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/CodeGen/GCStrategy.cpp b/lib/CodeGen/GCStrategy.cpp
index 824cac8..d8c3742 100644
--- a/lib/CodeGen/GCStrategy.cpp
+++ b/lib/CodeGen/GCStrategy.cpp
@@ -19,6 +19,7 @@
#include "llvm/CodeGen/Passes.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
+#include "llvm/Analysis/Dominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -146,6 +147,7 @@
void LowerIntrinsics::getAnalysisUsage(AnalysisUsage &AU) const {
FunctionPass::getAnalysisUsage(AU);
AU.addRequired<GCModuleInfo>();
+ AU.addPreserved<DominatorTree>();
}
/// doInitialization - If this module uses the GC intrinsics, find them now.
@@ -256,9 +258,16 @@
if (NeedsDefaultLoweringPass(S))
MadeChange |= PerformDefaultLowering(F, S);
- if (NeedsCustomLoweringPass(S))
+ bool UseCustomLoweringPass = NeedsCustomLoweringPass(S);
+ if (UseCustomLoweringPass)
MadeChange |= S.performCustomLowering(F);
-
+
+ // Custom lowering may modify the CFG, so dominators must be recomputed.
+ if (UseCustomLoweringPass) {
+ if (DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>())
+ DT->DT->recalculate(F);
+ }
+
return MadeChange;
}