* config/rx/rx.opt (mallow-string-insns): New option.

	* config/rx/rx.c (RX_BUILTIN_RMPA): Disable the use of this
	builtin if string instructions are denied.
	* config/rx/rx.h (TARGET_CPU_CPP_BUILTINS): Define
	__RX_ALLOW_STRING_INSNS__ or __RX_DISALLOW_STRING_INSNS__, as
	appropriate.
	(ASM_SPEC): Pass -mno-allow-string-insns on to the assembler.
	* config/rx/rx.md (movstr): Enable pattern only if string
	instructions are allowed.
	(rx_movstr, rx_strend, movmemsi, rx_movmem): Likewise.
	(cmpstrnsi, cmpstrsi, rx_cmpstrn, rmpa): Likewise.
	* config/rx/t-rx (MULTILIB_OPTIONS): Add mno-allow-string-insns.
	(MULTILIB_DIRNAMES): Add no-strings.
	* doc/invoke.texi: Document -mno-allow-string-insns.

	* gcc.target/rx/builtins.c: Disable RMPA test if string
	instructions are not allowed.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@222116 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 80 insertions, 11 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c68a2fac882..7757d385574 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,19 @@
+2015-04-15  Nick Clifton  <nickc@redhat.com>
+
+	* config/rx/rx.opt (mallow-string-insns): New option.
+	* config/rx/rx.c (RX_BUILTIN_RMPA): Disable the use of this
+	builtin if string instructions are denied.
+	* config/rx/rx.h (TARGET_CPU_CPP_BUILTINS): Define
+	__RX_ALLOW_STRING_INSNS__ or __RX_DISALLOW_STRING_INSNS__, as
+	appropriate.
+	(ASM_SPEC): Pass -mno-allow-string-insns on to the assembler.
+	* config/rx/rx.md (movstr): Enable pattern only if string
+	instructions are allowed.
+	(rx_movstr, rx_strend, movmemsi, rx_movmem): Likewise.
+	(cmpstrnsi, cmpstrsi, rx_cmpstrn, rmpa): Likewise.
+	* config/rx/t-rx (MULTILIB_OPTIONS): Add mno-allow-string-insns.
+	(MULTILIB_DIRNAMES): Add no-strings.
+	* doc/invoke.texi: Document -mno-allow-string-insns.
 2015-04-15  Alan Modra  <amodra@gmail.com>
 
 	PR target/65408
diff --git a/gcc/config/rx/rx.c b/gcc/config/rx/rx.c
index 6fe21aab986..9180fe20f66 100644
--- a/gcc/config/rx/rx.c
+++ b/gcc/config/rx/rx.c
@@ -2620,7 +2620,12 @@ rx_expand_builtin (tree exp,
 	(op, gen_mvtachi, true);
     case RX_BUILTIN_MVTACLO: return rx_expand_void_builtin_1_arg
 	(op, gen_mvtaclo, true);
-    case RX_BUILTIN_RMPA:    emit_insn (gen_rmpa ()); return NULL_RTX;
+    case RX_BUILTIN_RMPA:
+      if (rx_allow_string_insns)
+	emit_insn (gen_rmpa ());
+      else
+	error ("-mno-allow-string-insns forbids the generation of the RMPA instruction");
+      return NULL_RTX;
     case RX_BUILTIN_MVFC:    return rx_expand_builtin_mvfc (arg, target);
     case RX_BUILTIN_MVTC:    return rx_expand_builtin_mvtc (exp);
     case RX_BUILTIN_MVTIPL:  return rx_expand_builtin_mvtipl (op);
diff --git a/gcc/config/rx/rx.h b/gcc/config/rx/rx.h
index 4c566247e71..238f340bf27 100644
--- a/gcc/config/rx/rx.h
+++ b/gcc/config/rx/rx.h
@@ -67,6 +67,11 @@
 	builtin_define ("__RX_GCC_ABI__");	\
       else					\
 	builtin_define ("__RX_ABI__");		\
+						\
+      if (rx_allow_string_insns)		\
+	builtin_define ("__RX_ALLOW_STRING_INSNS__"); \
+      else					\
+	builtin_define ("__RX_DISALLOW_STRING_INSNS__");\
     }                                           \
   while (0)
 
