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vax.h (CASE_DROPS_THROUGH): Don't define.

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* config/vax/vax.h (CASE_DROPS_THROUGH): Don't define.
	* config/vax/vax.md (casesi): Emit a test-and-branch to make sure
	that the case is in range, to make sure the casesi insn is always
	in range and never falls through.
	(casesi1): Add comment to explain why casesi never falls through.
	Remove the unnamed special case casesi pattern.

From-SVN: r91417
This commit is contained in:
Steven Bosscher 2004-11-28 12:01:20 +00:00
parent 69ffa7aa5a
commit 05dde071b3
3 changed files with 60 additions and 60 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2004-11-28 Steven Bosscher
John David Anglin <dave.anglin@nrc-cnrc.gc.ca>
* config/vax/vax.h (CASE_DROPS_THROUGH): Don't define.
* config/vax/vax.md (casesi): Emit a test-and-branch to make sure
that the case is in range, to make sure the casesi insn is always
in range and never falls through.
(casesi1): Add comment to explain why casesi never falls through.
Remove the unnamed special case casesi pattern.
2004-11-28 Hans-Peter Nilsson <hp@bitrange.com>
PR target/18331

5
gcc/config/vax/vax.h
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@ -784,11 +784,6 @@ enum reg_class { NO_REGS, ALL_REGS, LIM_REG_CLASSES };
Do not define this if the table should contain absolute addresses. */
#define CASE_VECTOR_PC_RELATIVE 1
/* Define this if the case instruction drops through after the table
when the index is out of range. Don't define it if the case insn
jumps to the default label instead. */
#define CASE_DROPS_THROUGH
/* Indicate that jump tables go in the text section. This is
necessary when compiling PIC code. */
#define JUMP_TABLES_IN_TEXT_SECTION 1

105
gcc/config/vax/vax.md
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@ -1960,68 +1960,63 @@
"jmp (%0)")
;; This is here to accept 5 arguments (as passed by expand_end_case)
;; and pass the first 4 along to the casesi1 pattern that really does the work.
;; and pass the first 4 along to the casesi1 pattern that really does
;; the actual casesi work. We emit a jump here to the default label
;; _before_ the casesi so that we can be sure that the casesi never
;; drops through.
;; This is suboptimal perhaps, but so is much of the rest of this
;; machine description. For what it's worth, HPPA uses the same trick.
;;
;; operand 0 is index
;; operand 1 is the minimum bound (a const_int)
;; operand 2 is the maximum bound - minimum bound + 1 (also a const_int)
;; operand 3 is CODE_LABEL for the table;
;; operand 4 is the CODE_LABEL to go to if index out of range (ie. default).
;;
;; We emit:
;; i = index - minimum_bound
;; if (i > (maximum_bound - minimum_bound + 1) goto default;
;; casesi (i, 0, table);
;;
(define_expand "casesi"
[(match_operand:SI 0 "general_operand" "") ; index
(match_operand:SI 1 "general_operand" "") ; lower
(match_operand:SI 2 "general_operand" "") ; upper-lower
(match_operand 3 "" "") ; table label
(match_operand 4 "" "")] ; default label
[(match_operand:SI 0 "general_operand" "")
(match_operand:SI 1 "general_operand" "")
(match_operand:SI 2 "general_operand" "")
(match_operand 3 "" "")
(match_operand 4 "" "")]
""
{
emit_jump_insn (gen_casesi1 (operands[0], operands[1],
operands[2], operands[3]));
/* i = index - minimum_bound;
But only if the lower bound is not already zero. */
if (operands[1] != const0_rtx)
{
rtx index = gen_reg_rtx (SImode);
emit_insn (gen_addsi3 (index,
operands[0],
GEN_INT (-INTVAL (operands[1]))));
operands[0] = index;
}
/* if (i > (maximum_bound - minimum_bound + 1) goto default; */
emit_insn (gen_cmpsi (operands[0], operands[2]));
emit_jump_insn (gen_bgtu (operands[4]));
/* casesi (i, 0, table); */
emit_jump_insn (gen_casesi1 (operands[0], operands[2], operands[3]));
DONE;
})
;; This insn is a bit of a lier. It actually falls through if no case
;; matches. But, we prevent that from ever happening by emiting a jump
;; before this, see the define_expand above.
(define_insn "casesi1"
[(set (pc)
(if_then_else
(leu (minus:SI (match_operand:SI 0 "general_operand" "g")
(match_operand:SI 1 "general_operand" "g"))
(match_operand:SI 2 "general_operand" "g"))
(plus:SI (sign_extend:SI
(mem:HI (plus:SI (mult:SI (minus:SI (match_dup 0)
(match_dup 1))
(const_int 2))
(pc))))
(label_ref:SI (match_operand 3 "" "")))
(pc)))]
""
"casel %0,%1,%2")
;; This can arise by simplification when operand 1 is a constant int.
(define_insn ""
[(set (pc)
(if_then_else
(leu (plus:SI (match_operand:SI 0 "general_operand" "g")
(match_operand:SI 1 "const_int_operand" "n"))
(match_operand:SI 2 "general_operand" "g"))
(plus:SI (sign_extend:SI
(mem:HI (plus:SI (mult:SI (plus:SI (match_dup 0)
(match_dup 1))
(const_int 2))
(pc))))
(label_ref:SI (match_operand 3 "" "")))
(pc)))]
""
"*
{
operands[1] = GEN_INT (-INTVAL (operands[1]));
return \"casel %0,%1,%2\";
}")
;; This can arise by simplification when the base for the case insn is zero.
(define_insn ""
[(set (pc)
(if_then_else (leu (match_operand:SI 0 "general_operand" "g")
(match_operand:SI 1 "general_operand" "g"))
(plus:SI (sign_extend:SI
(mem:HI (plus:SI (mult:SI (match_dup 0)
(const_int 2))
(pc))))
(label_ref:SI (match_operand 2 "" "")))
(pc)))]
[(match_operand:SI 1 "const_int_operand" "n")
(set (pc)
(plus:SI (sign_extend:SI
(mem:HI (plus:SI (mult:SI (match_operand:SI 0 "general_operand" "g")
(const_int 2))
(pc))))
(label_ref:SI (match_operand 2 "" ""))))]
""
"casel %0,$0,%1")