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| author | Dominic Steinitz <dominic@steinitz.org> | 2017-03-07 09:26:16 -0500 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2017-03-07 13:32:33 -0500 |
| commit | 12ccf767af3373e319b75d5d61fe79df4a389e45 (patch) | |
| tree | ec4bf27785be88d67617ddddd5968e4c128fb6a1 /compiler/cmm | |
| parent | 48759c0ef0e7ce718b52557599ebbb884c19a2ad (diff) | |
| download | haskell-12ccf767af3373e319b75d5d61fe79df4a389e45.tar.gz | |
Generate better fp abs for X86 and llvm with default cmm otherwise
Currently we have this in libraries/base/GHC/Float.hs:
```
abs x | x == 0 = 0 -- handles (-0.0)
| x > 0 = x
| otherwise = negateFloat x
```
But 3-4 years ago it was noted that this was inefficient:
https://mail.haskell.org/pipermail/libraries/2013-April/019690.html
We can generate better code for X86 and llvm and for others generate
some custom cmm code which is similar to what the compiler generates
now.
Reviewers: austin, simonmar, hvr, bgamari
Reviewed By: bgamari
Subscribers: dfeuer, thomie
Differential Revision: https://phabricator.haskell.org/D3265
Diffstat (limited to 'compiler/cmm')
| -rw-r--r-- | compiler/cmm/CmmMachOp.hs | 2 | ||||
| -rw-r--r-- | compiler/cmm/PprC.hs | 2 |
2 files changed, 4 insertions, 0 deletions
diff --git a/compiler/cmm/CmmMachOp.hs b/compiler/cmm/CmmMachOp.hs index a8cbd682e6..d736f14bfc 100644 --- a/compiler/cmm/CmmMachOp.hs +++ b/compiler/cmm/CmmMachOp.hs @@ -528,6 +528,7 @@ data CallishMachOp | MO_F64_Atan | MO_F64_Log | MO_F64_Exp + | MO_F64_Fabs | MO_F64_Sqrt | MO_F32_Pwr | MO_F32_Sin @@ -541,6 +542,7 @@ data CallishMachOp | MO_F32_Atan | MO_F32_Log | MO_F32_Exp + | MO_F32_Fabs | MO_F32_Sqrt | MO_UF_Conv Width diff --git a/compiler/cmm/PprC.hs b/compiler/cmm/PprC.hs index dba8ca6e8c..6a84e30abb 100644 --- a/compiler/cmm/PprC.hs +++ b/compiler/cmm/PprC.hs @@ -754,6 +754,7 @@ pprCallishMachOp_for_C mop MO_F64_Log -> text "log" MO_F64_Exp -> text "exp" MO_F64_Sqrt -> text "sqrt" + MO_F64_Fabs -> unsupported MO_F32_Pwr -> text "powf" MO_F32_Sin -> text "sinf" MO_F32_Cos -> text "cosf" @@ -767,6 +768,7 @@ pprCallishMachOp_for_C mop MO_F32_Log -> text "logf" MO_F32_Exp -> text "expf" MO_F32_Sqrt -> text "sqrtf" + MO_F32_Fabs -> unsupported MO_WriteBarrier -> text "write_barrier" MO_Memcpy _ -> text "memcpy" MO_Memset _ -> text "memset" |