if+return optimizations #209
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| @@ -249,7 +249,7 @@ let private simplifyExpr (didInline: bool ref) env = function | |||
| let sub1 = FunCall(Op "-", [x; a]) | |||
| let sub2 = FunCall(Op "-", [b; a]) | |||
| let div = FunCall(Op "/", [sub1; sub2]) |> mapExpr env | |||
| FunCall(Var (Ident "smoothstep"), [Float (0.M,""); Float (1.M,""); div]) | |||
| FunCall(Var (Ident "smoothstep"), [Float (0.M,""); Float (1.M,""); div]) | |||
src/rewriter.fs
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| | Block b when hasNoDecl b -> b // inline inner empty blocks without variable | ||
| | Decl _ as d -> [Block [d]] // a decl must stay isolated in a block, for the same reason | ||
| | s -> [s] | ||
| List.Cons (If (cond, bodyT, None), bodyF) |
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If (cond, bodyT, None) :: bodyF
| | If (cond, bodyT, Some bodyF) when endsWithReturn bodyT -> | ||
| let bodyF = match bodyF with | ||
| | Block b when hasNoDecl b -> b // inline inner empty blocks without variable | ||
| | Decl _ as d -> [Block [d]] // a decl must stay isolated in a block, for the same reason |
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This shouldn't happen, the variable would be unused.
(I would just remove the line)
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Not if its initialization has side effects
| // if(a)return b;return c; -> return a?b:c; | ||
| let rec replaceIfReturnsByReturnTernary = function | ||
| | If (cond, Jump(JumpKeyword.Return, Some retT), None) :: Jump(JumpKeyword.Return, Some retF) :: c -> | ||
| [Jump(JumpKeyword.Return, Some (FunCall(Op "?:", [cond; retT; retF])))] |
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Optimization idea:
if (c) return a;
x=y;
return z;could be turned into:
return c?a:x=y,z;Note that the transformation should work better after calling groupDeclarations.
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Ah, yes, looks like this isn't already working, because we are so conservative on when to use commas, because of compressed size again I suppose.
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I mean, if we were using squeezeBlockWithComma everywhere, rather than only when it saves some braces, it would already work.
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You'd need to run squeezeBlockWithComma on a subset of the block. You can do it, but it will make the minified output even less readable (unless you also update the Printer).
# Conflicts: # tests/compression_results.log # tests/unit/inline-aggro.aggro.expected # tests/unit/inline-aggro.expected
| let b = removeUselessElseAfterReturn b | ||
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| // if(a)return b;return c; -> return a?b:c; | ||
| let rec replaceIfReturnsByReturnTernary = function |
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replaceIfReturnsWithReturnTernary
replace... with
Needs tests, README update, and preferably a better solution for subtle optimization ordering issues.