[llvm-commits] [llvm] r40540 - in /llvm/trunk: lib/Analysis/MemoryDependenceAnalysis.cpp lib/Transforms/Scalar/GVN.cpp test/Transforms/GVN/2007-07-26-InterlockingLoops.ll test/Transforms/GVN/2007-07-26-PhiErasure.ll

Owen Anderson resistor at mac.com
Thu Jul 26 11:26:51 PDT 2007


Author: resistor
Date: Thu Jul 26 13:26:51 2007
New Revision: 40540

URL: http://llvm.org/viewvc/llvm-project?rev=40540&view=rev
Log:
Fix a couple more bugs in the phi construction by pulling in code that does
almost the same things from LCSSA.

Added:
    llvm/trunk/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll
    llvm/trunk/test/Transforms/GVN/2007-07-26-PhiErasure.ll
Modified:
    llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
    llvm/trunk/lib/Transforms/Scalar/GVN.cpp

Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=40540&r1=40539&r2=40540&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Thu Jul 26 13:26:51 2007
@@ -124,9 +124,6 @@
   
   visited.erase(block);
   
-  if (!inserted)
-    resp.insert(std::make_pair(block, None));
-  
   return inserted;
 }
 

Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=40540&r1=40539&r2=40540&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Thu Jul 26 13:26:51 2007
@@ -13,12 +13,14 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "gvn"
-#include "llvm/Value.h"
+
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/BasicBlock.h"
-#include "llvm/Instructions.h"
-#include "llvm/Function.h"
+#include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Value.h"
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/DenseMap.h"
@@ -650,9 +652,8 @@
                             DenseMap<Value*, LoadInst*>& lastSeenLoad,
                             SmallVector<Instruction*, 4>& toErase);
     bool processNonLocalLoad(LoadInst* L, SmallVector<Instruction*, 4>& toErase);
-    Value *performPHIConstruction(BasicBlock *BB, LoadInst* orig,
-                                  DenseMap<BasicBlock*, Value*> &Phis,
-                                  SmallPtrSet<BasicBlock*, 4>& visited);
+    Value *GetValueForBlock(BasicBlock *BB, LoadInst* orig,
+                                  DenseMap<BasicBlock*, Value*> &Phis);
     void dump(DenseMap<BasicBlock*, Value*>& d);
   };
   
@@ -706,59 +707,35 @@
 }
 
 
-Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
-                                   DenseMap<BasicBlock*, Value*> &Phis,
-                                   SmallPtrSet<BasicBlock*, 4>& visited) {
-  DenseMap<BasicBlock*, Value*>::iterator DI = Phis.find(BB);
-  if (DI != Phis.end())
-    return DI->second;
-  
-  unsigned numPreds = std::distance(pred_begin(BB), pred_end(BB));
-  
-  if (numPreds == 1) {
-    DenseMap<BasicBlock*, Value*>::iterator DI = Phis.find(BB);
-    if (DI != Phis.end()) {
-      Phis.insert(std::make_pair(BB, DI->second));
-      return DI->second;
-    } else {
-      visited.insert(BB);
-      Value* domV = performPHIConstruction(*pred_begin(BB), orig, Phis, visited);
-      visited.erase(BB);
-      
-      Phis.insert(std::make_pair(BB, domV));
-      return domV;
-    }
-  } else {
-    PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle", BB->begin());
-    PN->reserveOperandSpace(numPreds);
-    Phis[BB] = PN;
-    
-    visited.insert(BB);
-    // Fill in the incoming values for the block.
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
-      if (!visited.count(*PI))
-        PN->addIncoming(performPHIConstruction(*PI, orig, Phis, visited), *PI);
-      else {
-        if (Phis[*PI])
-          PN->addIncoming(Phis[*PI], *PI);
-        else
-          PN->addIncoming(PN, *PI);
-      }
-    visited.erase(BB);
-    
-    bool all_same = PN->getNumIncomingValues() != 1;
-    Value* first = PN->getIncomingValue(0);
-    for (unsigned i = 1; i < PN->getNumIncomingValues(); ++i)
-      all_same &= (PN->getIncomingValue(i) == first);
-    
-    if (all_same) {
-      PN->eraseFromParent();
-      Phis[BB] = first;
-      return first;
-    } else {
-      return PN;
-    }
+/// GetValueForBlock - Get the value to use within the specified basic block.
+/// available values are in Phis.
+Value *GVN::GetValueForBlock(BasicBlock *BB, LoadInst* orig,
+                               DenseMap<BasicBlock*, Value*> &Phis) {
+  DominatorTree &DT = getAnalysis<DominatorTree>(); 
+                                 
+  // If we have already computed this value, return the previously computed val.
+  Value *&V = Phis[BB];
+  if (V) return V;
+
+  DomTreeNode *IDom = DT.getNode(BB)->getIDom();
+
+  if (IDom && Phis.count(IDom->getBlock())) {
+    return V = GetValueForBlock(IDom->getBlock(), orig, Phis);
   }
+  
+  
+  
+  // Otherwise, the idom is the loop, so we need to insert a PHI node.  Do so
+  // now, then get values to fill in the incoming values for the PHI.
+  PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle",
+                            BB->begin());
+  PN->reserveOperandSpace(std::distance(pred_begin(BB), pred_end(BB)));
+  V = PN;
+                                 
+  // Fill in the incoming values for the block.
+  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
+    PN->addIncoming(GetValueForBlock(DT.getNode(*PI)->getBlock(), orig, Phis), *PI);
+  return PN;
 }
 
