[llvm-commits] [llvm] r135333 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolutionExpander.h lib/Analysis/ScalarEvolutionExpander.cpp

[Andrew Trick]

Author: atrick
Date: Fri Jul 15 19:59:39 2011
New Revision: 135333

URL: http://llvm.org/viewvc/llvm-project?rev=135333&view=rev
Log:
Fix SCEVEXpander to handle arbitrary phi expansion. Includes two
related bug fixes and corresponding assertions for uninitialized data
and missing NULL check. Test cases will be included with the new LFTR.

Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
    llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h?rev=135333&r1=135332&r2=135333&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h Fri Jul 15 19:59:39 2011
@@ -72,8 +72,8 @@
   public:
     /// SCEVExpander - Construct a SCEVExpander in "canonical" mode.
     explicit SCEVExpander(ScalarEvolution &se, const char *name)
-      : SE(se), IVName(name), IVIncInsertLoop(0), CanonicalMode(true),
-        Builder(se.getContext(), TargetFolder(se.TD)) {}
+      : SE(se), IVName(name), IVIncInsertLoop(0), IVIncInsertPos(0),
+        CanonicalMode(true), Builder(se.getContext(), TargetFolder(se.TD)) {}
 
     /// clear - Erase the contents of the InsertedExpressions map so that users
     /// trying to expand the same expression into multiple BasicBlocks or

Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=135333&r1=135332&r2=135333&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Fri Jul 15 19:59:39 2011
@@ -19,6 +19,7 @@
 #include "llvm/LLVMContext.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/ADT/STLExtras.h"
+
 using namespace llvm;
 
 /// ReuseOrCreateCast - Arrange for there to be a cast of V to Ty at IP,
@@ -848,6 +849,8 @@
                                         const Loop *L,
                                         const Type *ExpandTy,
                                         const Type *IntTy) {
+  assert(!IVIncInsertLoop || IVIncInsertPos && "Uninitialized insert position");
+
   // Reuse a previously-inserted PHI, if present.
   for (BasicBlock::iterator I = L->getHeader()->begin();
        PHINode *PN = dyn_cast<PHINode>(I); ++I)
@@ -872,13 +875,15 @@
           // If any of the operands don't dominate the insert position, bail.
           // Addrec operands are always loop-invariant, so this can only happen
           // if there are instructions which haven't been hoisted.
-          for (User::op_iterator OI = IncV->op_begin()+1,
-               OE = IncV->op_end(); OI != OE; ++OI)
-            if (Instruction *OInst = dyn_cast<Instruction>(OI))
-              if (!SE.DT->dominates(OInst, IVIncInsertPos)) {
-                IncV = 0;
-                break;
-              }
+          if (L == IVIncInsertLoop) {
+            for (User::op_iterator OI = IncV->op_begin()+1,
+                   OE = IncV->op_end(); OI != OE; ++OI)
+              if (Instruction *OInst = dyn_cast<Instruction>(OI))
+                if (!SE.DT->dominates(OInst, IVIncInsertPos)) {
+                  IncV = 0;
+                  break;
+                }
+          }
           if (!IncV)
             break;
           // Advance to the next instruction.
@@ -920,6 +925,12 @@
   Value *StartV = expandCodeFor(Normalized->getStart(), ExpandTy,
                                 L->getHeader()->begin());
 
+  // StartV must be hoisted into L's preheader to dominate the new phi.
+  Instruction *StartI = dyn_cast<Instruction>(StartV);
+  assert(!StartI || SE.DT->properlyDominates(StartI->getParent(),
+                                             L->getHeader()) && "");
+  (void)StartI;
+
   // Expand code for the step value. Insert instructions right before the
   // terminator corresponding to the back-edge. Do this before creating the PHI
   // so that PHI reuse code doesn't see an incomplete PHI. If the stride is