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| author | Artem Pyanykh <artem.pyanykh@gmail.com> | 2019-04-04 13:43:38 +0300 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2019-04-09 10:30:13 -0400 |
| commit | af4cea7f1411e5b99e2417d7c2d3d0e697093103 (patch) | |
| tree | ec9ef85347e5c8915e864573997c15aaa8cc5a73 /compiler/utils | |
| parent | 36d380475d9056fdf93305985be3def00aaf6cf7 (diff) | |
| download | haskell-af4cea7f1411e5b99e2417d7c2d3d0e697093103.tar.gz | |
codegen: fix memset unroll for small bytearrays, add 64-bit sets
Fixes #16052
When the offset in `setByteArray#` is statically known, we can provide
better alignment guarantees then just 1 byte.
Also, memset can now do 64-bit wide sets.
The current memset intrinsic is not optimal however and can be
improved for the case when we know that we deal with
(baseAddress at known alignment) + offset
For instance, on 64-bit
`setByteArray# s 1# 23# 0#`
given that bytearray is 8 bytes aligned could be unrolled into
`movb, movw, movl, movq, movq`; but currently it is
`movb x23` since alignment of 1 is all we can embed into MO_Memset op.
Diffstat (limited to 'compiler/utils')
| -rw-r--r-- | compiler/utils/Util.hs | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/compiler/utils/Util.hs b/compiler/utils/Util.hs index 9e67a43bf5..6f7a9e5d07 100644 --- a/compiler/utils/Util.hs +++ b/compiler/utils/Util.hs @@ -87,6 +87,7 @@ module Util ( -- * Integers exactLog2, + byteAlignment, -- * Floating point readRational, @@ -1149,6 +1150,15 @@ exactLog2 x pow2 x | x == 1 = 0 | otherwise = 1 + pow2 (x `shiftR` 1) +-- x is aligned at N bytes means the remainder from x / N is zero. +-- Currently, interested in N <= 8, but can be expanded to N <= 16 or +-- N <= 32 if used within SSE or AVX context. +byteAlignment :: Integer -> Integer +byteAlignment x = case x .&. 7 of + 0 -> 8 + 4 -> 4 + 2 -> 2 + _ -> 1 {- -- ----------------------------------------------------------------------------- |