Revert commits related to stack warning.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183579 91177308-0d34-0410-b5e6-96231b3b80d8
Disallow i64 div/rem in PPC32 counter loops

On PPC32, [su]div,rem on i64 types are transformed into runtime library
function calls. As a result, they are not allowed in counter-based loops (the
counter-loops verification pass caught this error; this change fixes PR16169).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183581 91177308-0d34-0410-b5e6-96231b3b80d8
  Fix an assertion in MemCpyOpt pass.

  The MemCpyOpt pass is capable of optimizing:
      callee(&S); copy N bytes from S to D.
    into:
      callee(&D);
subject to some legality constraints. 

  Assertion is triggered when the compiler tries to evalute "sizeof(typeof(D))",
while D is an opaque-typed, 'sret' formal argument of function being compiled.
i.e. the signature of the func being compiled is something like this:
  T caller(...,%opaque* noalias nocapture sret %D, ...)

  The fix is that when come across such situation, instead of calling some
utility functions to get the size of D's type (which will crash), we simply
assume D has at least N bytes as implified by the copy-instruction.

rdar://14073661 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183584 91177308-0d34-0410-b5e6-96231b3b80d8
Add missing zextloadi1 to i64 patterns. PR16721.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183587 91177308-0d34-0410-b5e6-96231b3b80d8