xtensa: add -mauto-litpools option

With support from assembler this option allows compiling huge functions,
where single literal pool at the beginning of a function may not be
reachable by L32R instructions at its end.

Currently assembler --auto-litpools option cannot deal with literals
used from multiple locations separated by more than 256 KBytes of code.
Don't turn constants into literals, instead use MOVI instruction to load
them into registers and let the assembler turn them into literals as
necessary.

2015-08-12  Max Filippov  <jcmvbkbc@gmail.com>
gcc/
	* config/xtensa/constraints.md (define_constraint "Y"): New
	constraint.
	* config/xtensa/elf.h (ASM_SPEC): Add m(no-)auto-litpools.
	* config/xtensa/linux.h (ASM_SPEC): Likewise.
	* config/xtensa/predicates.md (move_operand): Match constants
	and symbols in the presence of TARGET_AUTO_LITPOOLS.
	* config/xtensa/xtensa.c (xtensa_valid_move): Don't allow
	immediate references to TLS data.
	(xtensa_emit_move_sequence): Don't force constants to memory in
	the presence of TARGET_AUTO_LITPOOLS.
	(print_operand): Add 'y' format, same as default, but capable of
	printing SF mode constants as well.
	* config/xtensa/xtensa.md (movsi_internal, movhi_internal)
	(movsf_internal): Add movi pattern that loads literal.
	(movsf, movdf): Don't force constants to memory in the presence
	of TARGET_AUTO_LITPOOLS.
	(movdf_internal): Add 'Y' constraint.
	* config/xtensa/xtensa.opt (mauto-litpools): New option.
	* doc/invoke.text (Xtensa options): Document -mauto-litpools.

From-SVN: r226828

gcc/ChangeLog

+2015-08-12  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* config/xtensa/constraints.md (define_constraint "Y"): New
+	constraint.
+	* config/xtensa/elf.h (ASM_SPEC): Add m(no-)auto-litpools.
+	* config/xtensa/linux.h (ASM_SPEC): Likewise.
+	* config/xtensa/predicates.md (move_operand): Match constants
+	and symbols in the presence of TARGET_AUTO_LITPOOLS.
+	* config/xtensa/xtensa.c (xtensa_valid_move): Don't allow
+	immediate references to TLS data.
+	(xtensa_emit_move_sequence): Don't force constants to memory in
+	the presence of TARGET_AUTO_LITPOOLS.
+	(print_operand): Add 'y' format, same as default, but capable of
+	printing SF mode constants as well.
+	* config/xtensa/xtensa.md (movsi_internal, movhi_internal)
+	(movsf_internal): Add movi pattern that loads literal.
+	(movsf, movdf): Don't force constants to memory in the presence
+	of TARGET_AUTO_LITPOOLS.
+	(movdf_internal): Add 'Y' constraint.
+	* config/xtensa/xtensa.opt (mauto-litpools): New option.
+	* doc/invoke.text (Xtensa options): Document -mauto-litpools.
+
 2015-08-12  Matthew Wahab  <matthew.wahab@arm.com>
 
 	* config/arm/arm-fpus.def: Replace booleans with feature flags.

gcc/config/xtensa/constraints.md

@@ -111,6 +111,11 @@
  (and (match_code "const_int")
       (match_test "xtensa_mask_immediate (ival)")))
 
+(define_constraint "Y"
+ "A constant that can be used in relaxed MOVI instructions."
+ (and (match_code "const_int,const_double,const,symbol_ref,label_ref")
+      (match_test "TARGET_AUTO_LITPOOLS")))
+
 ;; Memory constraints.  Do not use define_memory_constraint here.  Doing so
 ;; causes reload to force some constants into the constant pool, but since
 ;; the Xtensa constant pool can only be accessed with L32R instructions, it

gcc/config/xtensa/elf.h

@@ -48,7 +48,9 @@ along with GCC; see the file COPYING3.  If not see
   %{mtarget-align:--target-align} \
   %{mno-target-align:--no-target-align} \
   %{mlongcalls:--longcalls} \
-  %{mno-longcalls:--no-longcalls}"
+  %{mno-longcalls:--no-longcalls} \
+  %{mauto-litpools:--auto-litpools} \
+  %{mno-auto-litpools:--no-auto-litpools}"
 
