Fix a bug that was causing GVN to crash on 252.eon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40494 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index 3b8adef4aa79ffb1b8fdf11518f594cde4a7d2b6..a08ee68ca62ff6c993897bb7999426925067ef49 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -714,8 +714,15 @@ Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
   unsigned numPreds = std::distance(pred_begin(BB), pred_end(BB));
   
   if (numPreds == 1) {
-    Phis[BB] = Phis[*pred_begin(BB)];
-    return Phis[BB];
+    DenseMap<BasicBlock*, Value*>::iterator DI = Phis.find(BB);
+    if (DI != Phis.end()) {
+      Phis.insert(std::make_pair(BB, DI->second));
+      return DI->second;
+    } else {
+      Value* domV = performPHIConstruction(*pred_begin(BB), orig, Phis);
+      Phis.insert(std::make_pair(BB, domV));
+      return domV;
+    }
   } else {
     PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle", BB->begin());
     PN->reserveOperandSpace(numPreds);

diff --git a/test/Transforms/GVN/2007-07-25-SinglePredecessor.ll b/test/Transforms/GVN/2007-07-25-SinglePredecessor.ll
new file mode 100644 (file)
index 0000000..10482d8
--- /dev/null
+++ b/test/Transforms/GVN/2007-07-25-SinglePredecessor.ll
@@ -0,0 +1,29 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis
+
+       %struct.ggBRDF = type { i32 (...)** }
+       %struct.ggBox3 = type { %struct.ggPoint3, %struct.ggPoint3 }
+       %struct.ggMaterialRecord = type { %struct.ggPoint2, %struct.ggBox3, %struct.ggBox3, %struct.ggSpectrum, %struct.ggSpectrum, %struct.ggSpectrum, %struct.ggBRDF*, i32, i32, i32, i32 }
+       %struct.ggONB3 = type { %struct.ggPoint3, %struct.ggPoint3, %struct.ggPoint3 }
+       %struct.ggPoint2 = type { [2 x double] }
+       %struct.ggPoint3 = type { [3 x double] }
+       %struct.ggSpectrum = type { [8 x float] }
+       %struct.mrViewingHitRecord = type { double, %struct.ggPoint3, %struct.ggONB3, %struct.ggPoint2, double, %struct.ggSpectrum, %struct.ggSpectrum, i32, i32, i32, i32 }
+       %struct.mrXEllipticalCylinder = type { %struct.ggBRDF, float, float, float, float, float, float }
+
+define i32 @_ZNK21mrZEllipticalCylinder10viewingHitERK6ggRay3dddR18mrViewingHitRecordR16ggMaterialRecord(%struct.mrXEllipticalCylinder* %this, %struct.ggBox3* %ray, double %unnamed_arg, double %tmin, double %tmax, %struct.mrViewingHitRecord* %VHR, %struct.ggMaterialRecord* %unnamed_arg2) {
+entry:
+       %tmp80.i = getelementptr %struct.mrViewingHitRecord* %VHR, i32 0, i32 1, i32 0, i32 0           ; <double*> [#uses=1]
+       store double 0.000000e+00, double* %tmp80.i
+       br i1 false, label %return, label %cond_next.i
+
+cond_next.i:           ; preds = %entry
+       br i1 false, label %return, label %cond_true
+
+cond_true:             ; preds = %cond_next.i
+       %tmp3.i8 = getelementptr %struct.mrViewingHitRecord* %VHR, i32 0, i32 1, i32 0, i32 0           ; <double*> [#uses=1]
+       %tmp46 = load double* %tmp3.i8          ; <double> [#uses=0]
+       ret i32 1
+
+return:                ; preds = %cond_next.i, %entry
+       ret i32 0
+}