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Differential D124369 Diff 424850 llvm/test/Transforms/InstCombine/shift-add.ll

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llvm/test/Transforms/InstCombine/shift-add.ll

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; CHECK-NEXT: [[R:%.*]] = shl i32 6, [[A]] ; CHECK-NEXT: [[R:%.*]] = shl i32 6, [[A]]
; CHECK-NEXT: ret i32 [[R]] ; CHECK-NEXT: ret i32 [[R]]
; ;
%a = add nsw i32 %x, 5 %a = add nsw i32 %x, 5
%r = shl i32 6, %a %r = shl i32 6, %a
ret i32 %r ret i32 %r
} }
define i32 @lshr_add_negative(i32 %x) {
; CHECK-LABEL: @lshr_add_positive(
; CHECK-NEXT: [[R:%.*]] = lshr i32 4, [[X:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%a = add i32 %x, -1
%r = lshr i32 2, %a
ret i32 %r
}
define i32 @ashr_exact_add_negative(i32 %x) {
; CHECK-LABEL: @ashr_exact_add_negative(
; CHECK-NEXT: [[R:%.*]] = ashr i32 -4, [[X:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%a = add i32 %x, -1
%r = ashr exact i32 -2, %a
ret i32 %r
}
; PR54890 ; PR54890
define i32 @shl_nsw_add_negative(i32 %x) { define i32 @shl_nsw_add_negative(i32 %x) {
; CHECK-LABEL: @shl_nsw_add_negative( ; CHECK-LABEL: @shl_nsw_add_negative(
; CHECK-NEXT: [[R:%.*]] = shl i32 1, [[X:%.*]] ; CHECK-NEXT: [[R:%.*]] = shl i32 1, [[X:%.*]]
; CHECK-NEXT: ret i32 [[R]] ; CHECK-NEXT: ret i32 [[R]]
; ;
%a = add i32 %x, -1 %a = add i32 %x, -1
%r = shl nsw i32 2, %a %r = shl nsw i32 2, %a
ret i32 %r ret i32 %r
spatelUnsubmitted
Done
ReplyInline Actions

If the constant is not negative, the ashr will get converted to lshr before we hit the new transform, so this test is not providing the coverage that we want. How about something like this:

%a = add i8 %x, -4
%r = ashr exact i8 -112, %a ; 0b1001_0000
spatel: If the constant is not negative, the ashr will get converted to lshr before we hit the new…
} }
; vectors and extra uses are allowed ; vectors and extra uses are allowed
; nuw propagates to the new shift ; nuw propagates to the new shift
define <2 x i8> @shl_nuw_add_negative_splat_uses(<2 x i8> %x, <2 x i8>* %p) { define <2 x i8> @shl_nuw_add_negative_splat_uses(<2 x i8> %x, <2 x i8>* %p) {
; CHECK-LABEL: @shl_nuw_add_negative_splat_uses( ; CHECK-LABEL: @shl_nuw_add_negative_splat_uses(
; CHECK-NEXT: [[A:%.*]] = add <2 x i8> [[X:%.*]], <i8 -2, i8 -2> ; CHECK-NEXT: [[A:%.*]] = add <2 x i8> [[X:%.*]], <i8 -2, i8 -2>
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