d9962c400f
This flag indicates that every bit is known to be zero in at least one of the inputs. This allows the Or to be treated as an Add since there is no possibility of a carry from any bit. If the flag is present and this property does not hold, the result is poison. This makes it easier to reverse the InstCombine transform that turns Add into Or. This is inspired by a comment here https://github.com/llvm/llvm-project/pull/71955#discussion_r1391614578 Discourse thread https://discourse.llvm.org/t/rfc-add-or-disjoint-flag/75036
37 lines
1.3 KiB
LLVM
37 lines
1.3 KiB
LLVM
; RUN: llvm-as < %s | llvm-dis > %t0
|
|
; RUN: opt -S < %s > %t1
|
|
; RUN: diff %t0 %t1
|
|
; RUN: verify-uselistorder < %s
|
|
; PR6140
|
|
|
|
; Make sure the flags are serialized/deserialized properly for both
|
|
; forward and backward references.
|
|
|
|
define void @foo() nounwind {
|
|
entry:
|
|
br label %first
|
|
|
|
second: ; preds = %first
|
|
%u = add nuw i32 %a, 0 ; <i32> [#uses=0]
|
|
%s = add nsw i32 %a, 0 ; <i32> [#uses=0]
|
|
%us = add nuw nsw i32 %a, 0 ; <i32> [#uses=0]
|
|
%z = add i32 %a, 0 ; <i32> [#uses=0]
|
|
%hh = zext nneg i32 %a to i64
|
|
%ll = zext i32 %s to i64
|
|
%jj = or disjoint i32 %a, 0
|
|
%oo = or i32 %a, 0
|
|
unreachable
|
|
|
|
first: ; preds = %entry
|
|
%a = bitcast i32 0 to i32 ; <i32> [#uses=8]
|
|
%uu = add nuw i32 %a, 0 ; <i32> [#uses=0]
|
|
%ss = add nsw i32 %a, 0 ; <i32> [#uses=0]
|
|
%uuss = add nuw nsw i32 %a, 0 ; <i32> [#uses=0]
|
|
%zz = add i32 %a, 0 ; <i32> [#uses=0]
|
|
%kk = zext nneg i32 %a to i64
|
|
%rr = zext i32 %ss to i64
|
|
%mm = or disjoint i32 %a, 0
|
|
%nn = or i32 %a, 0
|
|
br label %second
|
|
}
|