RE: Patch H8/300 : Patch for -mexr option in case of function with "monitor" attribute

["Sherry Samuel" <SherryS at KPITCummins dot com>]

Hi,
	
The current implementation is, EXR is saved on stack by default for monitor function in case of H8S target. 
Following patch adds an option "-mno-exr", if this option is passed then EXR will not be saved on stack for 
monitor function in case of H8S target. If "-mexr" is passed, EXR will be saved on stack as like default case.

After conducting the regression test with the following patch applied in gcc-3.5-20040620 it was found that 
there is a regression in the test case in the following location.
	gcc-3.5-20040620/gcc/testsuite/gcc.c-torture/compile/20001226-1.c
The options for compiling was "-c -Os  -w -DSTACK_SIZE=4096 -c   -ms2600 -ms".

The following error was generated.

WARNING: program timed out.
compiler exited with status 1
FAIL: gcc.c-torture/compile/20001226-1.c (test for excess errors)
Excess errors:
exit status is 1

But when compiled separately there was no error coming with and without the following patch, though it took too
much time to compile because of nesting of macros. 

******************CHANGELOG TEXT*******************************************************************
2004-06-24  Sherry Samuel  <SherryS@KPITCummins.com>

	* h8300/h8300-protos.h : Declaration for function "h8300_current_function_monitor_function_p" is added.
	* h8300/h8300.h : Mask for EXR and target with mask is added. Target switch is added.
	* h8300/h8300.c (h8300_init_once) : Error message in case of target EXR is added.
	* h8300/h8300.c : New function is added to check whether current function is monitor function.
	* h8300/h8300.md : Use "rte" in epilogue for interrupt handler or monitor function.
				 Do not save EXR on stack for monitor function in case of H8S target when 
				 "-mno-exr" is passed.
	* doc/invoke.texi : H8/300 options and its description are updated with option "-mno-exr".


Patch Text
***************************************************************************************************

--- gcc/config/h8300/h8300-protos.h.old	2004-02-19 03:42:55.000000000 +0530
+++ gcc/config/h8300/h8300-protos.h	2004-06-24 12:40:09.000000000 +0530
@@ -102,6 +102,7 @@
 extern void h8300_expand_prologue (void);
 extern void h8300_expand_epilogue (void);
 extern int h8300_current_function_interrupt_function_p (void);
+extern int h8300_current_function_monitor_function_p (void);
 extern int h8300_initial_elimination_offset (int, int);
 extern int h8300_regs_ok_for_stm (int, rtx[]);
 extern int h8300_hard_regno_rename_ok (unsigned int, unsigned int);

--- gcc/config/h8300/h8300.h.old	2004-03-08 01:53:28.000000000 +0530
+++ gcc/config/h8300/h8300.h	2004-06-24 13:16:39.000000000 +0530
@@ -103,6 +103,7 @@
 #define MASK_RELAX		0x00000400
 #define MASK_H8300H		0x00001000
 #define MASK_ALIGN_300		0x00002000
+#define MASK_EXR		0x00004000
 
 /* Macros used in the machine description to test the flags.  */
 
@@ -135,6 +136,15 @@
    alignment.  */
 #define TARGET_ALIGN_300 (target_flags & MASK_ALIGN_300)
 
+/*
+ * Behaviour of RTE instruction depends on H8S model and operation mode.
+ *
+ * This affects only the prologue code generated for functions with
+ * monitor attribute!
+ * */
+#define TARGET_EXR (target_flags & MASK_EXR)
+
+
 /* Macro to define tables used to set the flags.
    This is a list in braces of pairs in braces,
    each pair being { "NAME", VALUE }
@@ -159,6 +169,8 @@
   {"n",			 MASK_NORMAL_MODE, N_("Enable the normal mode")},   \
   {"no-h",		-MASK_H8300H, N_("Do not generate H8/300H code")},  \
   {"align-300",		 MASK_ALIGN_300, N_("Use H8/300 alignment rules")}, \
+  {"exr",		 -MASK_EXR, N_("Push exr on stack")}, \
+  {"no-exr",	        MASK_EXR, N_("Do not push exr on stack")}, \
   { "",			 TARGET_DEFAULT, NULL}}
 
 #ifdef IN_LIBGCC2

--- gcc/config/h8300/h8300.c.old	2004-05-13 12:09:58.000000000 +0530
+++ gcc/config/h8300/h8300.c	2004-06-25 11:08:48.000000000 +0530
@@ -295,6 +295,12 @@
       target_flags ^= MASK_NORMAL_MODE;
     }
 
