The pass used to be enabled by default with CodeGenOpt::Less (-O1).
This is too aggressive, considering the pass indiscriminately merges
all globals together.
Currently, performance doesn't always improve, and, on code that uses
few globals (e.g., the odd file- or function- static), more often than
not is degraded by the optimization. Lengthy discussion can be found
on llvmdev (AArch64-focused; ARM has similar problems):
http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-February/082800.html
Also, it makes tooling and debuggers less useful when dealing with
globals and data sections.
GlobalMerge needs to better identify those cases that benefit, and this
will be done separately. In the meantime, move the pass to run with
-O3 rather than -O1, on both ARM and AArch64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233024 91177308-0d34-0410-b5e6-96231b3b80d8
It is generally not sufficient to check if the starting offset is in range
of the maximum offset that can be efficiently used for the target.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119565 91177308-0d34-0410-b5e6-96231b3b80d8
This makes it more clear that the symbol is an internal, compiler-generated
name and gives a little more description about its contents.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119564 91177308-0d34-0410-b5e6-96231b3b80d8
It was mistakenly looking at the pointer type when checking for the size of
global variables. This is a partial fix for Radar 8673120.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119563 91177308-0d34-0410-b5e6-96231b3b80d8
