[PATCH] D49822: [GlobalMerge] Allow merging globals with explicit section markings.

[Eli Friedman via Phabricator via llvm-commits]

efriedma created this revision.
efriedma added a reviewer: greened.

At least on ELF, it's impossible to tell without disassembling the code whether two globals with the same section marking were merged: the merged global uses "private" linkage to hide its symbol, and the aliases look like regular symbols.  I can't think of any other reason to disallow it. (Of course, we can only merge globals in the same section.)

The weird alignment handling matches AsmPrinter; our alignment handling for global variables should probably be refactored.

This transform is very profitable for one proprietary codebase I've been looking at, which uses a lot of globals with section markings.


Repository:
  rL LLVM

https://reviews.llvm.org/D49822

Files:
  lib/CodeGen/GlobalMerge.cpp
  test/Transforms/GlobalMerge/basic.ll

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