+    if (!TARGET_H8300S && TARGET_EXR)
+    {
+	 error ("-mno-exr is used without -ms");
+	 target_flags |= MASK_H8300S;
+ 	}
+
   /* Some of the shifts are optimized for speed by default.
      See http://gcc.gnu.org/ml/gcc-patches/2002-07/msg01858.html
      If optimizing for size, change shift_alg for those shift to
@@ -661,8 +667,14 @@
 int
 h8300_current_function_interrupt_function_p (void)
 {
-  return (h8300_interrupt_function_p (current_function_decl)
-	  || h8300_monitor_function_p (current_function_decl));
+  return (h8300_interrupt_function_p (current_function_decl));
+}
+
+
+int
+h8300_current_function_monitor_function_p ()
+{
+	return (h8300_monitor_function_p (current_function_decl));
 }
 
 /* Output assembly code for the start of the file.  */

--- gcc/config/h8300/h8300.md.old	2004-06-09 22:14:31.000000000 +0530
+++ gcc/config/h8300/h8300.md	2004-06-24 12:52:06.000000000 +0530
@@ -2157,6 +2157,8 @@
     return \"subs\\t#2,r7\;mov.w\\tr0,@-r7\;stc\\tccr,r0l\;mov.b\tr0l,@(2,r7)\;mov.w\\t@r7+,r0\;orc\t#128,ccr\";
   else if (TARGET_H8300H)
     return \"mov.l\\ter0,@-er7\;stc\\tccr,r0l\;mov.b\\tr0l,@(4,er7)\;mov.l\\t@er7+,er0\;orc\\t#128,ccr\";
+  else if (TARGET_H8300S && TARGET_EXR)
+     return \"mov.l\\ter0,@-er7\;stc\tccr,r0l\;mov.b\tr0l,@(4,er7)\;mov.l\\t@er7+,er0\;orc\t#128,ccr\";
   else if (TARGET_H8300S)
     return \"stc\texr,@-er7\;mov.l\\ter0,@-er7\;stc\tccr,r0l\;mov.b\tr0l,@(6,er7)\;mov.l\\t@er7+,er0\;orc\t#128,ccr\";
     abort ();

--- gcc/doc/invoke.texi.old	2004-06-19 22:59:00.000000000 +0530
+++ gcc/doc/invoke.texi	2004-06-25 11:02:26.000000000 +0530
@@ -547,7 +547,7 @@
 @gccoptlist{-mvms-return-codes}
 
 @emph{H8/300 Options}
-@gccoptlist{-mrelax  -mh  -ms  -mn  -mint32  -malign-300}
+@gccoptlist{-mrelax  -mh  -ms  -mn  -mno-exr  -mint32  -malign-300}
 
 @emph{SH Options}
 @gccoptlist{-m1  -m2  -m2e  -m3  -m3e @gol
@@ -9539,10 +9539,17 @@
 @opindex ms2600
 Generate code for the H8S/2600.  This switch must be used with @option{-ms}.
 
+@item -mno-exr
+@opindex mno-exr
+Extended registers are not stored on stack before execution of function 
+with monitor attribute. Default option is @option{-mexr}. 
+This option is valid only for H8S targets.
+
 @item -mint32
 @opindex mint32
 Make @code{int} data 32 bits by default.
 
+
 @item -malign-300
 @opindex malign-300
 On the H8/300H and H8S, use the same alignment rules as for the H8/300.

 

 

***************************************************************************************

	
Regards,
Sherry Samuel,
KPIT Cummins InfoSystems Ltd.
Pune, India

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-----Original Message-----
From: Kazu Hirata [mailto:kazu@cs.umass.edu]
Sent: Wednesday, June 09, 2004 2:51 PM
To: Anil Paranjape
Cc: gcc-patches@gcc.gnu.org
Subject: Re: Patch H8/300 : Patch for -mexr option in case of function
with "monitor" attribute


Hi Anil,

> In GCC 3.4, monitor function by default saves EXR on stack in case
> of H8S target.  In some H8S controllers this implementation is not
> needed.  Whenever user is required to store EXR on stack for monitor
> function, user must pass "-mexr" option to compiler with "-ms"
> switch.

IIRC, the default is to save EXR on H8S.  Are you suggesting to change
the default behavior of -ms?  I would preserve the current behavior
and provide -mno-exr (and -mexr for completeness).

Kazu Hirata