re PR rtl-optimization/28726 (-fsched2-use-superblock produces wrong code)

	PR rtl-optimization/28726
	* sched-deps.c (sched_analyze_reg): New function extracted from...
	(sched_analyze_1): ...here.  Call it to analyze references to
	registers.  Treat again writes to a stack register as writing to the
	register.
	(sched_analyze_2): ...and here.  Call it to analyze references to
	registers.  Treat again reads of a stack register as reading the
	register.

From-SVN: r116855

gcc/ChangeLog

+2006-09-11  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR rtl-optimization/28726
+	* sched-deps.c (sched_analyze_reg): New function extracted from...
+	(sched_analyze_1): ...here.  Call it to analyze references to
+	registers.  Treat again writes to a stack register as writing to the
+	register.
+	(sched_analyze_2): ...and here.  Call it to analyze references to
+	registers.  Treat again reads of a stack register as reading the
+	register.
+
 2006-09-11  Guenter Roeck  <guenter@roeck-us.net>
 	    David Edelsohn  <edelsohn@gnu.org>
 

gcc/sched-deps.c

@@ -715,6 +715,78 @@ flush_pending_lists (struct deps *deps, rtx insn, int for_read,
   deps->pending_flush_length = 1;
 }
 
+/* Analyze a single reference to register (reg:MODE REGNO) in INSN.
+   The type of the reference is specified by REF and can be SET,
+   CLOBBER, PRE_DEC, POST_DEC, PRE_INC, POST_INC or USE.  */
+
+static void
+sched_analyze_reg (struct deps *deps, int regno, enum machine_mode mode,
+		   enum rtx_code ref, rtx insn)
+{
+  /* A hard reg in a wide mode may really be multiple registers.
+     If so, mark all of them just like the first.  */
+  if (regno < FIRST_PSEUDO_REGISTER)
+    {
+      int i = hard_regno_nregs[regno][mode];
+      if (ref == SET)
+	{
+	  while (--i >= 0)
+	    SET_REGNO_REG_SET (reg_pending_sets, regno + i);
+	}
+      else if (ref == USE)
+	{
+	  while (--i >= 0)
+	    SET_REGNO_REG_SET (reg_pending_uses, regno + i);
+	}
+      else
+	{
+	  while (--i >= 0)
+	    SET_REGNO_REG_SET (reg_pending_clobbers, regno + i);
+	}
+    }
+
+  /* ??? Reload sometimes emits USEs and CLOBBERs of pseudos that
+     it does not reload.  Ignore these as they have served their
+     purpose already.  */
+  else if (regno >= deps->max_reg)
+    {
+      enum rtx_code code = GET_CODE (PATTERN (insn));
+      gcc_assert (code == USE || code == CLOBBER);
+    }
+
+  else
+    {
+      if (ref == SET)
+	SET_REGNO_REG_SET (reg_pending_sets, regno);
+      else if (ref == USE)
+	SET_REGNO_REG_SET (reg_pending_uses, regno);
+      else
+	SET_REGNO_REG_SET (reg_pending_clobbers, regno);
+
+      /* Pseudos that are REG_EQUIV to something may be replaced
+	 by that during reloading.  We need only add dependencies for
+	the address in the REG_EQUIV note.  */
+      if (!reload_completed && get_reg_known_equiv_p (regno))
+	{
+	  rtx t = get_reg_known_value (regno);
+	  if (MEM_P (t))
+	    sched_analyze_2 (deps, XEXP (t, 0), insn);
+	}
+
+      /* Don't let it cross a call after scheduling if it doesn't
+	 already cross one.  */
+      if (REG_N_CALLS_CROSSED (regno) == 0)
+	{
+	  if (ref == USE)
+	    deps->sched_before_next_call
+	      = alloc_INSN_LIST (insn, deps->sched_before_next_call);
+	  else
+	    add_dependence_list (insn, deps->last_function_call, 1,
+				 REG_DEP_ANTI);
+	}
+    }
+}
+
 /* Analyze a single SET, CLOBBER, PRE_DEC, POST_DEC, PRE_INC or POST_INC
    rtx, X, creating all dependencies generated by the write to the
    destination of X, and reads of everything mentioned.  */
@@ -722,7 +794,6 @@ flush_pending_lists (struct deps *deps, rtx insn, int for_read,
 static void
 sched_analyze_1 (struct deps *deps, rtx x, rtx insn)
 {
-  int regno;
   rtx dest = XEXP (x, 0);
   enum rtx_code code = GET_CODE (x);
 
@@ -771,64 +842,21 @@ sched_analyze_1 (struct deps *deps, rtx x, rtx insn)
 
   if (REG_P (dest))
     {
-      regno = REGNO (dest);
+      int regno = REGNO (dest);
+      enum machine_mode mode = GET_MODE (dest);
+
+      sched_analyze_reg (deps, regno, mode, code, insn);
 