 #undef LIB_SPEC
 #define LIB_SPEC "-lc -lsim -lc -lhandlers-sim -lhal"

gcc/config/xtensa/linux.h

@@ -42,7 +42,9 @@ along with GCC; see the file COPYING3.  If not see
   %{mtarget-align:--target-align} \
   %{mno-target-align:--no-target-align} \
   %{mlongcalls:--longcalls} \
-  %{mno-longcalls:--no-longcalls}"
+  %{mno-longcalls:--no-longcalls} \
+  %{mauto-litpools:--auto-litpools} \
+  %{mno-auto-litpools:--no-auto-litpools}"
 
 #define GLIBC_DYNAMIC_LINKER "/lib/ld.so.1"
 

gcc/config/xtensa/predicates.md

@@ -142,7 +142,8 @@
 	       (match_test "GET_MODE_CLASS (mode) == MODE_INT
 			    && xtensa_simm12b (INTVAL (op))"))
 	  (and (match_code "const_int,const_double,const,symbol_ref,label_ref")
-	       (match_test "TARGET_CONST16 && CONSTANT_P (op)
+	       (match_test "(TARGET_CONST16 || TARGET_AUTO_LITPOOLS)
+			    && CONSTANT_P (op)
 			    && GET_MODE_SIZE (mode) % UNITS_PER_WORD == 0")))))
 
 ;; Accept the floating point constant 1 in the appropriate mode.

gcc/config/xtensa/xtensa.c

@@ -480,6 +480,9 @@ xtensa_valid_move (machine_mode mode, rtx *operands)
     {
       int dst_regnum = xt_true_regnum (operands[0]);
 
+      if (xtensa_tls_referenced_p (operands[1]))
+	return FALSE;
+
       /* The stack pointer can only be assigned with a MOVSP opcode.  */
       if (dst_regnum == STACK_POINTER_REGNUM)
 	return !TARGET_WINDOWED_ABI
@@ -1048,7 +1051,7 @@ xtensa_emit_move_sequence (rtx *operands, machine_mode mode)
 	  return 1;
 	}
 
-      if (! TARGET_CONST16)
+      if (! TARGET_AUTO_LITPOOLS && ! TARGET_CONST16)
 	{
 	  src = force_const_mem (SImode, src);
 	  operands[1] = src;
@@ -2429,6 +2432,20 @@ print_operand (FILE *file, rtx x, int letter)
 	}
       break;
 
+    case 'y':
+      if (GET_CODE (x) == CONST_DOUBLE &&
+	  GET_MODE (x) == SFmode)
+	{
+	  REAL_VALUE_TYPE r;
+	  long l;
+	  REAL_VALUE_FROM_CONST_DOUBLE (r, x);
+	  REAL_VALUE_TO_TARGET_SINGLE (r, l);
+	  fprintf (file, "0x%08lx", l);
+	  break;
+	}
+
+      /* fall through */
+
     default:
       if (GET_CODE (x) == REG || GET_CODE (x) == SUBREG)
 	fprintf (file, "%s", reg_names[xt_true_regnum (x)]);

gcc/config/xtensa/xtensa.md

@@ -761,8 +761,8 @@
 })
 
