PR middle-end/55030

	* builtins.c (expand_builtin_setjmp_receiver): Update comment
	regarding purpose of blockage.
	* emit-rtl.c [!HAVE_blockage] (gen_blockage): Similarly for
	the head comment.
	* rtlanal.c (volatile_insn_p): Ditto.
	* doc/md.texi (blockage): Update similarly.  Change wording to
	require one of two forms, rather than implying a wider choice.
	* cse.c (cse_insn): Where checking for blocking insns, use
	volatile_insn_p instead of manual check for volatile ASM.
	* dse.c (scan_insn): Ditto.
	* cselib.c (cselib_process_insn): Ditto.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193802 138bc75d-0d04-0410-961f-82ee72b054a4

8 files changed, 29 insertions, 15 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5c46d03d158..a682183fc78 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,18 @@
+2012-11-26  Hans-Peter Nilsson  <hp@bitrange.com>
+
+	PR middle-end/55030
+	* builtins.c (expand_builtin_setjmp_receiver): Update comment
+	regarding purpose of blockage.
+	* emit-rtl.c [!HAVE_blockage] (gen_blockage): Similarly for
+	the head comment.
+	* rtlanal.c (volatile_insn_p): Ditto.
+	* doc/md.texi (blockage): Update similarly.  Change wording to
+	require one of two forms, rather than implying a wider choice.
+	* cse.c (cse_insn): Where checking for blocking insns, use
+	volatile_insn_p instead of manual check for volatile ASM.
+	* dse.c (scan_insn): Ditto.
+	* cselib.c (cselib_process_insn): Ditto.
+
 2012-11-25  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/sse.md (<sse>_loadu<ssemodesuffix><avxsizesuffix>):
diff --git a/gcc/builtins.c b/gcc/builtins.c
index b0cab51556e..fb7b537ca2c 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -951,7 +951,8 @@ expand_builtin_setjmp_receiver (rtx receiver_label ATTRIBUTE_UNUSED)
 
   /* We must not allow the code we just generated to be reordered by
      scheduling.  Specifically, the update of the frame pointer must
-     happen immediately, not later.  */
+     happen immediately, not later.  Similarly, we must block
+     (frame-related) register values to be used across this code.  */
   emit_insn (gen_blockage ());
 }
 
diff --git a/gcc/cse.c b/gcc/cse.c
index 4d1d016dcf2..ff91b9d93f5 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -5661,10 +5661,9 @@ cse_insn (rtx insn)
 	  invalidate (XEXP (dest, 0), GET_MODE (dest));
       }
 
-  /* A volatile ASM invalidates everything.  */
+  /* A volatile ASM or an UNSPEC_VOLATILE invalidates everything.  */
   if (NONJUMP_INSN_P (insn)
-      && GET_CODE (PATTERN (insn)) == ASM_OPERANDS
-      && MEM_VOLATILE_P (PATTERN (insn)))
+      && volatile_insn_p (PATTERN (insn)))
     flush_hash_table ();
 
   /* Don't cse over a call to setjmp; on some machines (eg VAX)
diff --git a/gcc/cselib.c b/gcc/cselib.c
index 28f8d072438..198be8a3149 100644
--- a/gcc/cselib.c
+++ b/gcc/cselib.c
@@ -2625,13 +2625,12 @@ cselib_process_insn (rtx insn)
 
   cselib_current_insn = insn;
 
-  /* Forget everything at a CODE_LABEL, a volatile asm, or a setjmp.  */
+  /* Forget everything at a CODE_LABEL, a volatile insn, or a setjmp.  */
   if (LABEL_P (insn)
       || (CALL_P (insn)
 	  && find_reg_note (insn, REG_SETJMP, NULL))
       || (NONJUMP_INSN_P (insn)
-	  && GET_CODE (PATTERN (insn)) == ASM_OPERANDS
-	  && MEM_VOLATILE_P (PATTERN (insn))))
+	  && volatile_insn_p (PATTERN (insn))))
     {
       cselib_reset_table (next_uid);
       cselib_current_insn = NULL_RTX;
diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 482961bd9fe..4be4b55b3e2 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -5972,8 +5972,9 @@ the values of operands 1 and 2.
 @item @samp{blockage}
 
 This pattern defines a pseudo insn that prevents the instruction
-scheduler from moving instructions across the boundary defined by the
-blockage insn.  Normally an UNSPEC_VOLATILE pattern.
+scheduler and other passes from moving instructions and using register
+equivalences across the boundary defined by the blockage insn.
+This needs to be an UNSPEC_VOLATILE pattern or a volatile ASM.
 
 @cindex @code{memory_barrier} instruction pattern
 @item @samp{memory_barrier}
diff --git a/gcc/dse.c b/gcc/dse.c
index c7883f0138b..f879adb859e 100644
--- a/gcc/dse.c
+++ b/gcc/dse.c
@@ -2522,8 +2522,7 @@ scan_insn (bb_info_t bb_info, rtx insn)
   /* Cselib clears the table for this case, so we have to essentially
      do the same.  */
   if (NONJUMP_INSN_P (insn)
-      && GET_CODE (PATTERN (insn)) == ASM_OPERANDS
-      && MEM_VOLATILE_P (PATTERN (insn)))
+      && volatile_insn_p (PATTERN (insn)))
     {
       add_wild_read (bb_info);
       insn_info->cannot_delete = true;
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index 836ff2f5025..a15be5194b3 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -363,8 +363,8 @@ get_reg_attrs (tree decl, int offset)
 
 
 #if !HAVE_blockage
-/* Generate an empty ASM_INPUT, which is used to block attempts to schedule
-   across this insn. */
+/* Generate an empty ASM_INPUT, which is used to block attempts to schedule,
+   and to block register equivalences to be seen across this insn.  */
 
 rtx
 gen_blockage (void)
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index ecfae4ce9d5..382648188ed 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -2082,8 +2082,8 @@ remove_node_from_expr_list (const_rtx node, rtx *listp)
 
 /* Nonzero if X contains any volatile instructions.  These are instructions
    which may cause unpredictable machine state instructions, and thus no
-   instructions should be moved or combined across them.  This includes
-   only volatile asms and UNSPEC_VOLATILE instructions.  */
+   instructions or register uses should be moved or combined across them.
+   This includes only volatile asms and UNSPEC_VOLATILE instructions.  */
 
 int
 volatile_insn_p (const_rtx x)