@@ -97,6 +102,7 @@
 %{msmall-data-limit*:-msmall-data-limit} \
 %{mrelax:-relax} \
 %{mpid} \
+%{mno-allow-string-insns} \
 %{mint-register=*} \
 %{mgcc-abi:-mgcc-abi} %{!mgcc-abi:-mrx-abi} \
 %{mcpu=*} \
diff --git a/gcc/config/rx/rx.md b/gcc/config/rx/rx.md
index 590c70f0f38..1e10327871d 100644
--- a/gcc/config/rx/rx.md
+++ b/gcc/config/rx/rx.md
@@ -2165,7 +2165,7 @@
 	(match_operand:BLK 2 "memory_operand"))   ;; Source
    (use (match_operand:SI  0 "register_operand")) ;; Updated Dest
   ]
-  ""
+  "rx_allow_string_insns"
   {
     rtx addr1 = gen_rtx_REG (SImode, 1);
     rtx addr2 = gen_rtx_REG (SImode, 2);
@@ -2192,7 +2192,7 @@
    (clobber (reg:SI 1))
    (clobber (reg:SI 2))
    (clobber (reg:SI 3))]
-  ""
+  "rx_allow_string_insns"
   "smovu"
   [(set_attr "length" "2")
    (set_attr "timings" "1111")] ;; The timing is a guesstimate.
@@ -2207,7 +2207,7 @@
    (clobber (reg:SI 3))
    (clobber (reg:CC CC_REG))
    ]
-  ""
+  "rx_allow_string_insns"
   "mov\t%1, r1\n\tmov\t#0, r2\n\tsuntil.b\n\tmov\tr1, %0\n\tsub\t#1, %0"
   [(set_attr "length" "10")
    (set_attr "timings" "1111")] ;; The timing is a guesstimate.
@@ -2221,7 +2221,7 @@
      (match_operand          3 "immediate_operand") ;; Align
      (unspec_volatile:BLK [(reg:SI 1) (reg:SI 2) (reg:SI 3)] UNSPEC_MOVMEM)]
     )]
-  ""
+  "rx_allow_string_insns"
   {
     rtx addr1 = gen_rtx_REG (SImode, 1);
     rtx addr2 = gen_rtx_REG (SImode, 2);
@@ -2263,7 +2263,7 @@
    (clobber (reg:SI 1))
    (clobber (reg:SI 2))
    (clobber (reg:SI 3))]
-  ""
+  "rx_allow_string_insns"
   "smovf"
   [(set_attr "length" "2")
    (set_attr "timings" "1111")] ;; The timing is a guesstimate.
@@ -2307,7 +2307,7 @@
 			    UNSPEC_CMPSTRN))
    (use (match_operand:SI                       3 "register_operand"))  ;; Max Length
    (match_operand:SI                            4 "immediate_operand")] ;; Known Align
-  ""
+  "rx_allow_string_insns"
   {
     rtx str1 = gen_rtx_REG (SImode, 1);
     rtx str2 = gen_rtx_REG (SImode, 2);
@@ -2328,7 +2328,7 @@
 			     (match_operand:BLK 2 "memory_operand")]    ;; String2
 			    UNSPEC_CMPSTRN))
    (match_operand:SI                            3 "immediate_operand")] ;; Known Align
-  ""
+  "rx_allow_string_insns"
   {
     rtx str1 = gen_rtx_REG (SImode, 1);
     rtx str2 = gen_rtx_REG (SImode, 2);
@@ -2353,7 +2353,7 @@
    (clobber (reg:SI 2))
    (clobber (reg:SI 3))
    (clobber (reg:CC CC_REG))]
-  ""
+  "rx_allow_string_insns"
   "scmpu		; Perform the string comparison
    mov     #-1, %0      ; Set up -1 result (which cannot be created
                         ; by the SC insn)
@@ -2471,7 +2471,7 @@
   (clobber (reg:SI 1))
   (clobber (reg:SI 2))
   (clobber (reg:SI 3))]
-  ""
+  "rx_allow_string_insns"
   "rmpa"
   [(set_attr "length" "2")
    (set_attr "timings" "1010")]
diff --git a/gcc/config/rx/rx.opt b/gcc/config/rx/rx.opt
index 1ccda4c2625..11113e2e305 100644
--- a/gcc/config/rx/rx.opt
+++ b/gcc/config/rx/rx.opt
@@ -128,6 +128,8 @@ mwarn-multiple-fast-interrupts
 Target Report Var(rx_warn_multiple_fast_interrupts) Init(1) Warning
 Warn when multiple, different, fast interrupt handlers are in the compilation unit.
 
+;---------------------------------------------------
+
 mgcc-abi
 Target RejectNegative Report Mask(GCC_ABI)
 Enable the use of the old, broken, ABI where all stacked function arguments are aligned to 32-bits.
@@ -136,6 +138,14 @@ mrx-abi
 Target RejectNegative Report InverseMask(GCC_ABI)
 Enable the use the standard RX ABI where all stacked function arguments are naturally aligned.  This is the default.
 
