1 files changed, 40 insertions, 0 deletions
diff --git a/lib/Transforms/NaCl/ExpandUtils.cpp b/lib/Transforms/NaCl/ExpandUtils.cpp
new file mode 100644
index 0000000000..0670ff75ce
--- /dev/null
+++ b/lib/Transforms/NaCl/ExpandUtils.cpp
@@ -0,0 +1,40 @@
+//===-- ExpandUtils.cpp - Helper functions for expansion passes -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/Transforms/NaCl.h"
+
+using namespace llvm;
+
+Instruction *llvm::PhiSafeInsertPt(Use *U) {
+  Instruction *InsertPt = cast<Instruction>(U->getUser());
+  if (PHINode *PN = dyn_cast<PHINode>(InsertPt)) {
+    // We cannot insert instructions before a PHI node, so insert
+    // before the incoming block's terminator.  This could be
+    // suboptimal if the terminator is a conditional.
+    InsertPt = PN->getIncomingBlock(*U)->getTerminator();
+  }
+  return InsertPt;
+}
+
+void llvm::PhiSafeReplaceUses(Use *U, Value *NewVal) {
+  if (PHINode *PN = dyn_cast<PHINode>(U->getUser())) {
+    // A PHI node can have multiple incoming edges from the same
+    // block, in which case all these edges must have the same
+    // incoming value.
+    BasicBlock *BB = PN->getIncomingBlock(*U);
+    for (unsigned I = 0; I < PN->getNumIncomingValues(); ++I) {
+      if (PN->getIncomingBlock(I) == BB)
+        PN->setIncomingValue(I, NewVal);
+    }
+  } else {
+    U->getUser()->replaceUsesOfWith(U->get(), NewVal);
+  }
+}