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[NFC][InstCombine] Add tests for (~x) a>> y --> ~(x a>> y) fold (PR48995) 

See https://bugs.llvm.org/show_bug.cgi?id=48995
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Roman Lebedev 2021-02-02 16:54:55 +03:00
parent 9b0b435d79
commit e6a061ed9f
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llvm/test/Transforms/InstCombine/hoist-not-from-ashr-operand.ll Normal file
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; Transform
; (~x) a>> y
; into:
; ~(x a>> y)
declare void @use8(i8)
; Most basic positive test
define i8 @t0(i8 %x, i8 %y) {
; CHECK-LABEL: @t0(
; CHECK-NEXT: [[NOT_X:%.*]] = xor i8 [[X:%.*]], -1
; CHECK-NEXT: [[ASHR:%.*]] = ashr i8 [[NOT_X]], [[Y:%.*]]
; CHECK-NEXT: ret i8 [[ASHR]]
;
%not_x = xor i8 %x, -1
%ashr = ashr i8 %not_x, %y
ret i8 %ashr
}
; 'exact'-ness isn't preserved!
define i8 @t1(i8 %x, i8 %y) {
; CHECK-LABEL: @t1(
; CHECK-NEXT: [[NOT_X:%.*]] = xor i8 [[X:%.*]], -1
; CHECK-NEXT: [[ASHR:%.*]] = ashr exact i8 [[NOT_X]], [[Y:%.*]]
; CHECK-NEXT: ret i8 [[ASHR]]
;
%not_x = xor i8 %x, -1
%ashr = ashr exact i8 %not_x, %y
ret i8 %ashr
}
; Basic vector test
define <2 x i8> @t2_vec(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @t2_vec(
; CHECK-NEXT: [[NOT_X:%.*]] = xor <2 x i8> [[X:%.*]], <i8 -1, i8 -1>
; CHECK-NEXT: [[ASHR:%.*]] = ashr <2 x i8> [[NOT_X]], [[Y:%.*]]
; CHECK-NEXT: ret <2 x i8> [[ASHR]]
;
%not_x = xor <2 x i8> %x, <i8 -1, i8 -1>
%ashr = ashr <2 x i8> %not_x, %y
ret <2 x i8> %ashr
}
; Note that we must sanitize undef elts of -1 constant to -1 or 0.
define <2 x i8> @t3_vec_undef(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @t3_vec_undef(
; CHECK-NEXT: [[NOT_X:%.*]] = xor <2 x i8> [[X:%.*]], <i8 -1, i8 undef>
; CHECK-NEXT: [[ASHR:%.*]] = ashr <2 x i8> [[NOT_X]], [[Y:%.*]]
; CHECK-NEXT: ret <2 x i8> [[ASHR]]
;
%not_x = xor <2 x i8> %x, <i8 -1, i8 undef>
%ashr = ashr <2 x i8> %not_x, %y
ret <2 x i8> %ashr
}
; Extra use prevents the fold.
define i8 @n4(i8 %x, i8 %y) {
; CHECK-LABEL: @n4(
; CHECK-NEXT: [[NOT_X:%.*]] = xor i8 [[X:%.*]], -1
; CHECK-NEXT: call void @use8(i8 [[NOT_X]])
; CHECK-NEXT: [[ASHR:%.*]] = ashr i8 [[NOT_X]], [[Y:%.*]]
; CHECK-NEXT: ret i8 [[ASHR]]
;
%not_x = xor i8 %x, -1
call void @use8(i8 %not_x)
%ashr = ashr i8 %not_x, %y
ret i8 %ashr
}