| | 1 | (* L2 compiler |
| | 2 | * peephole optimizer |
| | 3 | * optimizes away redundant insns such as: |
| | 4 | mov a, b |
| | 5 | mov a, b |
| | 6 | |
| | 7 | mov a, b |
| | 8 | mov b, a |
| | 9 | |
| | 10 | mov a, a |
| | 11 | |
| | 12 | neg a |
| | 13 | neg a |
| | 14 | * Author: Chris Lu <czl@andrew.cmu.edu> |
| | 15 | *) |
| | 16 | |
| | 17 | signature PEEPHOLE = |
| | 18 | sig |
| | 19 | val peephole : x86.insn list -> x86.insn list |
| | 20 | end |
| | 21 | |
| | 22 | structure Peephole :> PEEPHOLE = |
| | 23 | struct |
| | 24 | structure X = x86 |
| | 25 | |
| | 26 | (* val peephole : x86.insn list -> x86.insn list *) |
| | 27 | |
| | 28 | fun peephole ((insn1 as X.MOVL(a1,b1))::(insn2 as X.MOVL(a2,b2))::l) = |
| | 29 | if(x86.opereq(a1, b1) orelse (x86.opereq(a1, a2) andalso x86.opereq(b1, b2))) then |
| | 30 | peephole (insn2::l) |
| | 31 | else if(x86.opereq(a2, b2) orelse (x86.opereq(a1, b2) andalso x86.opereq(b1, a2))) then |
| | 32 | peephole (insn1::l) |
| | 33 | else |
| | 34 | insn1::(peephole (insn2::l)) |
| | 35 | | peephole ((insn as X.MOVL(a,b))::l) = if x86.opereq(a, b) then peephole l else insn::(peephole l) |
| | 36 | | peephole ((insn1 as X.NEG(a))::(insn2 as X.NEG(b))::l) = if x86.opereq(a, b) then peephole l else insn1::(peephole (insn2::l)) |
| | 37 | | peephole (a::l) = a::(peephole l) |
| | 38 | | peephole nil = nil |
| | 39 | |
| | 40 | end |
git.joshuawise.com / snipe.git / blame_incremental