Minimal LDA interface, maximally conservative tester.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74401 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 29 insertions, 0 deletions

diff --git a/include/llvm/Analysis/LoopDependenceAnalysis.h b/include/llvm/Analysis/LoopDependenceAnalysis.h
index 0c3dadea75..bde426ba9a 100644
--- a/include/llvm/Analysis/LoopDependenceAnalysis.h
+++ b/include/llvm/Analysis/LoopDependenceAnalysis.h
@@ -28,6 +28,7 @@ namespace llvm {
 
   class AnalysisUsage;
   class ScalarEvolution;
+  class Value;
 
   class LoopDependenceAnalysis : public LoopPass {
     Loop *L;
@@ -37,6 +38,10 @@ namespace llvm {
     static char ID; // Class identification, replacement for typeinfo
     LoopDependenceAnalysis() : LoopPass(&ID) {}
 
+    /// TODO: docs
+    bool isDependencePair(const Value*, const Value*) const;
+    bool depends(Value*, Value*);
+
     bool runOnLoop(Loop*, LPPassManager&);
 
     virtual void getAnalysisUsage(AnalysisUsage&) const;
diff --git a/lib/Analysis/LoopDependenceAnalysis.cpp b/lib/Analysis/LoopDependenceAnalysis.cpp
index 8f3e6baf5c..b23459e81a 100644
--- a/lib/Analysis/LoopDependenceAnalysis.cpp
+++ b/lib/Analysis/LoopDependenceAnalysis.cpp
@@ -21,6 +21,7 @@
 #include "llvm/Analysis/LoopDependenceAnalysis.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Instructions.h"
 using namespace llvm;
 
 LoopPass *llvm::createLoopDependenceAnalysisPass() {
@@ -32,6 +33,29 @@ R("lda", "Loop Dependence Analysis", false, true);
 char LoopDependenceAnalysis::ID = 0;
 
 //===----------------------------------------------------------------------===//
+//                             Utility Functions
+//===----------------------------------------------------------------------===//
+
+static inline bool isMemRefInstr(const Value *I) {
+  return isa<LoadInst>(I) || isa<StoreInst>(I);
+}
+
+//===----------------------------------------------------------------------===//
+//                             Dependence Testing
+//===----------------------------------------------------------------------===//
+
+bool LoopDependenceAnalysis::isDependencePair(const Value *x,
+                                              const Value *y) const {
+  return isMemRefInstr(x) && isMemRefInstr(y)
+      && (isa<StoreInst>(x) || isa<StoreInst>(y));
+}
+
+bool LoopDependenceAnalysis::depends(Value *src, Value *dst) {
+  assert(isDependencePair(src, dst) && "Values form no dependence pair!");
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
 //                   LoopDependenceAnalysis Implementation
 //===----------------------------------------------------------------------===//