[llvm-commits] [polly] r144278 - /polly/trunk/lib/Analysis/ScopDetection.cpp

[Tobias Grosser]

Author: grosser
Date: Thu Nov 10 06:44:50 2011
New Revision: 144278

URL: http://llvm.org/viewvc/llvm-project?rev=144278&view=rev
Log:
ScopDetect: Use getPointerBase to get the base pointer

Previously we allowed in access functions only a single SCEVUnknown, which later
became the base address. We now use getPointerBase() to derive the base address
and all remaining unknowns are handled as parameters. This allows us to handle
cases like A[b+c];

Modified:
    polly/trunk/lib/Analysis/ScopDetection.cpp

Modified: polly/trunk/lib/Analysis/ScopDetection.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopDetection.cpp?rev=144278&r1=144277&r2=144278&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopDetection.cpp (original)
+++ polly/trunk/lib/Analysis/ScopDetection.cpp Thu Nov 10 06:44:50 2011
@@ -56,6 +56,7 @@
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/RegionIterator.h"
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Assembly/Writer.h"
 
@@ -213,10 +214,26 @@
                                         DetectionContext &Context) const {
   Value *Ptr = getPointerOperand(Inst), *BasePtr;
   const SCEV *AccessFunction = SE->getSCEV(Ptr);
+  const SCEVUnknown *BasePointer;
+  const Value *BaseValue;
 
-  if (!isAffineExpr(&Context.CurRegion, AccessFunction, *SE, &BasePtr))
+  BasePointer = dyn_cast<SCEVUnknown>(SE->getPointerBase(AccessFunction));
+
+  if (!BasePointer)
+    INVALID(AffFunc, "No base pointer");
+
+  BaseValue = BasePointer->getValue();
+
+  if (isa<UndefValue>(BaseValue))
+    INVALID(AffFunc, "Undefined base pointer");
+
+  AccessFunction = SE->getMinusSCEV(AccessFunction, BasePointer);
+
+  if (!isAffineExpr(&Context.CurRegion, AccessFunction, *SE))
     INVALID(AffFunc, "Bad memory address " << *AccessFunction);
 
+  BasePtr = BasePointer->getValue();
+
   // FIXME: Alias Analysis thinks IntToPtrInst aliases with alloca instructions
   // created by IndependentBlocks Pass.
   if (isa<IntToPtrInst>(BasePtr))