re PR other/11370 (-Wunreachable-code gives false complaints)

	PR c/11370
	* calls.c (emit_call_1): Don't bother popping the arguments off of
	the stack after a noreturn function call;  The adjustment is dead.
	(expand_call): Likewise.

	* gcc.dg/Wunreachable-6.c: New testcase.
	* gcc.dg/Wunreachable-7.c: New testcase.

From-SVN: r69119

5 files changed, 60 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2d68c41..733ff95 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2003-07-08  Roger Sayle  <roger@eyesopen.com>
+
+	PR c/11370
+	* calls.c (emit_call_1): Don't bother popping the arguments off of
+	the stack after a noreturn function call;  The adjustment is dead.
+	(expand_call): Likewise.
+
 2003-07-08  Geoffrey Keating  <geoffk@apple.com>
 
 	* expr.c (MOVE_MAX_PIECES): Move from here...
diff --git a/gcc/calls.c b/gcc/calls.c
index 0415744..700564a 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -529,6 +529,10 @@ emit_call_1 (rtx funexp, tree fndecl ATTRIBUTE_UNUSED, tree funtype ATTRIBUTE_UN
      if the context of the call as a whole permits.  */
   inhibit_defer_pop = old_inhibit_defer_pop;
 
+  /* Don't bother cleaning up after a noreturn function.  */
+  if (ecf_flags & (ECF_NORETURN | ECF_LONGJMP))
+    return;
+
   if (n_popped > 0)
     {
       if (!already_popped)
@@ -3074,6 +3078,10 @@ expand_call (tree exp, rtx target, int ignore)
 	    }
 
 	  emit_barrier_after (last);
+
+	  /* Stack adjustments after a noreturn call are dead code.  */
+	  stack_pointer_delta = old_stack_allocated;
+	  pending_stack_adjust = 0;
 	}
 
       if (flags & ECF_LONGJMP)
@@ -3304,8 +3312,9 @@ expand_call (tree exp, rtx target, int ignore)
 	  normal_call_insns = insns;
 
 	  /* Verify that we've deallocated all the stack we used.  */
-	  if (old_stack_allocated !=
-	      stack_pointer_delta - pending_stack_adjust)
+	  if (! (flags & (ECF_NORETURN | ECF_LONGJMP))
+	      && old_stack_allocated != stack_pointer_delta
+					- pending_stack_adjust)
 	    abort ();
 	}
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5884c7f..cbd7cae 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2003-07-08  Roger Sayle  <roger@eyesopen.com>
+
+	PR c/11370
+	* gcc.dg/Wunreachable-6.c: New testcase.
+	* gcc.dg/Wunreachable-7.c: New testcase.
+
 2003-07-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c/11420
diff --git a/gcc/testsuite/gcc.dg/Wunreachable-6.c b/gcc/testsuite/gcc.dg/Wunreachable-6.c
new file mode 100644
index 0000000..77b6228
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wunreachable-6.c
@@ -0,0 +1,18 @@
+/* PR c/11370  */
+/* { dg-do compile } */
+/* { dg-options "-Wunreachable-code" } */
+
+int main(int argc, char *argv[])
+{
+  if (argc != 1)
+    exit(1);
+
+  {
+    int ix;  /* { dg-bogus "will never be executed" } */
+    ix = printf("hello\n");
+    printf("%d\n", ix);
+  }
+
+  return 0;
+}
+
diff --git a/gcc/testsuite/gcc.dg/Wunreachable-7.c b/gcc/testsuite/gcc.dg/Wunreachable-7.c
new file mode 100644
index 0000000..a19c94a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wunreachable-7.c
@@ -0,0 +1,18 @@
+/* PR c/11370  */
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wunreachable-code" } */
+
+int main(int argc, char *argv[])
+{
+  if (argc != 1)
+    exit(1);
+
+  {
+    int ix;  /* { dg-bogus "will never be executed" } */
+    ix = printf("hello\n");
+    printf("%d\n", ix);
+  }
+
+  return 0;
+}
+