Fix a crash in APInt::lshr when shiftAmt > BitWidth.

Patch by James Benton <jbenton@vmware.com>.

llvm-svn: 158213

llvm/lib/Support/APInt.cpp

@@ -1135,7 +1135,7 @@ APInt APInt::lshr(unsigned shiftAmt) const {
   // If all the bits were shifted out, the result is 0. This avoids issues
   // with shifting by the size of the integer type, which produces undefined
   // results. We define these "undefined results" to always be 0.
-  if (shiftAmt == BitWidth)
+  if (shiftAmt >= BitWidth)
     return APInt(BitWidth, 0);
 
   // If none of the bits are shifted out, the result is *this. This avoids

llvm/test/CodeGen/Generic/2012-06-08-APIntCrash.ll

@@ -0,0 +1,8 @@
+; RUN: llc < %s
+
+define <8 x i32> @test1(<8 x i32>* %ptr)
+{
+	%1 = load <8 x i32>* %ptr, align 32
+	%2 = and <8 x i32> %1, <i32 0, i32 0, i32 0, i32 -1, i32 0, i32 0, i32 0, i32 -1>
+	ret <8 x i32> %2;
+}