Don't merge tiny functions.
It's silly to merge functions like these:
define void @foo(i32 %x) {
ret void
}
define void @bar(i32 %x) {
ret void
}
to get
define void @bar(i32) {
tail call void @foo(i32 %0)
ret void
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191786 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/MergeFunctions.cpp b/lib/Transforms/IPO/MergeFunctions.cpp
index 0f09b90..7e4c1668 100644
--- a/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/lib/Transforms/IPO/MergeFunctions.cpp
@@ -836,6 +836,18 @@
const ComparableFunction &OldF = *Result.first;
+ // Don't merge tiny functions, since it can just end up making the function
+ // larger.
+ // FIXME: Should still merge them if they are unnamed_addr and produce an
+ // alias.
+ if (NewF.getFunc()->size() == 1) {
+ if (NewF.getFunc()->front().size() <= 2) {
+ DEBUG(dbgs() << NewF.getFunc()->getName()
+ << " is to small to bother merging\n");
+ return false;
+ }
+ }
+
// Never thunk a strong function to a weak function.
assert(!OldF.getFunc()->mayBeOverridden() ||
NewF.getFunc()->mayBeOverridden());