maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[InstCombine] Add tests for D130075 

Differential Revision: https://reviews.llvm.org/D132381
This commit is contained in:
Jay Foad 2022-08-22 16:35:46 +01:00
parent d848186a3b
commit 8b24e64014
1 changed files with 28 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
llvm/test/Transforms/InstCombine/add2.ll
View File

@ -472,3 +472,31 @@ define i32 @add_of_selects(i1 %A, i32 %B) {
%add = add i32 %sel0, %sel1
ret i32 %add
}
; The ADD can't cause overflow out of the low 4 bits so the OR can be removed.
define i32 @add_undemanded_low_bits(i32 %x) {
; CHECK-LABEL: @add_undemanded_low_bits(
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 15
; CHECK-NEXT: [[ADD:%.*]] = add i32 [[OR]], 1616
; CHECK-NEXT: [[SHR:%.*]] = lshr i32 [[ADD]], 4
; CHECK-NEXT: ret i32 [[SHR]]
;
%or = or i32 %x, 15
%add = add i32 %or, 1616
%shr = lshr i32 %add, 4
ret i32 %shr
}
define i32 @sub_undemanded_low_bits(i32 %x) {
; CHECK-LABEL: @sub_undemanded_low_bits(
; CHECK-NEXT: [[OR:%.*]] = or i32 [[X:%.*]], 15
; CHECK-NEXT: [[SUB:%.*]] = add i32 [[OR]], -1616
; CHECK-NEXT: [[SHR:%.*]] = lshr i32 [[SUB]], 4
; CHECK-NEXT: ret i32 [[SHR]]
;
%or = or i32 %x, 15
%sub = sub i32 %or, 1616
%shr = lshr i32 %sub, 4
ret i32 %shr
}