 (define_insn "movsi_internal"
-  [(set (match_operand:SI 0 "nonimmed_operand" "=D,D,D,D,R,R,a,q,a,W,a,a,U,*a,*A")
-	(match_operand:SI 1 "move_operand" "M,D,d,R,D,d,r,r,I,i,T,U,r,*A,*r"))]
+  [(set (match_operand:SI 0 "nonimmed_operand" "=D,D,D,D,R,R,a,q,a,a,W,a,a,U,*a,*A")
+	(match_operand:SI 1 "move_operand" "M,D,d,R,D,d,r,r,I,Y,i,T,U,r,*A,*r"))]
   "xtensa_valid_move (SImode, operands)"
   "@
    movi.n\t%0, %x1
@@ -774,15 +774,16 @@
    mov\t%0, %1
    movsp\t%0, %1
    movi\t%0, %x1
+   movi\t%0, %1
    const16\t%0, %t1\;const16\t%0, %b1
    %v1l32r\t%0, %1
    %v1l32i\t%0, %1
    %v0s32i\t%1, %0
    rsr\t%0, ACCLO
    wsr\t%1, ACCLO"
-  [(set_attr "type" "move,move,move,load,store,store,move,move,move,move,load,load,store,rsr,wsr")
+  [(set_attr "type" "move,move,move,load,store,store,move,move,move,move,move,load,load,store,rsr,wsr")
    (set_attr "mode"	"SI")
-   (set_attr "length"	"2,2,2,2,2,2,3,3,3,6,3,3,3,3,3")])
+   (set_attr "length"	"2,2,2,2,2,2,3,3,3,3,6,3,3,3,3,3")])
 
 ;; 16-bit Integer moves
 
@@ -796,21 +797,22 @@
 })
 
 (define_insn "movhi_internal"
-  [(set (match_operand:HI 0 "nonimmed_operand" "=D,D,a,a,a,U,*a,*A")
-	(match_operand:HI 1 "move_operand" "M,d,r,I,U,r,*A,*r"))]
+  [(set (match_operand:HI 0 "nonimmed_operand" "=D,D,a,a,a,a,U,*a,*A")
+	(match_operand:HI 1 "move_operand" "M,d,r,I,Y,U,r,*A,*r"))]
   "xtensa_valid_move (HImode, operands)"
   "@
    movi.n\t%0, %x1
    mov.n\t%0, %1
    mov\t%0, %1
    movi\t%0, %x1
+   movi\t%0, %1
    %v1l16ui\t%0, %1
    %v0s16i\t%1, %0
    rsr\t%0, ACCLO
    wsr\t%1, ACCLO"
-  [(set_attr "type"	"move,move,move,move,load,store,rsr,wsr")
+  [(set_attr "type"	"move,move,move,move,move,load,store,rsr,wsr")
    (set_attr "mode"	"HI")
-   (set_attr "length"	"2,2,3,3,3,3,3,3")])
+   (set_attr "length"	"2,2,3,3,3,3,3,3,3")])
 
 ;; 8-bit Integer moves
 
@@ -881,7 +883,7 @@
 	(match_operand:SF 1 "general_operand" ""))]
   ""
 {
-  if (!TARGET_CONST16 && CONSTANT_P (operands[1]))
+  if (!TARGET_CONST16 && !TARGET_AUTO_LITPOOLS && CONSTANT_P (operands[1]))
     operands[1] = force_const_mem (SFmode, operands[1]);
 
   if ((!register_operand (operands[0], SFmode)
@@ -896,8 +898,8 @@
 })
 
 (define_insn "movsf_internal"
-  [(set (match_operand:SF 0 "nonimmed_operand" "=f,f,U,D,D,R,a,f,a,W,a,a,U")
-	(match_operand:SF 1 "move_operand" "f,U,f,d,R,d,r,r,f,iF,T,U,r"))]
+  [(set (match_operand:SF 0 "nonimmed_operand" "=f,f,U,D,D,R,a,f,a,a,W,a,a,U")
+	(match_operand:SF 1 "move_operand" "f,U,f,d,R,d,r,r,f,Y,iF,T,U,r"))]
   "((register_operand (operands[0], SFmode)
      || register_operand (operands[1], SFmode))
     && !(FP_REG_P (xt_true_regnum (operands[0]))
@@ -912,13 +914,14 @@
    mov\t%0, %1
    wfr\t%0, %1
    rfr\t%0, %1
+   movi\t%0, %y1
    const16\t%0, %t1\;const16\t%0, %b1
    %v1l32r\t%0, %1
    %v1l32i\t%0, %1
    %v0s32i\t%1, %0"
-  [(set_attr "type"	"farith,fload,fstore,move,load,store,move,farith,farith,move,load,load,store")
+  [(set_attr "type"	"farith,fload,fstore,move,load,store,move,farith,farith,move,move,load,load,store")
    (set_attr "mode"	"SF")
-   (set_attr "length"	"3,3,3,2,2,2,3,3,3,6,3,3,3")])
+   (set_attr "length"	"3,3,3,2,2,2,3,3,3,3,6,3,3,3")])
 
