LLVM default -mcpu setting inhibits customization
With GHC 8.4.1 we are now passing a default -mcpu
selection to llvm. This default is passed regardless of any explicit command line option such as -optlc=-mcpu=native
. If/when the user explicitly specifies the architecture we now get a failed build. The error message from LLVM is:
llc: for the -mcpu option: may only occur zero or one times!
`llc' failed in phase `LLVM Compiler'. (Exit code: 1)
This is when compiling with GHC 8.4.1 as such:
{{{ ghc-8.4.1 -fforce-recomp -fllvm -optlc=-mcpu=native -O2 tt.hs }}
I suggest we either check for a user option of mcpu
before adding the default or revert this behavior and allow llvm to take it's (optimistic and less portable) default.
Trac metadata
Trac field | Value |
---|---|
Version | 8.4.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (LLVM) |
Test case | |
Differential revisions | |
BlockedBy | |
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Blocking | |
CC | |
Operating system | |
Architecture |