Large let bindings are 6x slower (since 6.12.x to 7.10.x)
See the attached somewhat reduced version of the main (manually unrolled) portion of an MD5 implementation taken from PureMD5. It used to compile in about 200ms, which is already bad enough, but now takes 1200 ms (ghc 6.12.3 to ghc 7.10.3 using -O2). I'd like to note that in my light testing the UNPACK pragma accounts for 400ms of this delta.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.10.3 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
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| Operating system | |
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