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bbaa44a7
by Peng Fan at 2025-07-16T16:50:42-04:00
NCG/LA64: Support finer-grained DBAR hints
For LA664 and newer uarchs, they have made finer granularity hints
available:
Bit4: ordering or completion (0: completion, 1: ordering)
Bit3: barrier for previous read (0: true, 1: false)
Bit2: barrier for previous write (0: true, 1: false)
Bit1: barrier for succeeding read (0: true, 1: false)
Bit0: barrier for succeeding write (0: true, 1: false)
And not affect the existing models because other hints are treated
as 'dbar 0' there.
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7da86e16
by Andreas Klebinger at 2025-07-16T16:51:25-04:00
Disable -fprof-late-overloaded-calls for join points.
Currently GHC considers cost centres as destructive to
join contexts. Or in other words this is not considered valid:
join f x = ...
in
... -> scc<tick> jmp
This makes the functionality of `-fprof-late-overloaded-calls` not feasible
for join points in general. We used to try to work around this by putting the
ticks on the rhs of the join point rather than around the jump. However beyond
the loss of accuracy this was broken for recursive join points as we ended up
with something like:
rec-join f x = scc<tick> ... jmp f x
Which similarly is not valid as the tick once again destroys the tail call.
One might think we could limit ourselves to non-recursive tail calls and do
something clever like:
join f x = scc<tick> ...
in ... jmp f x
And sometimes this works! But sometimes the full rhs would look something like:
join g x = ....
join f x = scc<tick> ... -> jmp g x
Which, would again no longer be valid. I believe in the long run we can make
cost centre ticks non-destructive to join points. Or we could keep track of
where we are/are not allowed to insert a cost centre. But in the short term I will
simply disable the annotation of join calls under this flag.
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93f01d7c
by ARATA Mizuki at 2025-07-16T17:24:27-04:00
x86 NCG: Better lowering for shuffleFloatX4# and shuffleDoubleX2#
The new implementation
* make use of specialized instructions like (V)UNPCK{L,H}{PS,PD}, and
* do not require -mavx.
Close #26096
Co-authored-by: sheaf <sam.derbyshire@gmail.com>
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97654402
by Jappie Klooster at 2025-07-16T17:24:39-04:00
Update interact docs to explain about buffering
We need to tell the user to set to the
appropriate buffer format.
Otherwise, this function may get randomly stuck,
or just behave confusingly.
issue: https://gitlab.haskell.org/ghc/ghc/-/issues/26131
NB, I'm running this with cabal *NOT* ghci. ghci messes with buffering anyway.
```haskell
interaction :: String -> String
interaction "jappie" = "hi"
interaction "jakob" = "hello"
interaction x = "unkown input: " <> x
main :: IO ()
main = interact interaction
```
so in my input (prefixed by `>`) I get:
```
> jappie
unkown input: jappie
```
we confirmed later this was due to lack of \n matching.
Anyway movnig on to more unexpected stuff:
```haskell
main :: IO ()
main = do
interact (concatMap interaction . lines)
```
get's stuck forever.
actually `^D` (ctrl+d) unstucks it and runs all input as expected.
for example you can get:
```
> sdfkds
> fakdsf
unkown input: sdfkdsunkown input: fakdsf
```
This program works!
```haskell
interaction :: String -> String
interaction "jappie" = "hi \n"
interaction "jakob" = "hello \n"
interaction x = "unkown input: " <> x <> "\n"
main :: IO ()
main = do
interact (concatMap interaction . lines)
```
the reason is that linebuffering is set for both in and output by default.
so lines eats the input lines, and all the \n postfixes make sure the buffer
is put out.
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782033f3
by Zubin Duggal at 2025-07-16T17:24:40-04:00
fetch_gitlab: Ensure we copy users_guide.pdf and Haddock.pdf to the release docs directory
Fixes #24093