re PR rtl-optimization/32450 (-pg causes miscompilation)

	PR rtl_optimization/32450
	* function.c (thread_prologue_and_epilogue_insns): Emit blockage insn
	to ensure that instructions are not moved into the prologue when
	profiling is on.  Remove unused prologue_end variable.
	(expand_function_end): Emit blockage insn instead of ASM_INPUT rtx
	as a scheduling barrier.

testsuite/ChangeLog:

	PR rtl_optimization/32450
	* gcc.dg/pr32450.c: New runtime test.

From-SVN: r126403

4 files changed, 59 insertions, 8 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 17a2edf..b36c380 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2007-07-06  Uros Bizjak  <ubizjak@gmail.com>
+
+	PR rtl_optimization/32450
+	* function.c (thread_prologue_and_epilogue_insns): Emit blockage insn
+	to ensure that instructions are not moved into the prologue when
+	profiling is on.  Remove unused prologue_end variable.
+	(expand_function_end): Emit blockage insn instead of ASM_INPUT rtx
+	as a scheduling barrier.
+
 2007-07-06  Alexandre Oliva  <aoliva@redhat.com>
 
 	PR debug/23551
diff --git a/gcc/function.c b/gcc/function.c
index a01bd93..1477b6a 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -4515,11 +4515,9 @@ expand_function_end (void)
 
   /* @@@ This is a kludge.  We want to ensure that instructions that
      may trap are not moved into the epilogue by scheduling, because
-     we don't always emit unwind information for the epilogue.
-     However, not all machine descriptions define a blockage insn, so
-     emit an ASM_INPUT to act as one.  */
+     we don't always emit unwind information for the epilogue.  */
   if (! USING_SJLJ_EXCEPTIONS && flag_non_call_exceptions)
-    emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
+    emit_insn (gen_blockage ());
 
   /* If stack protection is enabled for this function, check the guard.  */
   if (cfun->stack_protect_guard)
@@ -5045,9 +5043,6 @@ thread_prologue_and_epilogue_insns (void)
 #if defined (HAVE_sibcall_epilogue) || defined (HAVE_epilogue) || defined (HAVE_return) || defined (HAVE_prologue)
   rtx seq;
 #endif
-#ifdef HAVE_prologue
-  rtx prologue_end = NULL_RTX;
-#endif
 #if defined (HAVE_epilogue) || defined(HAVE_return)
   rtx epilogue_end = NULL_RTX;
 #endif
@@ -5067,7 +5062,15 @@ thread_prologue_and_epilogue_insns (void)
 
       /* Retain a map of the prologue insns.  */
       record_insns (seq, &prologue);
-      prologue_end = emit_note (NOTE_INSN_PROLOGUE_END);
+      emit_note (NOTE_INSN_PROLOGUE_END);
+ 
+#ifndef PROFILE_BEFORE_PROLOGUE
+      /* Ensure that instructions are not moved into the prologue when
+	 profiling is on.  The call to the profiling routine can be
+	 emitted within the live range of a call-clobbered register.  */
+      if (current_function_profile)
+        emit_insn (gen_blockage ());
+#endif
 
       seq = get_insns ();
       end_sequence ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index aa5d7ac..3772aff 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2007-07-06  Uros Bizjak  <ubizjak@gmail.com>
 
+	PR rtl_optimization/32450
+	* gcc.dg/pr32450.c: New runtime test.
+
+2007-07-06  Uros Bizjak  <ubizjak@gmail.com>
+
 	* g++.dg/ext/visibility/ms-compat-1.C: Change double underscore to
 	single underscore in scan directives.
 
diff --git a/gcc/testsuite/gcc.dg/pr32450.c b/gcc/testsuite/gcc.dg/pr32450.c
new file mode 100644
index 0000000..4a1842e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr32450.c
@@ -0,0 +1,34 @@
+/* Contributed by Joost VandeVondele  <jv244@cam.ac.uk> */
+
+/* { dg-do run } */
+/* { dg-require-profiling "-pg" } */
+/* { dg-options "-O2 -pg" } */
+/* { dg-options "-O2 -pg -mtune=core2" { target { i?86-*-* x86_64-*-* } } } */
+/* { dg-options "-O2 -pg -static" { target hppa*-*-hpux* } } */
+
+extern void abort (void);
+
+int stack_pointer;
+
+void
+__attribute__((noinline))
+mystop ()
+{
+  abort ();
+}
+
+void
+__attribute__((noinline))
+add ()
+{
+  if (stack_pointer + 1 > 10)
+    mystop ();
+
+  stack_pointer = stack_pointer + 1;
+}
+
+int main ()
+{
+  add ();
+  return stack_pointer - 1;
+}