Fix InstCombine/2007-10-31-StringCrash.ll by removing an obvious

(in hindsight) infinite recursion.  Simplify the code.

llvm-svn: 43597

2 files changed, 29 insertions, 12 deletions

diff --git a/llvm/lib/VMCore/Constants.cpp b/llvm/lib/VMCore/Constants.cpp
index 262595fc8f3..74f62874501 100644
--- a/llvm/lib/VMCore/Constants.cpp
+++ b/llvm/lib/VMCore/Constants.cpp
@@ -2268,18 +2268,14 @@ std::string Constant::getStringValue(bool Chop, unsigned Offset) {
         }
       }
     }
-  } else if (Constant *C = dyn_cast<Constant>(this)) {
-    if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
-      return GV->getStringValue(Chop, Offset);
-    else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
-      if (CE->getOpcode() == Instruction::GetElementPtr) {
-        // Turn a gep into the specified offset.
-        if (CE->getNumOperands() == 3 &&
-            cast<Constant>(CE->getOperand(1))->isNullValue() &&
-            isa<ConstantInt>(CE->getOperand(2))) {
-          Offset += cast<ConstantInt>(CE->getOperand(2))->getZExtValue();
-          return CE->getOperand(0)->getStringValue(Chop, Offset);
-        }
+  } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
+    if (CE->getOpcode() == Instruction::GetElementPtr) {
+      // Turn a gep into the specified offset.
+      if (CE->getNumOperands() == 3 &&
+          cast<Constant>(CE->getOperand(1))->isNullValue() &&
+          isa<ConstantInt>(CE->getOperand(2))) {
+        Offset += cast<ConstantInt>(CE->getOperand(2))->getZExtValue();
+        return CE->getOperand(0)->getStringValue(Chop, Offset);
       }
     }
   }
diff --git a/llvm/test/Transforms/InstCombine/2007-10-31-StringCrash.ll b/llvm/test/Transforms/InstCombine/2007-10-31-StringCrash.ll
new file mode 100644
index 00000000000..6ba07e8a5a1
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/2007-10-31-StringCrash.ll
@@ -0,0 +1,21 @@
+; RUN: llvm-as < %s | opt -instcombine -disable-output
+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-f80:128:128"
+target triple = "i686-apple-darwin8"
+
+declare void @__darwin_gcc3_preregister_frame_info()
+
+define void @_start(i32 %argc, i8** %argv, i8** %envp) {
+entry:
+	%tmp1 = bitcast void ()* @__darwin_gcc3_preregister_frame_info to i32*		; <i32*> [#uses=1]
+	%tmp2 = load i32* %tmp1, align 4		; <i32> [#uses=1]
+	%tmp3 = icmp ne i32 %tmp2, 0		; <i1> [#uses=1]
+	%tmp34 = zext i1 %tmp3 to i8		; <i8> [#uses=1]
+	%toBool = icmp ne i8 %tmp34, 0		; <i1> [#uses=1]
+	br i1 %toBool, label %cond_true, label %return
+
+cond_true:		; preds = %entry
+	ret void
+
+return:		; preds = %entry
+	ret void
+}