Tail duplication still needs to iterate. Duplicating new instructions onto
the tail of a block may make that block a new candidate for duplication.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89264 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index af5fbd1..871d6dc 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -197,7 +197,6 @@
MadeChange |= OptimizeImpDefsBlock(MBB);
}
-
bool MadeChangeThisIteration = true;
while (MadeChangeThisIteration) {
MadeChangeThisIteration = false;
@@ -206,10 +205,15 @@
MadeChange |= MadeChangeThisIteration;
}
- // Do tail duplication once after tail merging is done. Otherwise it is
+ // Do tail duplication after tail merging is done. Otherwise it is
// tough to avoid situations where tail duplication and tail merging undo
// each other's transformations ad infinitum.
- MadeChange |= TailDuplicateBlocks(MF);
+ MadeChangeThisIteration = true;
+ while (MadeChangeThisIteration) {
+ MadeChangeThisIteration = false;
+ MadeChangeThisIteration |= TailDuplicateBlocks(MF);
+ MadeChange |= MadeChangeThisIteration;
+ }
// See if any jump tables have become mergable or dead as the code generator
// did its thing.