[PATCH] [GlobalMerge] Take into account minsize attribute of global users' parents.

[Quentin Colombet]

REPOSITORY
  rL LLVM

================
Comment at: lib/CodeGen/GlobalMerge.cpp:201
@@ -193,3 +200,3 @@
   // If we want to just blindly group all globals together, do so.
   if (!GlobalMergeGroupByUse) {
     BitVector AllGlobals(Globals.size());
----------------
Shouldn’t the size option affect this setting?

================
Comment at: lib/Target/ARM/ARMTargetMachine.cpp:350
@@ -349,2 +349,3 @@
     // tricky when doing code gen per function.
-    addPass(createGlobalMergePass(TM, 127));
+    bool OnlyOptimizeForSize = TM->getOptLevel() < CodeGenOpt::Aggressive;
+    addPass(createGlobalMergePass(TM, 127, OnlyOptimizeForSize));
----------------
Just for the record, a quick comment.

I am not very fond of the “if not aggressive” then do size only, but based of our offline discussion I agree this is pretty much what we do in the pass manager when creating other passes (like loop unswitch).

Anyhow, I do not have a better alternative.


================
Comment at: test/CodeGen/AArch64/global-merge-ignore-single-use-minsize.ll:39
@@ +38,2 @@
+; CHECK-DAG: .zerofill __DATA,__bss,_m2,4,2
+; CHECK-DAG: .zerofill __DATA,__bss,_n2,4,2
----------------
In the previous test case, you have a clear separation between the globals used in minsize functions and the ones used in non-minsize function.

Could you make another test case that mixes both?
I.e.,
G1
G2
G3

minsizefunc {
G1
G3
}

non-minsizefunc {
G1
G2
}

http://reviews.llvm.org/D10054

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