Index: lib/Transforms/Scalar/SCCP.cpp
===================================================================
--- lib/Transforms/Scalar/SCCP.cpp
+++ lib/Transforms/Scalar/SCCP.cpp
@@ -1019,15 +1019,23 @@
 
 // Handle ICmpInst instruction.
 void SCCPSolver::visitCmpInst(CmpInst &I) {
-  LatticeVal V1State = getValueState(I.getOperand(0));
-  LatticeVal V2State = getValueState(I.getOperand(1));
+  ValueLatticeElement V1State = getValueState(I.getOperand(0)).toValueLattice();
+  ValueLatticeElement V2State = getValueState(I.getOperand(1)).toValueLattice();
 
   LatticeVal &IV = ValueState[&I];
   if (IV.isOverdefined()) return;
 
-  if (V1State.isConstant() && V2State.isConstant()) {
-    Constant *C = ConstantExpr::getCompare(
-        I.getPredicate(), V1State.getConstant(), V2State.getConstant());
+  // For parameters, use ParamState which includes constant range info if
+  // available.
+  auto V1Param = ParamState.find(I.getOperand(0));
+  auto V2Param = ParamState.find(I.getOperand(1));
+  if (V1Param != ParamState.end())
+    V1State = V1Param->second;
+  if (V2Param != ParamState.end())
+    V2State = V2Param->second;
+
+  Constant *C = V1State.getCompare(I.getPredicate(), I.getType(), V2State);
+  if (C) {
     if (isa<UndefValue>(C))
       return;
     return markConstant(IV, &I, C);
Index: test/Transforms/SCCP/ip-constant-ranges.ll
===================================================================
--- test/Transforms/SCCP/ip-constant-ranges.ll
+++ test/Transforms/SCCP/ip-constant-ranges.ll
@@ -2,11 +2,7 @@
 
 ; Constant range for %a is [1, 48) and for %b is [301, 1000)
 ; CHECK-LABEL: f1
-; CHECK-NOT: icmp
-; CHECK: %a.1 = select i1 false, i32 1, i32 2
-; CHECK: %b.1 = select i1 true, i32 1, i32 2
-; CHECK: %a.2 = select i1 false, i32 1, i32 2
-; CHECK: %b.2 = select i1 true, i32 1, i32 2
+; CHECK: ret i32 undef
 define internal i32 @f1(i32 %a, i32 %b) {
 entry:
   %cmp.a = icmp sgt i32 %a, 300
@@ -28,10 +24,11 @@
 ; CHECK-LABEL: f2
 ; CHECK: %cmp = icmp sgt i32 %x, 300
 ; CHECK: %res1 = select i1 %cmp, i32 1, i32 2
-; CHECK-NEXT: %res2 = select i1 true, i32 3, i32 4
-; CHECK-NEXT: %res3 = select i1 true, i32 5, i32 6
 ; CHECK-NEXT: %res4 = select i1 %cmp4, i32 3, i32 4
-; CHECK-NEXT: %res5 = select i1 true, i32 5, i32 6
+; CHECK-NEXT: %res6 = add i32 %res1, 3
+; CHECK-NEXT: %res7 = add i32 5, %res4
+; CHECK-NEXT: %res = add i32 %res6, 5
+; CHECK-NEXT: ret i32 %res
 define internal i32 @f2(i32 %x) {
 entry:
   %cmp = icmp sgt i32 %x, 300
@@ -57,8 +54,7 @@
   %call2 = tail call i32 @f1(i32 47, i32 999)
   %call3 = tail call i32 @f2(i32 47)
   %call4 = tail call i32 @f2(i32 301)
-  %res = add nsw i32 %call1, %call2
-  %res.1 = add nsw i32 %res, %call3
+  %res.1 = add nsw i32 12, %call3
   %res.2 = add nsw i32 %res.1, %call4
   ret i32 %res.2
 }