+; RUN: opt < %s -S -instcombine | FileCheck %s
+
+declare i32 @llvm.ctpop.i32(i32)
+declare i8 @llvm.ctpop.i8(i8)
+declare void @llvm.assume(i1)
+
+define i1 @test1(i32 %arg) {
+; CHECK: @test1
+; CHECK: ret i1 false
+ %and = and i32 %arg, 15
+ %cnt = call i32 @llvm.ctpop.i32(i32 %and)
+ %res = icmp eq i32 %cnt, 9
+ ret i1 %res
+}
+
+define i1 @test2(i32 %arg) {
+; CHECK: @test2
+; CHECK: ret i1 false
+ %and = and i32 %arg, 1
+ %cnt = call i32 @llvm.ctpop.i32(i32 %and)
+ %res = icmp eq i32 %cnt, 2
+ ret i1 %res
+}
+
+define i1 @test3(i32 %arg) {
+; CHECK: @test3
+; CHECK: ret i1 false
+ ;; Use an assume to make all the bits known without triggering constant
+ ;; folding. This is trying to hit a corner case where we have to avoid
+ ;; taking the log of 0.
+ %assume = icmp eq i32 %arg, 0
+ call void @llvm.assume(i1 %assume)
+ %cnt = call i32 @llvm.ctpop.i32(i32 %arg)
+ %res = icmp eq i32 %cnt, 2
+ ret i1 %res
+}
+
+; Negative test for when we know nothing
+define i1 @test4(i8 %arg) {
+; CHECK: @test4
+; CHECK: ret i1 %res
+ %cnt = call i8 @llvm.ctpop.i8(i8 %arg)
+ %res = icmp eq i8 %cnt, 2
+ ret i1 %res
+}