 #ifdef STACK_REGS
       /* Treat all writes to a stack register as modifying the TOS.  */
       if (regno >= FIRST_STACK_REG && regno <= LAST_STACK_REG)
 	{
-	  SET_REGNO_REG_SET (reg_pending_uses, FIRST_STACK_REG);
-	  regno = FIRST_STACK_REG;
+	  /* Avoid analyzing the same register twice.  */
+	  if (regno != FIRST_STACK_REG)
+	    sched_analyze_reg (deps, FIRST_STACK_REG, mode, code, insn);
+	  sched_analyze_reg (deps, FIRST_STACK_REG, mode, USE, insn);
 	}
 #endif
-
-      /* A hard reg in a wide mode may really be multiple registers.
-         If so, mark all of them just like the first.  */
-      if (regno < FIRST_PSEUDO_REGISTER)
-	{
-	  int i = hard_regno_nregs[regno][GET_MODE (dest)];
-	  if (code == SET)
-	    {
-	      while (--i >= 0)
-		SET_REGNO_REG_SET (reg_pending_sets, regno + i);
-	    }
-	  else
-	    {
-	      while (--i >= 0)
-		SET_REGNO_REG_SET (reg_pending_clobbers, regno + i);
-	    }
-	}
-      /* ??? Reload sometimes emits USEs and CLOBBERs of pseudos that
-	 it does not reload.  Ignore these as they have served their
-	 purpose already.  */
-      else if (regno >= deps->max_reg)
-	{
-	  gcc_assert (GET_CODE (PATTERN (insn)) == USE
-		      || GET_CODE (PATTERN (insn)) == CLOBBER);
-	}
-      else
-	{
-	  if (code == SET)
-	    SET_REGNO_REG_SET (reg_pending_sets, regno);
-	  else
-	    SET_REGNO_REG_SET (reg_pending_clobbers, regno);
-
-	  /* Pseudos that are REG_EQUIV to something may be replaced
-	     by that during reloading.  We need only add dependencies for
-	     the address in the REG_EQUIV note.  */
-	  if (!reload_completed && get_reg_known_equiv_p (regno))
-	    {
-	      rtx t = get_reg_known_value (regno);
-	      if (MEM_P (t))
-	        sched_analyze_2 (deps, XEXP (t, 0), insn);
-	    }
-
-	  /* Don't let it cross a call after scheduling if it doesn't
-	     already cross one.  */
-	  if (REG_N_CALLS_CROSSED (regno) == 0)
-	    add_dependence_list (insn, deps->last_function_call, 1,
-				 REG_DEP_ANTI);
-	}
     }
   else if (MEM_P (dest))
     {
@@ -935,51 +963,20 @@ sched_analyze_2 (struct deps *deps, rtx x, rtx insn)
     case REG:
       {
 	int regno = REGNO (x);
+	enum machine_mode mode = GET_MODE (x);
+
+	sched_analyze_reg (deps, regno, mode, USE, insn);
 
 #ifdef STACK_REGS
       /* Treat all reads of a stack register as modifying the TOS.  */
       if (regno >= FIRST_STACK_REG && regno <= LAST_STACK_REG)
 	{
-	  SET_REGNO_REG_SET (reg_pending_sets, FIRST_STACK_REG);
-	  regno = FIRST_STACK_REG;
+	  /* Avoid analyzing the same register twice.  */
+	  if (regno != FIRST_STACK_REG)
+	    sched_analyze_reg (deps, FIRST_STACK_REG, mode, USE, insn);
+	  sched_analyze_reg (deps, FIRST_STACK_REG, mode, SET, insn);
 	}
 #endif
-
-	if (regno < FIRST_PSEUDO_REGISTER)
-	  {
-	    int i = hard_regno_nregs[regno][GET_MODE (x)];
-	    while (--i >= 0)
-	      SET_REGNO_REG_SET (reg_pending_uses, regno + i);
-	  }
-	/* ??? Reload sometimes emits USEs and CLOBBERs of pseudos that
-	   it does not reload.  Ignore these as they have served their
-	   purpose already.  */
-	else if (regno >= deps->max_reg)
-	  {
-	    gcc_assert (GET_CODE (PATTERN (insn)) == USE
-			|| GET_CODE (PATTERN (insn)) == CLOBBER);
-	  }
-	else
-	  {
-	    SET_REGNO_REG_SET (reg_pending_uses, regno);
-
-	    /* Pseudos that are REG_EQUIV to something may be replaced
-	       by that during reloading.  We need only add dependencies for
-	       the address in the REG_EQUIV note.  */
-	    if (!reload_completed && get_reg_known_equiv_p (regno))
-	      {
-		rtx t = get_reg_known_value (regno);
-		if (MEM_P (t))
-		  sched_analyze_2 (deps, XEXP (t, 0), insn);
-	      }
-
-	    /* If the register does not already cross any calls, then add this
-	       insn to the sched_before_next_call list so that it will still
-	       not cross calls after scheduling.  */
-	    if (REG_N_CALLS_CROSSED (regno) == 0)
-	      deps->sched_before_next_call
-		= alloc_INSN_LIST (insn, deps->sched_before_next_call);
-	  }
 	return;
       }
 

gcc/testsuite/ChangeLog

+2006-09-11  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	* gcc.dg/pr28726.c: New test.
+
 2006-09-11  Josh Conner  <jconner@apple.com>
 
 	* gcc.dg/nrv3.c: Increase size of structure.

gcc/testsuite/gcc.dg/pr28726.c

+/* PR rtl-optimization/28726 */
+/* Origin: Sigurd Schneider <sg313d@gmail.com> */
+
+/* { dg-do run } */
+/* { dg-options "-O2 -fsched2-use-superblocks" } */
+
+extern void abort (void);
+
+static double my_loop(void) __attribute__((noinline));
+
+static double my_loop(void)
+{
+  double retval = 0.0;
+  const unsigned char *start = "\005\b\000";
+  const unsigned char *const end = start + 2;
+
+  while (start < end)
+    retval += *start++;
+
+  return retval;
+}
+
+int main(void)
+{
+  if (my_loop() != 13.0)
+    abort ();
+
+  return 0;
+}