Index: lib/Transforms/Scalar/SCCP.cpp
===================================================================
--- lib/Transforms/Scalar/SCCP.cpp
+++ lib/Transforms/Scalar/SCCP.cpp
@@ -1902,13 +1902,15 @@
 
   // Solve for constants.
   bool ResolvedUndefs = true;
+  Solver.Solve();
   while (ResolvedUndefs) {
-    Solver.Solve();
-
     LLVM_DEBUG(dbgs() << "RESOLVING UNDEFS\n");
     ResolvedUndefs = false;
     for (Function &F : M)
-      ResolvedUndefs |= Solver.ResolvedUndefsIn(F);
+      if (Solver.ResolvedUndefsIn(F)) {
+        Solver.Solve();
+        ResolvedUndefs = true;
+      }
   }
 
   bool MadeChanges = false;
Index: test/Transforms/IPConstantProp/solve-after-each-resolving-undefs-for-function.ll
===================================================================
--- /dev/null
+++ test/Transforms/IPConstantProp/solve-after-each-resolving-undefs-for-function.ll
@@ -0,0 +1,39 @@
+; RUN: opt < %s -S -ipsccp | FileCheck %s
+
+; We re-run the solver each time we resolved an undef in a function. This allows
+; us to find the constant return value of @testf before resolving undefs in
+; @test1.
+define internal i1 @testf() {
+; CHECK-LABEL: define internal i1 @testf(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[IF_END3:%.*]]
+; CHECK:       if.end3:
+; CHECK-NEXT:    ret i1 undef
+;
+entry:
+  br i1 undef, label %if.then1, label %if.end3
+
+if.then1:                                         ; preds = %if.end
+  br label %if.end3
+
+if.end3:                                          ; preds = %if.then1, %entry
+  ret i1 true
+}
+
+define void @test1() {
+; CHECK-LABEL: @test1(
+; CHECK-LABEL: if.then:
+; CHECK:         call i1 @testf()
+; CHECK-NEXT:    br i1 true, label %if.end, label %if.then
+;
+entry:
+  br label %if.then
+if.then:                                          ; preds = %entry, %if.then
+  %foo = phi i32 [ 0, %entry], [ %next, %if.then]
+  %next = add i32 %foo, 1
+  %call = call i1 @testf()
+  br i1 %call, label %if.end, label %if.then
+
+if.end:                                           ; preds = %if.then, %entry
+  ret void
+}
Index: test/Transforms/SCCP/ipsccp-basic.ll
===================================================================
--- test/Transforms/SCCP/ipsccp-basic.ll
+++ test/Transforms/SCCP/ipsccp-basic.ll
@@ -253,7 +253,7 @@
   ret void
 ; CHECK-LABEL: define void @test11b
 ; CHECK: %[[call1:.*]] = call i64 @test11a()
-; CHECK: %[[call2:.*]] = call i64 @llvm.ctpop.i64(i64 0)
+; CHECK-NOT: call i64 @llvm.ctpop.i64
 }
 
 declare i64 @llvm.ctpop.i64(i64)