Index: llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -861,7 +861,7 @@
         if (LoadInst *Ld = dyn_cast<LoadInst>(I->getOperand(0)))
           if (const ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1)))
             if (!Ld->hasOneUse() && Ld->getParent() == I->getParent() &&
-                C->getZExtValue() == 0)
+                C->isZero())
               return 0;
 
       unsigned Cost = 1;
@@ -1020,7 +1020,7 @@
     // Comparison between memory and immediate.
     if (UserI->getOpcode() == Instruction::ICmp)
       if (ConstantInt *CI = dyn_cast<ConstantInt>(UserI->getOperand(1)))
-        if (isUInt<16>(CI->getZExtValue()))
+        if (CI->getValue().isIntN(16))
           return true;
     return (LoadOrTruncBits == 32 || LoadOrTruncBits == 64);
     break;
Index: llvm/test/Analysis/CostModel/SystemZ/huge-immediates.ll
===================================================================
--- /dev/null
+++ llvm/test/Analysis/CostModel/SystemZ/huge-immediates.ll
@@ -0,0 +1,20 @@
+; RUN: opt < %s -cost-model -analyze -mtriple=systemz-unknown -mcpu=z13
+;
+; Test that cost functions can handle immediates of more than 64 bits without crashing.
+
+; Cost of a load which is checked for folding into a compare w/ memory.
+define i32 @fun0(i72* %Src) {
+  %L = load i72, i72* %Src
+  %B = icmp ult i72 %L, 166153499473114484112
+  %Res = zext i1 %B to i32
+  ret i32 %Res
+}
+
+; Cost of a compare which is checked for elimination by Load and Test.
+define i32 @fun1(i72* %Src, i72* %Dst) {
+  %L = load i72, i72* %Src
+  store i72 %L, i72* %Dst
+  %B = icmp ult i72 %L, 166153499473114484112
+  %Res = zext i1 %B to i32
+  ret i32 %Res
+}