 bool GVN::processNonLocalLoad(LoadInst* L, SmallVector<Instruction*, 4>& toErase) {
@@ -789,7 +766,7 @@
     }
   
   SmallPtrSet<BasicBlock*, 4> visited;
-  Value* v = performPHIConstruction(L->getParent(), L, repl, visited);
+  Value* v = GetValueForBlock(L->getParent(), L, repl);
   
   MD.removeInstruction(L);
   L->replaceAllUsesWith(v);

Added: llvm/trunk/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll?rev=40540&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll (added)
+++ llvm/trunk/test/Transforms/GVN/2007-07-26-InterlockingLoops.ll Thu Jul 26 13:26:51 2007
@@ -0,0 +1,30 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep {tmp17625 =}
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep {tmp17631 =}
+
+ at last = external global [65 x i32*]		; <[65 x i32*]*> [#uses=1]
+
+define i32 @NextRootMove(i32 %wtm) {
+cond_next95:		; preds = %cond_true85, %cond_true79, %cond_true73, %bb68
+	%tmp17618 = load i32** getelementptr ([65 x i32*]* @last, i32 0, i32 1), align 4		; <i32*> [#uses=0]
+	br label %cond_true116
+
+cond_true116:		; preds = %cond_true111
+	br i1 false, label %cond_true128, label %cond_true145
+
+cond_true128:		; preds = %cond_true121
+	%tmp17625 = load i32** getelementptr ([65 x i32*]* @last, i32 0, i32 1), align 4		; <i32*> [#uses=0]
+	br i1 false, label %bb98.backedge, label %return.loopexit
+
+bb98.backedge:		; preds = %bb171, %cond_true145, %cond_true128
+	br label %cond_true116
+
+cond_true145:		; preds = %cond_false
+	%tmp17631 = load i32** getelementptr ([65 x i32*]* @last, i32 0, i32 1), align 4		; <i32*> [#uses=0]
+	br i1 false, label %bb98.backedge, label %return.loopexit
+
+return.loopexit:		; preds = %bb171, %cond_true145, %cond_true128
+	br label %return
+
+return:		; preds = %return.loopexit, %cond_next95, %cond_true85
+	ret i32 0
+}

Added: llvm/trunk/test/Transforms/GVN/2007-07-26-PhiErasure.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GVN/2007-07-26-PhiErasure.ll?rev=40540&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/GVN/2007-07-26-PhiErasure.ll (added)
+++ llvm/trunk/test/Transforms/GVN/2007-07-26-PhiErasure.ll Thu Jul 26 13:26:51 2007
@@ -0,0 +1,28 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis | not grep {tmp298316 =}
+
+	%struct..0anon = type { i32 }
+	%struct.FILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, %struct.__sFILEX*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64 }
+	%struct.__sFILEX = type opaque
+	%struct.__sbuf = type { i8*, i32 }
+	%struct.rtx_def = type { i16, i8, i8, [1 x %struct..0anon] }
+ at n_spills = external global i32		; <i32*> [#uses=2]
+
+define i32 @reload(%struct.rtx_def* %first, i32 %global, %struct.FILE* %dumpfile) {
+cond_next2835.1:		; preds = %cond_next2861
+	%tmp2922 = load i32* @n_spills, align 4		; <i32> [#uses=0]
+	br label %bb2928
+
+bb2928:		; preds = %cond_next2835.1, %cond_next2943
+	br i1 false, label %cond_next2943, label %cond_true2935
+
+cond_true2935:		; preds = %bb2928
+	br label %cond_next2943
+
+cond_next2943:		; preds = %cond_true2935, %bb2928
+	br i1 false, label %bb2982.preheader, label %bb2928
+
+bb2982.preheader:		; preds = %cond_next2943
+	%tmp298316 = load i32* @n_spills, align 4		; <i32> [#uses=0]
+	ret i32 0
+
+}





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