b1b737ed6c
Enable this in CS for PowerPC; disable it for all other machines. PowerPC has no remainder instruction; the back end uses division to compute remainder. If CS finds both a / b and a % b, then CS now rewrites a % b as a - b * (a / b) and computes a / b only once. This removes an extra division in the PowerPC code, so it saves both time and space. I have not considered whether to enable this optimization for other machines. It might be less useful in machines with a remainder instruction. Also, if a % b occurs before a / b, the EM code gets a DUP. PowerPC ncg handles this DUP well; other back ends might not.
102 lines
2.8 KiB
Plaintext
102 lines
2.8 KiB
Plaintext
wordsize: 2
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pointersize: 2
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%%RA
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general registers: 2
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address registers: 0
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floating point registers: 0
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use general as pointer: yes
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register score parameters:
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local variable:
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(2 cases)
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pointer,general
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(1 size)
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default -> (8,4)
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general,general
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(1 size)
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default -> (4,2)
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address of local variable:
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(2 cases)
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pointer,general
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(1 size)
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default -> (0,0)
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general,general
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(1 size)
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default -> (2,2)
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constant:
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(1 sizes)
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default -> (2,2)
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double constant:
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(1 size)
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default -> (-1,-1)
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address of global variable:
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(1 size)
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default -> (4,2)
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address of procedure:
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(1 size)
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default -> (2,2)
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opening cost parameters:
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local variable:
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(2 cases)
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pointer
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(1 size)
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default -> (9,4)
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general
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(1 size)
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default -> (9,4)
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address of local variable:
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(2 cases)
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pointer
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(1 size)
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default -> (10,6)
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general
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(1 size)
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general -> (10,6)
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constant:
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(1 size)
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default -> (4,4)
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double constant:
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(1 size)
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default -> (1000,1000)
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address of global variable:
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(1 size)
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default -> (4,4)
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address of procedure:
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(1 size)
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default -> (4,4)
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register save costs:
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(4 cases)
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0 -> (0,0)
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1 -> (18,2)
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2 -> (36,4)
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0 -> (0,0)
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%%UD
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access costs of global variables:
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(1 size)
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default -> (4,2)
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access costs of local variables:
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(1 size)
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default -> (4,2)
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%%SR
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overflow harmful?: no
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array bound harmful?: no
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reduce sli if shift count larger than: 0
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%%CS
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#include "em_mnem.h"
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first time then space:
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addressing modes: op_adp op_lof op_ldf op_loi op_dch op_lpb -1
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op_adp op_lof op_ldf op_loi op_dch op_lpb -1
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cheap operations: op_cii op_cui op_ciu op_cuu -1
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op_cii op_cui op_ciu op_cuu -1
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lexical tresholds: 1 1
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indirection limit: 8
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convert remainder to division?: no no
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do not eliminate sli if index on shiftcounts: -1
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-1
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forbidden operators: -1 -1
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%%SP
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global stack pollution allowed?: no
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