toplev.c (rest_of_compilation): Fix register_life_up_to_date handling...

	* toplev.c (rest_of_compilation): Fix register_life_up_to_date
	handling; move unconditional splitting before mode switching.

	* i386.md (type): Add fistp type.
	(i387, length_attr, scheduling definitions): Handle this type.
	(fix_trunc?f?i2): Revamp to use mode switching.
	(fix_trunct?f?i_nonmemory, fix_trunc?f?i_memory): New patterns.
	* i386.h (fp_cw_mode): New enum
	(OPTIMIZE_MODE_SWITCHING, NUM_MODES_FOR_MODE_SWITCHING, MODE_NEEDED,
	MODE_PRIORITY_TO_MODE, ENUM_MODE_SET): New macros.

From-SVN: r44027

gcc/ChangeLog

+Sun Jul 15 14:07:36 CEST 2001  Jan Hubicka  <jh@suse.cz>
+
+	* toplev.c (rest_of_compilation): Fix register_life_up_to_date
+	handling; move unconditional splitting before mode switching.
+
+	* i386.md (type): Add fistp type.
+	(i387, length_attr, scheduling definitions): Handle this type.
+	(fix_trunc?f?i2): Revamp to use mode switching.
+	(fix_trunct?f?i_nonmemory, fix_trunc?f?i_memory): New patterns.
+	* i386.h (fp_cw_mode): New enum
+	(OPTIMIZE_MODE_SWITCHING, NUM_MODES_FOR_MODE_SWITCHING, MODE_NEEDED,
+	MODE_PRIORITY_TO_MODE, ENUM_MODE_SET): New macros.
+
 Sun Jul 15 12:53:51 2001  Richard Kenner  <kenner@vlsi1.ultra.nyu.edu>
 
 	* Makefile.in (integrate.o): Add debug.h.

gcc/config/i386/i386.h

@@ -3118,6 +3118,69 @@ extern enum reg_class const regclass_map[];	/* smalled class containing REGNO */
 extern struct rtx_def *ix86_compare_op0;	/* operand 0 for comparisons */
 extern struct rtx_def *ix86_compare_op1;	/* operand 1 for comparisons */
 
+/* To properly truncate FP values into integers, we need to set i387 control
+   word.  We can't emit proper mode switching code before reload, as spills
+   generated by reload may truncate values incorrectly, but we still can avoid
+   redundant computation of new control word by the mode switching pass.
+   The fldcw instructions are still emitted redundantly, but this is probably
+   not going to be noticeable problem, as most CPUs do have fast path for
+   the sequence.  
+
+   The machinery is to emit simple truncation instructions and split them
+   before reload to instructions having USEs of two memory locations that
+   are filled by this code to old and new control word.
+ 
+   Post-reload pass may be later used to eliminate the redundant fildcw if
+   needed.  */
+
+enum fp_cw_mode {FP_CW_STORED, FP_CW_UNINITIALIZED, FP_CW_ANY};
+
+/* Define this macro if the port needs extra instructions inserted
+   for mode switching in an optimizing compilation.  */
+
+#define OPTIMIZE_MODE_SWITCHING(ENTITY) 1
+
+/* If you define `OPTIMIZE_MODE_SWITCHING', you have to define this as
+   initializer for an array of integers.  Each initializer element N
+   refers to an entity that needs mode switching, and specifies the
+   number of different modes that might need to be set for this
+   entity.  The position of the initializer in the initializer -
+   starting counting at zero - determines the integer that is used to
+   refer to the mode-switched entity in question.  */
+
+#define NUM_MODES_FOR_MODE_SWITCHING { FP_CW_ANY }
+
+/* ENTITY is an integer specifying a mode-switched entity.  If
+   `OPTIMIZE_MODE_SWITCHING' is defined, you must define this macro to
+   return an integer value not larger than the corresponding element
+   in `NUM_MODES_FOR_MODE_SWITCHING', to denote the mode that ENTITY
+   must be switched into prior to the execution of INSN.  */
+
+#define MODE_NEEDED(ENTITY, I)						\
+  (GET_CODE (I) == CALL_INSN						\
+   || (GET_CODE (I) == INSN && (asm_noperands (PATTERN (I)) >= 0 	\
+				|| GET_CODE (PATTERN (I)) == ASM_INPUT))\
+   ? FP_CW_UNINITIALIZED						\
+   : recog_memoized (I) < 0 || get_attr_type (I) != TYPE_FISTP		\
+   ? FP_CW_ANY								\
+   : FP_CW_STORED)
+
+/* This macro specifies the order in which modes for ENTITY are
+   processed.  0 is the highest priority.  */
+
+#define MODE_PRIORITY_TO_MODE(ENTITY, N) N
+
+/* Generate one or more insns to set ENTITY to MODE.  HARD_REG_LIVE
+   is the set of hard registers live at the point where the insn(s)
+   are to be inserted.  */
+
+#define EMIT_MODE_SET(ENTITY, MODE, HARD_REGS_LIVE) 			\
+  (MODE == FP_CW_STORED							\
+   ? emit_i387_cw_initialization (assign_386_stack_local (HImode, 1),	\
+				  assign_386_stack_local (HImode, 2)), 0\
+   : 0)
+
+
 /*
 Local variables:
 version-control: t

gcc/toplev.c

@@ -3327,7 +3327,6 @@ rest_of_compilation (decl)
   life_analysis (insns, rtl_dump_file, PROP_FINAL);
   timevar_pop (TV_FLOW);
 
-  register_life_up_to_date = 1;
   no_new_pseudos = 1;
 
   if (warn_uninitialized || extra_warnings)
@@ -3415,15 +3414,18 @@ rest_of_compilation (decl)
       ggc_collect ();
     }
 
+  /* Do unconditional splitting before register allocation to allow machine
+     description to add extra information not needed previously.  */
+  split_all_insns (1);
+
   /* Any of the several passes since flow1 will have munged register
      lifetime data a bit.  */
-  if (optimize > 0)
   register_life_up_to_date = 0;
 
 #ifdef OPTIMIZE_MODE_SWITCHING
   timevar_push (TV_GCSE);
 
-  no_new_pseudos = 1;
+  no_new_pseudos = 0;
   if (optimize_mode_switching (NULL))
     {
       /* We did work, and so had to regenerate global life information.
@@ -3431,15 +3433,13 @@ rest_of_compilation (decl)
 	 information below.  */
       register_life_up_to_date = 1;
     }
-  no_new_pseudos = 0;
+  no_new_pseudos = 1;
 
   timevar_pop (TV_GCSE);
 #endif
 
   timevar_push (TV_SCHED);
 
-  split_all_insns (1);
-
 #ifdef INSN_SCHEDULING
 
   /* Print function header into sched dump now