[llvm-commits] [llvm] r51082 - /llvm/trunk/lib/Transforms/Scalar/GVN.cpp

[Owen Anderson]

Author: resistor
Date: Tue May 13 18:18:30 2008
New Revision: 51082

URL: http://llvm.org/viewvc/llvm-project?rev=51082&view=rev
Log:
Fix Analysis/BasicAA/pure-const-dce.ll.  This turned out to be a correctness
bug as well as a missed optimization.  We weren't properly checking for local
dependencies before moving on to non-local ones when doing non-local read-only 
call CSE.

Modified:
    llvm/trunk/lib/Transforms/Scalar/GVN.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=51082&r1=51081&r2=51082&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Tue May 13 18:18:30 2008
@@ -441,6 +441,43 @@
         return nextValueNumber++;
       }
       
+      Instruction* local_dep = MD->getDependency(C);
+      
+      if (local_dep == MemoryDependenceAnalysis::None) {
+        valueNumbering.insert(std::make_pair(V, nextValueNumber));
+        return nextValueNumber++;
+      } else if (local_dep != MemoryDependenceAnalysis::NonLocal) {
+        if (!isa<CallInst>(local_dep)) {
+          valueNumbering.insert(std::make_pair(V, nextValueNumber));
+          return nextValueNumber++;
+        }
+        
+        CallInst* local_cdep = cast<CallInst>(local_dep);
+        
+        if (local_cdep->getCalledFunction() != C->getCalledFunction() ||
+            local_cdep->getNumOperands() != C->getNumOperands()) {
+          valueNumbering.insert(std::make_pair(V, nextValueNumber));
+          return nextValueNumber++;
+        } else if (!C->getCalledFunction()) { 
+          valueNumbering.insert(std::make_pair(V, nextValueNumber));
+          return nextValueNumber++;
+        } else {
+          for (unsigned i = 1; i < C->getNumOperands(); ++i) {
+            uint32_t c_vn = lookup_or_add(C->getOperand(i));
+            uint32_t cd_vn = lookup_or_add(local_cdep->getOperand(i));
+            if (c_vn != cd_vn) {
+              valueNumbering.insert(std::make_pair(V, nextValueNumber));
+              return nextValueNumber++;
+            }
+          }
+        
+          uint32_t v = lookup_or_add(local_cdep);
+          valueNumbering.insert(std::make_pair(V, v));
+          return v;
+        }
+      }
+      
+      
       DenseMap<BasicBlock*, Value*> deps;
       MD->getNonLocalDependency(C, deps);
       CallInst* cdep = 0;
@@ -488,7 +525,7 @@
           }
         }
         
-        uint32_t v = valueNumbering[cdep];
+        uint32_t v = lookup_or_add(cdep);
         valueNumbering.insert(std::make_pair(V, v));
         return v;
       }