Make more passes preserve dominators (or state that they preserve dominators if
they all ready do). This removes two dominator recomputations prior to isel,
which is a 1% improvement in total llc time for 403.gcc.
The only potentially suspect thing is making GCStrategy recompute dominators if
it used a custom lowering strategy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123064 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 4c2bdbc..30e88e9 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -22,6 +22,7 @@
#include "llvm/IntrinsicInst.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ProfileInfo.h"
@@ -401,6 +402,12 @@
PredBB->replaceAllUsesWith(DestBB);
if (P) {
+ DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>();
+ if (DT) {
+ BasicBlock *PredBBIDom = DT->getNode(PredBB)->getIDom()->getBlock();
+ DT->changeImmediateDominator(DestBB, PredBBIDom);
+ DT->eraseNode(PredBB);
+ }
ProfileInfo *PI = P->getAnalysisIfAvailable<ProfileInfo>();
if (PI) {
PI->replaceAllUses(PredBB, DestBB);