[GlobalMerge] Take into account minsize on Global users' parents.

Now that we can look at users, we can trivially do this: when we would
have otherwise disabled GlobalMerge (currently -O<3), we can just run
it for minsize functions, as it's usually a codesize win.

Differential Revision: http://reviews.llvm.org/D10054

llvm-svn: 239087

1 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/Target/ARM/ARMTargetMachine.cpp b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
index e794fb7..0f98d52 100644
--- a/llvm/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/llvm/lib/Target/ARM/ARMTargetMachine.cpp
@@ -339,15 +339,18 @@ void ARMPassConfig::addIRPasses() {
 }
 
 bool ARMPassConfig::addPreISel() {
-  if ((TM->getOptLevel() == CodeGenOpt::Aggressive &&
+  if ((TM->getOptLevel() != CodeGenOpt::None &&
        EnableGlobalMerge == cl::BOU_UNSET) ||
-      EnableGlobalMerge == cl::BOU_TRUE)
+      EnableGlobalMerge == cl::BOU_TRUE) {
     // FIXME: This is using the thumb1 only constant value for
     // maximal global offset for merging globals. We may want
     // to look into using the old value for non-thumb1 code of
     // 4095 based on the TargetMachine, but this starts to become
     // tricky when doing code gen per function.
-    addPass(createGlobalMergePass(TM, 127));
+    bool OnlyOptimizeForSize = (TM->getOptLevel() < CodeGenOpt::Aggressive) &&
+                               (EnableGlobalMerge == cl::BOU_UNSET);
+    addPass(createGlobalMergePass(TM, 127, OnlyOptimizeForSize));
+  }
 
   return false;
 }