 (define_insn "*lsiu"
   [(set (match_operand:SF 0 "register_operand" "=f")
@@ -991,7 +994,7 @@
 	(match_operand:DF 1 "general_operand" ""))]
   ""
 {
-  if (CONSTANT_P (operands[1]) && !TARGET_CONST16)
+  if (CONSTANT_P (operands[1]) && !TARGET_CONST16 && !TARGET_AUTO_LITPOOLS)
     operands[1] = force_const_mem (DFmode, operands[1]);
 
   if (!register_operand (operands[0], DFmode)
@@ -1002,8 +1005,8 @@
 })
 
 (define_insn_and_split "movdf_internal"
-  [(set (match_operand:DF 0 "nonimmed_operand" "=a,W,a,a,U")
-	(match_operand:DF 1 "move_operand" "r,iF,T,U,r"))]
+  [(set (match_operand:DF 0 "nonimmed_operand" "=a,a,W,a,a,U")
+	(match_operand:DF 1 "move_operand" "r,Y,iF,T,U,r"))]
   "register_operand (operands[0], DFmode)
    || register_operand (operands[1], DFmode)"
   "#"

gcc/config/xtensa/xtensa.opt

@@ -38,6 +38,10 @@ mtext-section-literals
 Target
 Intersperse literal pools with code in the text section
 
+mauto-litpools
+Target Report Mask(AUTO_LITPOOLS)
+Relax literals in assembler and place them automatically in the text section
+
 mserialize-volatile
 Target Report Mask(SERIALIZE_VOLATILE)
 -mno-serialize-volatile	Do not serialize volatile memory references with MEMW instructions

gcc/doc/invoke.texi

@@ -1120,6 +1120,7 @@ See RS/6000 and PowerPC Options.
 -mforce-no-pic @gol
 -mserialize-volatile  -mno-serialize-volatile @gol
 -mtext-section-literals  -mno-text-section-literals @gol
+-mauto-litpools  -mno-auto-litpools @gol
 -mtarget-align  -mno-target-align @gol
 -mlongcalls  -mno-longcalls}
 
@@ -23605,7 +23606,23 @@ pools from separate object files to remove redundant literals and
 improve code size.  With @option{-mtext-section-literals}, the literals
 are interspersed in the text section in order to keep them as close as
 possible to their references.  This may be necessary for large assembly
-files.
+files.  Literals for each function are placed right before that function.
+
+@item -mauto-litpools
+@itemx -mno-auto-litpools
+@opindex mauto-litpools
+@opindex mno-auto-litpools
+These options control the treatment of literal pools.  The default is
+@option{-mno-auto-litpools}, which places literals in a separate
+section in the output file unless @option{-mtext-section-literals} is
+used.  With @option{-mauto-litpools} the literals are interspersed in
+the text section by the assembler.  Compiler does not produce explicit
+@code{.literal} directives and loads literals into registers with
+@code{MOVI} instructions instead of @code{L32R} to let the assembler
+do relaxation and place literals as necessary.  This option allows
+assembler to create several literal pools per function and assemble
+very big functions, which may not be possible with
+@option{-mtext-section-literals}.
 
 @item -mtarget-align
 @itemx -mno-target-align