Getting rid of constrain_asm_operands

[Jeffrey A Law]

  In message <Pine.GSO.4.02A.9811282122510.10334-100000@jennifer.informatik.rwt
h-aachen.de>you write:
  > This is the next part of the extract_insn changes.  This patch eliminates
  > the constrain_asm_operands function in reg-stack.  Most of the work done
  > by it is now done by contrain_operands which can now handle asm statements,
  > and the rest of the work (analyzing the constraints) is done by a new
  > function "preprocess_constraints".  There are many places in the compiler
  > that have to parse constraint strings; quite a few of those could probably
  > be converted to use this function.  It might be extended to gather other
  > information as well (e.g., call operands_match_p for all pairs with matchin
  > g
  > constraints).
  > One drawback of the patch is that it introduces an arbitrary value
  > MAX_RECOG_ALTERNATIVES.  The chosen value (30) should be large enough and
  > can be increased if it ever turns out to be a problem.
  > 
  > The patch for final.c just removes some code that ought to be handled
  > transparently by extract_insn.
  > 
  > The patch was tested by building glibc-2.0.103 with it.  No errors in "make
  > check".
  > 
  > Bernd
  > 
  > 	* final.c (cleanup_subreg_operands): Delete some unused code.
  > 
  > 	* recog.h (MAX_RECOG_ALTERNATIVES): New macro.
  > 	(struct insn_alternative): New structure definition.
  > 	(recog_op_alt): Declare variable.
  > 	(preprocess_constraints): Declare function.
  > 	* recog.c (recog_op_alt): New variable.
  > 	(extract_insn): Verify number of alternatives is in range.
  > 	(preprocess_constraints): New function.
  > 	* reg-stack.c: Include recog.h.
  > 	(constrain_asm_operands): Delete.
  > 	(get_asm_operand_lengths): Delete.
  > 	(get_asm_operand_n_inputs): New function.
  > 	(record_asm_reg_life): Delete OPERANDS, CONSTRAINTS, N_INPUTS and
  > 	N_OUTPUTS args.  All callers changed.
  > 	Compute number of inputs and outputs here by calling
  > 	get_asm_operand_n_inputs.
  > 	Instead of constrain_asm_operands, call extract_insn,
  > 	constrain_operands and preprocess_constaints.  Use information
  > 	computed by these functions throughout.
  > 	(record_reg_life): Delete code that is unused due to changes in
  > 	record_asm_reg_life.
  > 	(subst_asm_stack_regs): Delete OPERANDS, OPERAND_LOC, CONSTRAINTS,
  > 	N_INPUTS and N_OUTPUTS args.  All callers changed.
  > 	Similar changes as in record_asm_reg_life.
  > 	(subst_stack_regs): Move n_operands declaration into the if statement
  > 	where it's used.
  > 	Delete code that is unused due to changes in subst_asm_stack_regs.
  > 	* stmt.c (expand_asm_operands): Verify number of alternatives is in
  > 	range.
  > 	* Makefile.in (reg-stack.o): Depend on recog.h.
Looks good to me.  The only change I'd like to see would be to rename this
field in struct operand_alternative:

+  /* The register class valid for this alternative (possibly NO_REGS).  */
+  enum reg_class cls;

Use "class".  It seems pretty silly to make the code harder to read in order
to save two characters :-)

If you could make that change and check in the updated patch it would be
greatly appreciated.

Thanks,
jeff