llvm/test/Transforms/InstCombine/trunc-mask-ext.ll
Dan Gohman fd3daa74c2 Generalize the zext(trunc(t) & C) instcombine to work even with
C is not a low-bits mask, and add a similar instcombine for
zext((trunc(t) & C) ^ C).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73705 91177308-0d34-0410-b5e6-96231b3b80d8
2009-06-18 16:30:21 +00:00

39 lines
799 B
LLVM

; RUN: llvm-as < %s | opt -instcombine | llvm-dis > %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
}