The Trunk: Compiler-eem.317.mcz

Eliot Miranda uploaded a new version of Compiler to project The Trunk:
http://source.squeak.org/trunk/Compiler-eem.317.mcz

==================== Summary ====================

Name: Compiler-eem.317
Author: eem
Time: 21 November 2015, 3:20:26.817 pm
UUID: 956bcba6-bf0a-463c-aaef-90903732fb85
Ancestors: Compiler-nice.316

Small improvement to compiler performance.  There is no need to scan for an assignment to the limit in a to:[by:]do: when the to: argument is known to be an argument, because arguments are not written to.

=============== Diff against Compiler-nice.316 ===============

Item was changed:
  ----- Method: MessageNode>>transformToDo: (in category 'macro transformations') -----
  transformToDo: encoder
  " var := rcvr. L1: [var <= arg1] Bfp(L2) [block body. var := var + inc] Jmp(L1) L2: "
+ | limit increment block initStmt test incStmt limitInit blockVar myRange blockRange |
- | limit increment block initStmt test incStmt limitInit blockVar myRange blockRange limitIsAssignedTo |
  block := arguments last.
  "First check for valid arguments"
  (block notNil
  and: [block isBlockNode
  and: [block numberOfArguments = 1
  and: [block firstArgument isVariableReference "As with debugger remote vars"]]]) ifFalse:
  [^false].
  arguments size = 3
  ifTrue: [increment := arguments at: 2.
  (increment isConstantNumber
  and: [increment literalValue ~= 0]) ifFalse: [^false]]
  ifFalse: [increment := encoder encodeLiteral: 1].
  (limit := arguments at: 1) isVariableReference ifTrue:
+ [| shouldScanForAssignment |
+ shouldScanForAssignment := limit isArg not
+ or: [limit isBlockArg and: [Scanner allowBlockArgumentAssignment]].
+ shouldScanForAssignment ifTrue:
+ [block nodesDo:
+ [:node|
+ (node isAssignmentNode and: [node variable = limit]) ifTrue:
+ [^false]]]].
- [limitIsAssignedTo := false.
- block nodesDo:
- [:node|
- (node isAssignmentNode and: [node variable = limit]) ifTrue:
- [limitIsAssignedTo := true]].
- limitIsAssignedTo ifTrue:
- [^false]].
  arguments size < 3 ifTrue:   "transform to full form"
  [selector := SelectorNode new key: #to:by:do: code: #macro].
 
  "Now generate auxiliary structures"
  myRange := encoder rawSourceRanges at: self ifAbsent: [1 to: 0].
  blockRange := encoder rawSourceRanges at: block ifAbsent: [1 to: 0].
  blockVar := block firstArgument.
  initStmt := AssignmentNode new variable: blockVar value: receiver.
+ (limit isVariableReference or: [limit isConstantNumber])
- limit isVariableReference | limit isConstantNumber
  ifTrue: [limitInit := nil]
  ifFalse:  "Need to store limit in a var"
  [limit := encoder bindBlockArg: blockVar key, 'LimiT' within: block.
  limit scope: -2.  "Already done parsing block; flag so it won't print"
  block addArgument: limit.
  limitInit := AssignmentNode new
  variable: limit
  value: arguments first].
  test := MessageNode new
  receiver: blockVar
  selector: (increment key > 0 ifTrue: [#<=] ifFalse: [#>=])
  arguments: {limit}
  precedence: precedence
  from: encoder
  sourceRange: (myRange first to: blockRange first).
  incStmt := AssignmentNode new
  variable: blockVar
  value: (MessageNode new
  receiver: blockVar selector: #+
  arguments: {increment}
  precedence: precedence
  from: encoder
  sourceRange: (myRange last to: (myRange last max: blockRange last)))
  from: encoder
  sourceRange: (myRange last to: (myRange last max: blockRange last)).
  arguments := {limit. increment. block. initStmt. test. incStmt. limitInit}.
  block noteOptimizedIn: self.
  ^true!