#1852: -O2 -funbox-strict-fields causes incorrect behavior
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Reporter: mwolak | Owner: simonmar
Type: bug | Status: new
Priority: high | Milestone: 6.8.2
Component: Compiler | Version: 6.8.1
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: x86_64 (amd64)
Os: Linux |
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Changes (by simonpj):
* priority: normal => high
* difficulty: => Unknown
* owner: => simonmar
* milestone: => 6.8.2
Comment:
More information: this bug happens
* on a 64-bit machine
* only with `-fasm` not `-fvia-C`
I'm pretty certain it's a bug in the layout of static data constructors.
Here is the assembly code for the static closure for `(Vec 1.0 2.0 3.0
4.0)` (at least I think so). Notice that we're only allocating 4 bytes
per (unboxed) float, whereas we should be allocating 8. Over to you,
Simon.
{{{
rQP_closure:
.quad Main_Vec4_static_info
.byte 0
.byte 0
.byte 128
.byte 63
.byte 0
.byte 0
.byte 0
.byte 64
.byte 0
.byte 0
.byte 64
.byte 64
.byte 0
.byte 0
.byte 128
.byte 64
}}}
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Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1852#comment:1>
GHC <http://www.haskell.org/ghc/>
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