[GHC] #7575: LLVM backend does not properly widen certain literal types in call expressions

[GHC]

#7575: LLVM backend does not properly widen certain literal types in call
expressions
-------------------------------+--------------------------------------------
Reporter:  thoughtpolice       |          Owner:                  
    Type:  bug                 |         Status:  new             
Priority:  normal              |      Component:  Compiler (LLVM) 
 Version:  7.7                 |       Keywords:  llvm, codegen   
      Os:  Unknown/Multiple    |   Architecture:  Unknown/Multiple
 Failure:  Compile-time crash  |      Blockedby:                  
Blocking:                      |        Related:  #7571, #7574    
-------------------------------+--------------------------------------------

Comment(by thoughtpolice):

 Correction: this test correctly triggers the bug:

 {{{
 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE MagicHash, UnliftedFFITypes #-}
 module T7575 where
 import GHC.Prim
 import GHC.Word
 import GHC.Types

 foreign import ccall unsafe "hs_eqWord64" dummy_eqWord64# :: Word64# ->
 Word64# -> Bool

 check :: Word64 -> Word64 -> Bool
 check (W64# x#) (W64# y#) = dummy_eqWord64# x# y#

 check2 :: Word64 -> Bool
 check2 x = check x 0
 }}}

 Testing vs 7.4.1:

 {{{
  $ ghc --version
 The Glorious Glasgow Haskell Compilation System, version 7.4.1
  $ ghc -c -O2 -fforce-recomp T7575.hs
  $ ~/code/ghc/inplace/bin/ghc-stage1 --version
 The Glorious Glasgow Haskell Compilation System, version 7.7.20130113
  $ ~/code/ghc/inplace/bin/ghc-stage1 -c -O2 -fforce-recomp T7575.hs
 You are using a new version of LLVM that hasn't been tested yet!
 We will try though...
 /home/linaro/bin/opt: /tmp/ghc26188_0/ghc26188_0.ll:594:60: error:
 argument is not of expected type 'i64'
   %lnxh = call ccc i32 (i64,i64)* @hs_eqWord64( i64 %lnxg, i32 0 )
 nounwind
                                                            ^
  $ ~/code/ghc/inplace/bin/ghc-stage1 -c -O2 -fforce-recomp T7575.hs -pgmlo
 opt-3.0 -pgmlc llc-3.0
 opt-3.0: /tmp/ghc26199_0/ghc26199_0.ll:594:60: error: argument is not of
 expected type 'i64'
   %lnxh = call ccc i32 (i64,i64)* @hs_eqWord64( i64 %lnxg, i32 0 )
 nounwind
                                                            ^
  $
 }}}

 So this is definitely a compiler regression in the backend somewhere.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7575#comment:3>
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