Dragonegg and llvm-gcc self-host broken by miscompile of llvm-tblgen

These self-host builders all just starting failing. It looks like tablegen is
being miscompiled.

The first failed builds:
(1) http://lab.llvm.org:8011/builders/llvm-gcc-i386-linux-selfhost/builds/208
(2) http://lab.llvm.org:8011/builders/dragonegg-i386-linux/builds/194
(3) http://lab.llvm.org:8011/builders/dragonegg-x86_64-linux/builds/197

The odd thing is that I can't see any suspicious looking commits. Does anyone
have any suggestions?

Here are what the failures look like:

(1)

llvm[1]: Building Intrinsics.gen.tmp from Intrinsics.td
0 llvm-tblgen 0x0818937b
Stack dump:
0. Program arguments: /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.obj.2/Release+Asserts/bin/llvm-tblgen -I /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.src/lib/VMCore -I /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.src/include -I /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.src/include -I /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.src/lib/Target /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.src/include/llvm/Intrinsics.td -o /home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.obj.2/lib/VMCore/Release+Asserts/Intrinsics.gen.tmp -gen-intrinsic
make[1]: *** [/home/baldrick/osuosl/slave/llvm-gcc-i386-linux-selfhost/llvm.obj.2/lib/VMCore/Release+Asserts/Intrinsics.gen.tmp] Segmentation fault

(2)

llvm[1]: Building Intrinsics.gen.tmp from Intrinsics.td
Included from /home/baldrick/osuosl/slave/dragonegg-i386-linux/llvm.src/include/llvm/Intrinsics.td:14:
/home/baldrick/osuosl/slave/dragonegg-i386-linux/llvm.src/include/llvm/CodeGen/ValueTypes.td:18:3: error: expected ';' after declaration
   int Size = size;
   ^

(3)

llvm[1]: Building Intrinsics.gen.tmp from Intrinsics.td
Included from /home/baldrick/osuosl/slave/dragonegg-x86_64-linux/llvm.src/include/llvm/Intrinsics.td:14:
/home/baldrick/osuosl/slave/dragonegg-x86_64-linux/llvm.src/include/llvm/CodeGen/ValueTypes.td:18:14: error: Expected a class name, got 'size'
   int Size = size;
              ^
*** glibc detected *** /home/baldrick/osuosl/slave/dragonegg-x86_64-linux/llvm-build-1/Release+Debug+Asserts/bin/llvm-tblgen: double free or corruption (fasttop): 0x00000000007b11f0 ***

Ciao, Duncan.