llvm/test/Transforms/InstSimplify/exact-nsw-nuw.ll
Chris Lattner 81a0dc9115 Teach instsimplify some tricks about exact/nuw/nsw shifts.
improve interfaces to instsimplify to take this info.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125196 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 17:15:04 +00:00

45 lines
779 B
LLVM

; RUN: opt < %s -instsimplify -S | FileCheck %s
; PR8862
; CHECK: @shift1
; CHECK: ret i32 %A
define i32 @shift1(i32 %A, i32 %B) {
%C = lshr exact i32 %A, %B
%D = shl nuw i32 %C, %B
ret i32 %D
}
; CHECK: @shift2
; CHECK: lshr
; CHECK: ret i32 %D
define i32 @shift2(i32 %A, i32 %B) {
%C = lshr i32 %A, %B
%D = shl nuw i32 %C, %B
ret i32 %D
}
; CHECK: @shift3
; CHECK: ret i32 %A
define i32 @shift3(i32 %A, i32 %B) {
%C = ashr exact i32 %A, %B
%D = shl nuw i32 %C, %B
ret i32 %D
}
; CHECK: @shift4
; CHECK: ret i32 %A
define i32 @shift4(i32 %A, i32 %B) {
%C = shl nuw i32 %A, %B
%D = lshr i32 %C, %B
ret i32 %D
}
; CHECK: @shift5
; CHECK: ret i32 %A
define i32 @shift5(i32 %A, i32 %B) {
%C = shl nsw i32 %A, %B
%D = ashr i32 %C, %B
ret i32 %D
}