Safe Haskell	None
Language	Haskell2010

Futhark.Optimise.CSE

Description

This module implements common-subexpression elimination. This module does not actually remove the duplicate, but only replaces one with a diference to the other. E.g:

  let a = x + y
  let b = x + y

becomes:

  let a = x + y
  let b = a

After which copy propagation in the simplifier will actually remove the definition of b.

Our CSE is still rather stupid. No normalisation is performed, so the expressions x+y and y+x will be considered distinct. Furthermore, no expression with its own binding will be considered equal to any other, since the variable names will be distinct. This affects SOACs in particular.

Synopsis

performCSE :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> Pass lore lore
performCSEOnFunDef :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> FunDef lore -> FunDef lore
performCSEOnStms :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> Stms lore -> Stms lore
class CSEInOp op

Documentation

performCSE :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> Pass lore lore Source #

Perform CSE on every function in a program.

If the boolean argument is false, the pass will not perform CSE on expressions producing arrays. This should be disabled when the lore has memory information, since at that point arrays have identity beyond their value.

performCSEOnFunDef :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> FunDef lore -> FunDef lore Source #

Perform CSE on a single function.

If the boolean argument is false, the pass will not perform CSE on expressions producing arrays. This should be disabled when the lore has memory information, since at that point arrays have identity beyond their value.

performCSEOnStms :: (ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => Bool -> Stms lore -> Stms lore Source #

Perform CSE on some statements.

If the boolean argument is false, the pass will not perform CSE on expressions producing arrays. This should be disabled when the lore has memory information, since at that point arrays have identity beyond their value.

class CSEInOp op Source #

The operations that permit CSE.

Minimal complete definition

cseInOp

Instances

Instances details

CSEInOp () Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: () -> CSEM lore ()
(ASTLore lore, CanBeAliased (Op lore), CSEInOp (OpWithAliases (Op lore))) => CSEInOp (SOAC (Aliases lore)) Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: SOAC (Aliases lore) -> CSEM lore0 (SOAC (Aliases lore))
CSEInOp op => CSEInOp (MemOp op) Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: MemOp op -> CSEM lore (MemOp op)
(ASTLore lore, Aliased lore, CSEInOp (Op lore)) => CSEInOp (SegOp lvl lore) Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: SegOp lvl lore -> CSEM lore0 (SegOp lvl lore)
(ASTLore lore, Aliased lore, CSEInOp (Op lore), CSEInOp op) => CSEInOp (MCOp lore op) Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: MCOp lore op -> CSEM lore0 (MCOp lore op)
(ASTLore lore, Aliased lore, CSEInOp (Op lore), CSEInOp op) => CSEInOp (HostOp lore op) Source #
Instance details Defined in Futhark.Optimise.CSE Methods cseInOp :: HostOp lore op -> CSEM lore0 (HostOp lore op)