PR middle-end/32758

	* dce.c (dce_process_block): Don't delete setters of
	artificially used registers.

	* gcc.dg/cleanup-12.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@127923 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 88 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e332be879d8..f0254593a26 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -5,6 +5,10 @@
 	SImode and update m.  Don't run gen_lowpart_common on arbitrary
 	memory address, force it to register first.
 
+	PR middle-end/32758
+	* dce.c (dce_process_block): Don't delete setters of
+	artificially used registers.
+
 2007-08-30  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>
 
 	* config/s390/s390.md ("*add<mode>3_alc_carry1_cc",
diff --git a/gcc/dce.c b/gcc/dce.c
index c9ff13fa17b..c5af55ecc12 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -527,6 +527,7 @@ static bool
 dce_process_block (basic_block bb, bool redo_out)
 {
   bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
+  bitmap au;
   rtx insn;
   bool block_changed;
   struct df_ref **def_rec, **use_rec;
@@ -569,6 +570,15 @@ dce_process_block (basic_block bb, bool redo_out)
 	bitmap_set_bit (local_live, DF_REF_REGNO (use));
     }
 
+  /* These regs are considered always live so if they end up dying
+     because of some def, we need to bring the back again.
+     Calling df_simulate_fixup_sets has the disadvantage of calling
+     df_has_eh_preds once per insn, so we cache the information here.  */
+  if (df_has_eh_preds (bb))
+    au = df->eh_block_artificial_uses;
+  else
+    au = df->regular_block_artificial_uses;
+
   FOR_BB_INSNS_REVERSE (bb, insn)
     if (INSN_P (insn))
       {
@@ -580,7 +590,8 @@ dce_process_block (basic_block bb, bool redo_out)
 
 	    /* The insn is needed if there is someone who uses the output.  */
 	    for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
-	      if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec)))
+	      if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
+		  || bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
 		{
 		  needed = true;
 		  break;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8e6ffd5904a..0fd46770896 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -4,6 +4,9 @@
 	(AI): Add AI_ALIGN.
 	* gcc.dg/sync-3.c: New test.
 
+	PR middle-end/32758
+	* gcc.dg/cleanup-12.c: New test.
+
 2007-08-30  Uros Bizjak  <ubizjak@gmail.com>
 
 	* lib/gcc-dg.exp (cleanup-profile-file): New procedure.
diff --git a/gcc/testsuite/gcc.dg/cleanup-12.c b/gcc/testsuite/gcc.dg/cleanup-12.c
new file mode 100644
index 00000000000..90de90ac831
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/cleanup-12.c
@@ -0,0 +1,69 @@
+/* PR middle-end/32758 */
+/* HP-UX libunwind.so doesn't provide _UA_END_OF_STACK */
+/* { dg-do run } */
+/* { dg-options "-O2 -fexceptions" } */
+/* { dg-skip-if "" { "ia64-*-hpux11.*" }  { "*" } { "" } } */
+/* Verify unwind info in presence of alloca.  */
+
+#include <unwind.h>
+#include <stdlib.h>
+#include <string.h>
+
+static _Unwind_Reason_Code
+force_unwind_stop (int version, _Unwind_Action actions,
+		   _Unwind_Exception_Class exc_class,
+		   struct _Unwind_Exception *exc_obj,
+		   struct _Unwind_Context *context,
+		   void *stop_parameter)
+{
+  if (actions & _UA_END_OF_STACK)
+    abort ();
+  return _URC_NO_REASON;
+}
+
+static void force_unwind (void)
+{
+  struct _Unwind_Exception *exc = malloc (sizeof (*exc));
+  memset (&exc->exception_class, 0, sizeof (exc->exception_class));
+  exc->exception_cleanup = 0;
+
+#ifndef __USING_SJLJ_EXCEPTIONS__
+  _Unwind_ForcedUnwind (exc, force_unwind_stop, 0);
+#else
+  _Unwind_SjLj_ForcedUnwind (exc, force_unwind_stop, 0);
+#endif
+
+  abort ();
+}
+
+__attribute__((noinline))
+void foo (void *x __attribute__((unused)))
+{
+  force_unwind ();
+}
+
+__attribute__((noinline))
+int bar (unsigned int x)
+{
+  void *y = __builtin_alloca (x);
+  foo (y);
+  return 1;
+}
+
+static void handler (void *p __attribute__((unused)))
+{
+  exit (0);
+}
+
+__attribute__((noinline))
+static void doit ()
+{
+  char dummy __attribute__((cleanup (handler)));
+  bar (1024);
+}
+
+int main ()
+{
+  doit ();
+  abort ();
+}