PNaCl: Fix ExpandTls to handle a couple of corner cases involving PHI nodes

ExpandTls's use of replaceUsesOfWith() didn't work for PHI nodes
containing the same Constant twice (which needs to work for same or
differing incoming BasicBlocks).  The same applies to
ExpandTlsConstantExpr.

I noticed this while implementing ExpandConstantExpr.

Fix this and factor out some common code that all three passes can
use.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=2837
TEST=test/Transforms/NaCl/*.ll

Review URL: https://codereview.chromium.org/13128002

1 files changed, 6 insertions, 0 deletions

diff --git a/include/llvm/Transforms/NaCl.h b/include/llvm/Transforms/NaCl.h
index 58166bbf22..0a857653ba 100644
--- a/include/llvm/Transforms/NaCl.h
+++ b/include/llvm/Transforms/NaCl.h
@@ -14,7 +14,10 @@ namespace llvm {
 
 class BasicBlockPass;
 class FunctionPass;
+class Instruction;
 class ModulePass;
+class Use;
+class Value;
 
 FunctionPass *createExpandConstantExprPass();
 ModulePass *createExpandCtorsPass();
@@ -26,6 +29,9 @@ ModulePass *createGlobalCleanupPass();
 ModulePass *createResolveAliasesPass();
 ModulePass *createStripMetadataPass();
 
+Instruction *PhiSafeInsertPt(Use *U);
+void PhiSafeReplaceUses(Use *U, Value *NewVal);
+
 }
 
 #endif