+;---------------------------------------------------
+
 mlra
 Target Report Mask(ENABLE_LRA)
 Enable the use of the LRA register allocator.
+
+;---------------------------------------------------
+
+mallow-string-insns
+Target Report Var(rx_allow_string_insns) Init(1)
+Enables or disables the use of the SMOVF, SMOVB, SMOVU, SUNTIL, SWHILE and RMPA instructions.  Enabled by default.
diff --git a/gcc/config/rx/t-rx b/gcc/config/rx/t-rx
index b532be6082d..f29fd3dc0a5 100644
--- a/gcc/config/rx/t-rx
+++ b/gcc/config/rx/t-rx
@@ -20,7 +20,7 @@
 
 # Enable multilibs:
 
-MULTILIB_OPTIONS    = m64bit-doubles  nofpu        mbig-endian-data  mpid
+MULTILIB_OPTIONS    = m64bit-doubles  mnofpu        mbig-endian-data  mpid
 MULTILIB_DIRNAMES   =  64-bit-double  no-fpu-libs   big-endian-data   pid
 
 # If necessary uncomment the next two lines to generate multilibs
@@ -28,6 +28,9 @@ MULTILIB_DIRNAMES   =  64-bit-double  no-fpu-libs   big-endian-data   pid
 # MULTILIB_OPTIONS    += mgcc-abi
 # MULTILIB_DIRNAMES   +=  gcc-abi
 
+MULTILIB_OPTIONS   += mno-allow-string-insns
+MULTILIB_DIRNAMES  += no-strings
+
 MULTILIB_MATCHES    = nofpu=mnofpu  nofpu=mcpu?rx200  nofpu=mcpu?rx100
 
 MULTILIB_EXCEPTIONS =
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 520c2c51ce6..18f69906248 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -940,6 +940,7 @@ See RS/6000 and PowerPC Options.
 -mmax-constant-size=@gol
 -mint-register=@gol
 -mpid@gol
+-mallow-string-insns -mno-allow-string-insns@gol
 -mno-warn-multiple-fast-interrupts@gol
 -msave-acc-in-interrupts}
 
@@ -20057,6 +20058,27 @@ fast interrupt handler when it is compiling a file.  The default is to
 issue a warning for each extra fast interrupt handler found, as the RX
 only supports one such interrupt.
 
+@item -mallow-string-insns
+@itemx -mno-allow-string-insns
+@opindex mallow-string-insns
+@opindex mno-allow-string-insns
+Enables or disables the use of the string manipulation instructions
+@code{SMOVF}, @code{SCMPU}, @code{SMOVB}, @code{SMOVU}, @code{SUNTIL}
+@code{SWHILE} and also the @code{RMPA} instruction.  These
+instructions may prefetch data, which is not safe to do if accessing
+an I/O register.  (See section 12.2.7 of the RX62N Group User's Manual
+for more information).
+
+The default is to allow these instructions, but it is not possible for
+GCC to reliably detect all circumstances where a string instruction
+might be used to access an I/O register, so their use cannot be
+disabled automatically.  Instead it is reliant upon the programmer to
+use the @option{-mno-allow-string-insns} option if their program
+accesses I/O space.
+
+When the instructions are enabled GCC defines the C preprocessor
+symbol @code{__RX_ALLOW_STRING_INSNS__}, otherwise it defines the
+symbol @code{__RX_DISALLOW_STRING_INSNS__}.
 @end table
 
 @emph{Note:} The generic GCC command-line option @option{-ffixed-@var{reg}}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index db3d1d325cd..a007f32bb9a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-04-15  Nick Clifton  <nickc@redhat.com>
+
+	* gcc.target/rx/builtins.c: Disable RMPA test if string
+	instructions are not allowed.
+
 2015-04-15  Alan Modra  <amodra@gmail.com>
 
 	* gcc.dg/pr65408.c: New.
diff --git a/gcc/testsuite/gcc.target/rx/builtins.c b/gcc/testsuite/gcc.target/rx/builtins.c
index d503ed3ef94..45071bb26df 100644
--- a/gcc/testsuite/gcc.target/rx/builtins.c
+++ b/gcc/testsuite/gcc.target/rx/builtins.c
@@ -137,8 +137,10 @@ wait (void)
   __builtin_rx_wait ();
 }
 
+#ifndef __RX_DISALLOW_STRING_INSNS__
 void
 rmpa (int * multiplicand, int * multiplier, int num)
 {
   __builtin_rx_rmpa ();
 }
+#endif