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| author | Michal Terepeta <michal.terepeta@gmail.com> | 2019-03-30 18:36:36 +0100 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-04-08 14:29:34 -0400 |
| commit | 63b7d5fb9d695dafc243cbf6f9f70b06030c0dea (patch) | |
| tree | 468304a4f8f6083c367a34ccf50142357e6db311 /compiler | |
| parent | 3a38ea4487173f0f8e3693a75d1c5c7d33f12f05 (diff) | |
| download | haskell-63b7d5fb9d695dafc243cbf6f9f70b06030c0dea.tar.gz | |
Generate straightline code for inline array allocation
GHC has an optimization for allocating arrays when the size is
statically known -- it'll generate the code allocating and initializing
the array inline (instead of a call to a procedure from
`rts/PrimOps.cmm`).
However, the generated code uses a loop to do the initialization. Since
we already check that the requested size is small (we check against
`maxInlineAllocSize`), we can generate faster straightline code instead.
This brings about 15% improvement for `newSmallArray#` in my testing and
slightly simplifies the code in GHC.
Signed-off-by: Michal Terepeta <michal.terepeta@gmail.com>
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/codeGen/StgCmmPrim.hs | 16 |
1 files changed, 5 insertions, 11 deletions
diff --git a/compiler/codeGen/StgCmmPrim.hs b/compiler/codeGen/StgCmmPrim.hs index ae73f0af04..4a07c7893e 100644 --- a/compiler/codeGen/StgCmmPrim.hs +++ b/compiler/codeGen/StgCmmPrim.hs @@ -2105,17 +2105,11 @@ doNewArrayOp res_r rep info payload n init = do -- Initialise all elements of the array p <- assignTemp $ cmmOffsetB dflags (CmmReg arr) (hdrSize dflags rep) - for <- newBlockId - emitLabel for - let loopBody = - [ mkStore (CmmReg (CmmLocal p)) init - , mkAssign (CmmLocal p) (cmmOffsetW dflags (CmmReg (CmmLocal p)) 1) - , mkBranch for ] - emit =<< mkCmmIfThen - (cmmULtWord dflags (CmmReg (CmmLocal p)) - (cmmOffsetW dflags (CmmReg arr) - (hdrSizeW dflags rep + n))) - (catAGraphs loopBody) + let initialization = + [ mkStore (cmmOffsetW dflags (CmmReg (CmmLocal p)) off) init + | off <- [0.. n - 1] + ] + emit (catAGraphs initialization) emit $ mkAssign (CmmLocal res_r) (CmmReg arr) |