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arm.md (cbranchsi4): Correct calculation of branch ranges.

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* arm.md (cbranchsi4): Correct calculation of branch ranges.
(negated_cbranchsi4): Likewise.

From-SVN: r39039
This commit is contained in:
Richard Earnshaw 2001-01-15 16:17:08 +00:00 committed by Richard Earnshaw
parent b3c5b2be07
commit 6c98269caa
2 changed files with 25 additions and 5 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2001-01-15 Richard Earnshaw <rearnsha@arm.com>
* arm.md (cbranchsi4): Correct calculation of branch ranges.
(negated_cbranchsi4): Likewise.
2001-01-15 Richard Earnshaw <rearnsha@arm.com>
* config/arm/semi.h (SUBTARGET_EXTRA_SPECS): Define.

25
gcc/config/arm/arm.md
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@ -5520,7 +5520,22 @@
;; Comapre & branch insns
;; Compare & branch insns
;; The range calcualations are based as follows:
;; For forward branches, the address calculation returns the address of
;; the next instruction. This is 2 beyond the branch instruction.
;; For backward branches, the address calculation returns the address of
;; the first instruction in this pattern (cmp). This is 2 before the branch
;; instruction for the shortest sequence, and 4 before the branch instruction
;; if we have to jump around an unconditional branch.
;; To the basic branch range the PC offset must be added (this is +4).
;; So for forward branches we have
;; (pos_range - pos_base_offs + pc_offs) = (pos_range - 2 + 4).
;; And for backward branches we have
;; (neg_range - neg_base_offs + pc_offs) = (neg_range - (-2 or -4) + 4).
;;
;; For a 'b' pos_range = 2046, neg_range = -2048 giving (-2040->2048).
;; For a 'b<cond>' pos_range = 254, neg_range = -256 giving (-250 ->256).
(define_insn "cbranchsi4"
[(set (pc)
@ -5552,7 +5567,7 @@
(const_int 4)
(if_then_else
(and (ge (minus (match_dup 3) (pc)) (const_int -2040))
(le (minus (match_dup 3) (pc)) (const_int 2054)))
(le (minus (match_dup 3) (pc)) (const_int 2048)))
(const_int 6)
(const_int 8))))]
)
@ -5583,11 +5598,11 @@
(set (attr "length")
(if_then_else
(and (ge (minus (match_dup 3) (pc)) (const_int -250))
(le (minus (match_dup 3) (pc)) (const_int 254)))
(le (minus (match_dup 3) (pc)) (const_int 256)))
(const_int 4)
(if_then_else
(and (ge (minus (match_dup 3) (pc)) (const_int -2044))
(le (minus (match_dup 3) (pc)) (const_int 2044)))
(and (ge (minus (match_dup 3) (pc)) (const_int -2040))
(le (minus (match_dup 3) (pc)) (const_int 2048)))
(const_int 6)
(const_int 8))))]
)