llvm-project/llvm/test/Transforms/InstCombine/bswap-known-bits.ll

; RUN: opt < %s -S -instcombine | FileCheck %s
; Note: This is testing functionality in computeKnownBits.  I'd have rather
; used instsimplify, but the bit test folding is apparently only in instcombine.

declare i16 @llvm.bswap.i16(i16)
declare i32 @llvm.bswap.i32(i32)

define i1 @test1(i16 %arg) {
; CHECK-LABEL: @test1
; CHECK: ret i1 true
  %a = or i16 %arg, 511
  %b = call i16 @llvm.bswap.i16(i16 %a)
  %and = and i16 %b, 256
  %res = icmp eq i16 %and, 256
  ret i1 %res
}

define i1 @test2(i16 %arg) {
; CHECK-LABEL: @test2
; CHECK: ret i1 true
  %a = or i16 %arg, 1
  %b = call i16 @llvm.bswap.i16(i16 %a)
  %and = and i16 %b, 256
  %res = icmp eq i16 %and, 256
  ret i1 %res
}


define i1 @test3(i16 %arg) {
; CHECK-LABEL: @test3
; CHECK: ret i1 true
  %a = or i16 %arg, 256
  %b = call i16 @llvm.bswap.i16(i16 %a)
  %and = and i16 %b, 1
  %res = icmp eq i16 %and, 1
  ret i1 %res
}

define i1 @test4(i32 %arg) {
; CHECK-LABEL: @test4
; CHECK: ret i1 true
  %a = or i32 %arg, 2147483647  ; i32_MAX
  %b = call i32 @llvm.bswap.i32(i32 %a)
  %and = and i32 %b, 127
  %res = icmp eq i32 %and, 127
  ret i1 %res
}