[PATCH] Fix some further gimple_clobber_p fallout (PR middle-end/51644)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The following testcases fail on the trunk, because at -O0
we don't decide to copy the finally stmts if there is more than one
destination.  That is of course desirable for debugging reasons if
there are any real stmts, but if the try/finally has been created only to
hold gimple_clobber_p stmts that will not result in any code generated
in those spots, we really should duplicate those.
The second hunk is to use the right costs for the clobber stmts, they
are expanded to nothing.  Without that for -O2 and perhaps many clobber
stmts we could still decide not to duplicate.  I guess it should help
inlining too if the costs much better the reality.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2011-12-21  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/51644
	PR middle-end/51647
	* tree-eh.c (decide_copy_try_finally): At -O0, return true
	even when ndests is not 1, if there are only gimple_clobber_p
	(or debug) stmts in the finally sequence.
	* tree-inline.c (estimate_num_insns): Return 0 for gimple_clobber_p
	stmts.

	* gcc.dg/pr51644.c: New test.
	* g++.dg/warn/Wreturn-4.C: New test.

--- gcc/tree-eh.c.jj	2011-12-14 08:11:03.000000000 +0100
+++ gcc/tree-eh.c	2011-12-21 12:15:49.749301513 +0100
@@ -1538,7 +1538,20 @@ decide_copy_try_finally (int ndests, boo
     }
 
   if (!optimize)
-    return ndests == 1;
+    {
+      gimple_stmt_iterator gsi;
+
+      if (ndests == 1)
+        return true;
+
+      for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt))
+	    return false;
+	}
+      return true;
+    }
 
   /* Finally estimate N times, plus N gotos.  */
   f_estimate = count_insns_seq (finally, &eni_size_weights);
--- gcc/tree-inline.c.jj	2011-12-14 08:11:03.000000000 +0100
+++ gcc/tree-inline.c	2011-12-21 11:17:04.708413203 +0100
@@ -3482,6 +3482,9 @@ estimate_num_insns (gimple stmt, eni_wei
 	 likely be a real store, so the cost of the GIMPLE_ASSIGN is the cost
 	 of moving something into "a", which we compute using the function
 	 estimate_move_cost.  */
+      if (gimple_clobber_p (stmt))
+	return 0;	/* ={v} {CLOBBER} stmt expands to nothing.  */
+
       lhs = gimple_assign_lhs (stmt);
       rhs = gimple_assign_rhs1 (stmt);
 
--- gcc/testsuite/gcc.dg/pr51644.c.jj	2011-12-21 12:24:22.185537200 +0100
+++ gcc/testsuite/gcc.dg/pr51644.c	2011-12-21 12:32:01.493946505 +0100
@@ -0,0 +1,33 @@
+/* PR middle-end/51644 */
+/* { dg-do compile } */
+/* { dg-options "-Wall -fexceptions" } */
+
+#include <stdarg.h>
+
+extern void baz (int, va_list) __attribute__ ((__noreturn__));
+
+__attribute__ ((__noreturn__))
+void
+foo (int s, ...)
+{
+  va_list ap;
+  va_start (ap, s);
+  baz (s, ap);
+  va_end (ap);
+}		/* { dg-bogus "function does return" } */
+
+__attribute__ ((__noreturn__))
+void
+bar (int s, ...)
+{
+  va_list ap1;
+  va_start (ap1, s);
+  {
+    va_list ap2;
+    va_start (ap2, s);
+    baz (s, ap1);
+    baz (s, ap2);
+    va_end (ap2);
+  }
+  va_end (ap1);
+}		/* { dg-bogus "function does return" } */
--- gcc/testsuite/g++.dg/warn/Wreturn-4.C.jj	2011-12-21 12:33:33.328428381 +0100
+++ gcc/testsuite/g++.dg/warn/Wreturn-4.C	2011-12-21 12:32:44.000000000 +0100
@@ -0,0 +1,48 @@
+// PR middle-end/51647
+// { dg-do compile }
+// { dg-options "-Wall" }
+
+enum PropertyAttributes { NONE = 1 };
+enum PropertyType { NORMAL = 0, FIELD = 1 };
+class LookupResult;
+
+template <typename T>
+struct Handle
+{
+  inline explicit Handle (T *obj) __attribute__ ((always_inline)) {}
+  inline T *operator-> () const __attribute__ ((always_inline)) { return 0; }
+};
+
+struct JSObject
+{
+  bool IsGlobalObject () { return false; }
+};
+
+struct Isolate
+{
+  LookupResult *top_lookup_result () { return 0; }
+};
+
+struct LookupResult
+{
+  explicit LookupResult (Isolate *isolate) {}
+  JSObject *holder () { return 0; }
+  PropertyType type () { return NORMAL; }
+};
+
+int
+test (LookupResult *lookup)
+{
+  Handle <JSObject> holder (lookup->holder ());
+  switch (lookup->type ())
+    {
+    case NORMAL:
+      if (holder->IsGlobalObject ())
+	return 2;
+      else
+	return 3;
+      break;
+    default:
+      return 4;
+    }
+}	// { dg-bogus "control reaches end of non-void function" }

	Jakub