llvm-mirror/test/Transforms/InstCombine/trunc-mask-ext.ll

; RUN: opt < %s -instcombine -S > %t
; RUN: not grep zext %t
; RUN: not grep sext %t

; Instcombine should be able to eliminate all of these ext casts.

declare void @use(i32)

define i64 @foo(i64 %a) {
  %b = trunc i64 %a to i32
  %c = and i32 %b, 15
  %d = zext i32 %c to i64
  call void @use(i32 %b)
  ret i64 %d
}
define i64 @bar(i64 %a) {
  %b = trunc i64 %a to i32
  %c = shl i32 %b, 4
  %q = ashr i32 %c, 4
  %d = sext i32 %q to i64
  call void @use(i32 %b)
  ret i64 %d
}
define i64 @goo(i64 %a) {
  %b = trunc i64 %a to i32
  %c = and i32 %b, 8
  %d = zext i32 %c to i64
  call void @use(i32 %b)
  ret i64 %d
}
define i64 @hoo(i64 %a) {
  %b = trunc i64 %a to i32
  %c = and i32 %b, 8
  %x = xor i32 %c, 8
  %d = zext i32 %x to i64
  call void @use(i32 %b)
  ret i64 %d
}