Temporarily revert D83903 "[PGO] Enable the extended value profile buckets for mem op sizes."

[MaskRay]

Summary

__llvm_profile_instrument_memop transitively calls calloc, thus calloc
should not be instrumented.

I saw a
calloc -> __llvm_profile_instrument_memop -> calloc -> __llvm_profile_instrument_memop -> ...
infinite loop leading to stack overflow
when the malloc implementation (e.g. tcmalloc) is built and instrumented along with the application.

We should figure out the library calls which may be instrumented and disable
their instrumentation before rolling out this change.

llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp

cl::opt<unsigned> MemOPSizeLarge(
     cl::desc("Set large value thresthold in memory intrinsic size profiling. "
              "Value of 0 disables the large value profiling."),
     cl::init(8192));
 
 cl::opt<bool> UseOldMemOpValueProf(
     "use-old-memop-value-prof",
     cl::desc("Use the old memop value profiling buckets. This is "
              "transitional and to be removed after switching. "),
-    cl::init(false));
+    cl::init(true));
 
 namespace {
 
 cl::opt<bool> DoHashBasedCounterSplit(
     "hash-based-counter-split",
     cl::desc("Rename counter variable of a comdat function based on cfg hash"),
     cl::init(true));