eh_handler (insn);
diff --git a/gcc/cse.c b/gcc/cse.c
index ac9e8860d38..b88a84c2cea 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -5795,7 +5795,7 @@ cse_insn (insn, libcall_insn)
 	  else
 	    INSN_CODE (insn) = -1;
 
-	  never_reached_warning (insn);
+	  never_reached_warning (insn, NULL);
 
 	  /* Do not bother deleting any unreachable code,
 	     let jump/flow do that.  */
diff --git a/gcc/jump.c b/gcc/jump.c
index fcb3c61800b..fc6bef07e48 100644
--- a/gcc/jump.c
+++ b/gcc/jump.c
@@ -1913,13 +1913,12 @@ delete_for_peephole (from, to)
    so it's possible to get spurious warnings from this.  */
 
 void
-never_reached_warning (avoided_insn)
-     rtx avoided_insn;
+never_reached_warning (avoided_insn, finish)
+     rtx avoided_insn, finish;
 {
   rtx insn;
   rtx a_line_note = NULL;
-  int two_avoided_lines = 0;
-  int contains_insn = 0;
+  int two_avoided_lines = 0, contains_insn = 0, reached_end = 0;
 
   if (! warn_notreached)
     return;
@@ -1929,10 +1928,11 @@ never_reached_warning (avoided_insn)
 
   for (insn = avoided_insn; insn != NULL; insn = NEXT_INSN (insn))
     {
-      if (GET_CODE (insn) == CODE_LABEL)
+      if (finish == NULL && GET_CODE (insn) == CODE_LABEL)
 	break;
-      else if (GET_CODE (insn) == NOTE		/* A line number note?  */
-	       && NOTE_LINE_NUMBER (insn) >= 0)
+
+      if (GET_CODE (insn) == NOTE		/* A line number note?  */
+	  && NOTE_LINE_NUMBER (insn) >= 0)
 	{
 	  if (a_line_note == NULL)
 	    a_line_note = insn;
@@ -1941,7 +1941,14 @@ never_reached_warning (avoided_insn)
 				  != NOTE_LINE_NUMBER (insn));
 	}
       else if (INSN_P (insn))
-	contains_insn = 1;
+	{
+	  if (reached_end)
+	    break;
+	  contains_insn = 1;
+	}
+
+      if (insn == finish)
+	reached_end = 1;
     }
   if (two_avoided_lines && contains_insn)
     warning_with_file_and_line (NOTE_SOURCE_FILE (a_line_note),
diff --git a/gcc/rtl.h b/gcc/rtl.h
index ef4c5f8f146..99fabfcb3ff 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -1808,7 +1808,7 @@ extern enum rtx_code reversed_comparison_code_parts PARAMS ((enum rtx_code,
 							     rtx, rtx, rtx));
 extern void delete_for_peephole		PARAMS ((rtx, rtx));
 extern int condjump_in_parallel_p	PARAMS ((rtx));
-extern void never_reached_warning	PARAMS ((rtx));
+extern void never_reached_warning	PARAMS ((rtx, rtx));
 extern void purge_line_number_notes	PARAMS ((rtx));
 extern void copy_loop_headers		PARAMS ((rtx));
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2d3c7130f9a..d9766b06395 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2002-02-12  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/Wunreachable-1.c: New test.
+	* gcc.dg/Wunreachable-2.c: New test.
+
 2002-02-12  Joseph S. Myers  <jsm28@cam.ac.uk>
 
 	* gcc.dg/c90-const-expr-3.c, gcc.dg/c99-const-expr-3.c: New tests.
diff --git a/gcc/testsuite/gcc.dg/Wunreachable-1.c b/gcc/testsuite/gcc.dg/Wunreachable-1.c
new file mode 100644
index 00000000000..d6d59b481aa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wunreachable-1.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wunreachable-code" } */
+
+extern void foo (void);
+extern void baz (void);
+
+void bar (int i)
+{
+  if (i < 2)
+    {
+      baz ();
+      return;
+    }
+  else
+    {
+      if (i >= 4 && i <= 5)
+        foo ();
+      return;
+    }
+
+  baz ();	/* { dg-warning "will never be executed" "" } */
+  baz ();
+  baz ();
+}
diff --git a/gcc/testsuite/gcc.dg/Wunreachable-2.c b/gcc/testsuite/gcc.dg/Wunreachable-2.c
new file mode 100644
index 00000000000..8242441b0be
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wunreachable-2.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wunreachable-code" } */
+
+extern int foo (const char *);
+extern void baz (void);
+const char *a[] = { "one", "two" };
+
+void bar (void)
+{
+  int i;
+
+  for (i = 0; i < 2; i++)
+    if (! foo (a[i]))
+      return;
+
+  baz ();	/* { dg-bogus "will never be executed" } */
+  baz ();
+  baz ();
+}