[Llvm-bgq-discuss] clang ICE: std::atomic<uint_fast16_t>

[Michael Blocksome]

I recently learned that I should not be using types such as 'uint32_t' for 
atomics, but instead should use the "fast" versions of these types, such 
as 'uint_fast32_t'. However, when I use these "fast" types with clang and 
the std::atomic::operator= overload I get a nasty ICE.

I get the same ICE with 'uint64_t', so I'm guessing that 'uint_fast*_t' is 
a typedef to 'uint64_t'...

----

$> cat atomic_store.cc

#include <atomic>

int main ()
{
  // this works fine ...
  std::atomic<uint_fast16_t> a(0);
  a++;

  std::atomic<uint_fast16_t> b;
  b = 0; // fail

  std::atomic<uint16_t> c;
  c = 0; // success

  std::atomic<uint32_t> d;
  d = 0; // success
 
  std::atomic<uint64_t> e;
  e = 0; // fail

  std::atomic<uint_fast32_t> f;
  f = 0; // fail

  return 0;
};

$> /bghome/blocksom/development/c++11/bgclang++ -ferror-limit=10 -I 
/bghome/blocksom/development/c++11/install/libc++/include -std=c++11 
-stdlib=libc++ -g -c atomic_store.cc -o atomic_store.o
fatal error: error in backend: Cannot select: 0x10005b64a80: ch = 
AtomicStore 0x10005b67ac0, 0x10005b66ca0, 0x10005b679c0<Volatile 
ST8[%__a_.i.i62]> [ID=10]
 dbg:/bghome/blocksom/development/c++11/install/libc++/include/atomic:571
  0x10005b66ca0: i64,ch = CopyFromReg 0x10005ac0660, 0x10005b60c30 [ID=8] 
dbg:/bghome/blocksom/development/c++11/install/libc++/include/atomic:571
    0x10005b60c30: i64 = Register %vreg1 [ID=5]
  0x10005b679c0: i64,ch = load 0x10005ac0660, 0x10005b65390, 
0x10005b61230<LD8[%.atomictmp.i.i57]> [ORD=98] [ID=7] 
dbg:/bghome/blocksom/development/c++11/install/libc++/include/atomic:571
    0x10005b65390: i64 = FrameIndex<14> [ORD=98] [ID=1]
    0x10005b61230: i64 = undef [ORD=98] [ID=2]
In function: main
clang: error: clang frontend command failed with exit code 70 (use -v to 
see invocation)
clang version 3.3 (trunk 170456)
Target: powerpc64-bgq-linux
Thread model: posix
clang: note: diagnostic msg: PLEASE submit a bug report to 
http://llvm.org/bugs/ and include the crash backtrace, preprocessed 
source, and associated run script.
clang: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/atomic_store-j00aLw.cpp
clang: note: diagnostic msg: /tmp/atomic_store-j00aLw.sh
clang: note: diagnostic msg: 

********************

Any ideas?


--> http://en.cppreference.com/w/c/types/integer
--> http://en.cppreference.com/w/cpp/atomic/atomic/operator%3D

Thanks,

Michael Blocksome
Blue Gene Messaging
blocksom at us.ibm.com
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