[llvm-commits] [llvm] r72364 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolutionExpander.h lib/Analysis/ScalarEvolutionExpander.cpp lib/Transforms/Scalar/IndVarSimplify.cpp test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll

Torok Edwin edwintorok at gmail.com
Sun May 24 07:23:30 PDT 2009


Author: edwin
Date: Sun May 24 09:23:16 2009
New Revision: 72364

URL: http://llvm.org/viewvc/llvm-project?rev=72364&view=rev
Log:
The rewriter may hold references to instructions that are deleted because they are trivially dead.
Fix by clearing the rewriter cache before deleting the trivially dead
instructions.
Also make InsertedExpressions use an AssertingVH to catch these
bugs easier.

Added:
    llvm/trunk/test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll
Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
    llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
    llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h?rev=72364&r1=72363&r2=72364&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h Sun May 24 09:23:16 2009
@@ -28,7 +28,7 @@
   /// memory.
   struct SCEVExpander : public SCEVVisitor<SCEVExpander, Value*> {
     ScalarEvolution &SE;
-    std::map<SCEVHandle, Value*> InsertedExpressions;
+    std::map<SCEVHandle, AssertingVH<Value> > InsertedExpressions;
     std::set<Value*> InsertedValues;
 
     BasicBlock::iterator InsertPt;

Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=72364&r1=72363&r2=72364&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Sun May 24 09:23:16 2009
@@ -526,7 +526,7 @@
 
 Value *SCEVExpander::expand(const SCEV *S) {
   // Check to see if we already expanded this.
-  std::map<SCEVHandle, Value*>::iterator I = InsertedExpressions.find(S);
+  std::map<SCEVHandle, AssertingVH<Value> >::iterator I = InsertedExpressions.find(S);
   if (I != InsertedExpressions.end())
     return I->second;
   

Modified: llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp?rev=72364&r1=72363&r2=72364&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/IndVarSimplify.cpp Sun May 24 09:23:16 2009
@@ -298,6 +298,7 @@
         // in the loop, so we don't need an LCSSA phi node anymore.
         if (NumPreds == 1) {
           PN->replaceAllUsesWith(ExitVal);
+          Rewriter.clear();
           RecursivelyDeleteTriviallyDeadInstructions(PN);
           break;
         }
@@ -418,6 +419,7 @@
   // Reorder instructions to avoid use-before-def conditions.
   FixUsesBeforeDefs(L, Rewriter);
 
+  Rewriter.clear();
   // For completeness, inform IVUsers of the IV use in the newly-created
   // loop exit test instruction.
   if (NewICmp)

Added: llvm/trunk/test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll?rev=72364&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/2009-05-24-useafterfree.ll Sun May 24 09:23:16 2009
@@ -0,0 +1,41 @@
+; RUN: llvm-as < %s | opt -indvars
+; PR4258
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
+target triple = "i386-linux-gnu"
+
+define void @0(i32*, i32*, i32, i32) nounwind {
+	br i1 false, label %bb.nph1.preheader, label %.outer._crit_edge
+
+bb.nph1.preheader:		; preds = %4
+	%smax = select i1 false, i32 -1, i32 0		; <i32> [#uses=1]
+	%tmp12 = sub i32 0, %smax		; <i32> [#uses=1]
+	br label %bb.nph1
+
+bb.nph1:		; preds = %.outer, %bb.nph1.preheader
+	br i1 false, label %bb.nph3.preheader, label %.outer
+
+bb.nph3.preheader:		; preds = %bb.nph1
+	br label %bb.nph3
+
+bb.nph3:		; preds = %bb.nph3, %bb.nph3.preheader
+	%indvar7 = phi i32 [ %indvar.next8, %bb.nph3 ], [ 0, %bb.nph3.preheader ]		; <i32> [#uses=3]
+	%tmp9 = mul i32 %indvar7, -1		; <i32> [#uses=1]
+	%tmp13 = add i32 %tmp9, %tmp12		; <i32> [#uses=1]
+	%tmp14 = add i32 %tmp13, -2		; <i32> [#uses=1]
+	%5 = icmp sgt i32 %tmp14, 0		; <i1> [#uses=1]
+	%indvar.next8 = add i32 %indvar7, 1		; <i32> [#uses=1]
+	br i1 %5, label %bb.nph3, label %.outer.loopexit
+
+.outer.loopexit:		; preds = %bb.nph3
+	%indvar7.lcssa = phi i32 [ %indvar7, %bb.nph3 ]		; <i32> [#uses=0]
+	br label %.outer
+
+.outer:		; preds = %.outer.loopexit, %bb.nph1
+	br i1 false, label %bb.nph1, label %.outer._crit_edge.loopexit
+
+.outer._crit_edge.loopexit:		; preds = %.outer
+	br label %.outer._crit_edge
+
+.outer._crit_edge:		; preds = %.outer._crit_edge.loopexit, %4
+	ret void
+}





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