167 lines
4.8 KiB
LLVM
167 lines
4.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt < %s -instcombine -S | FileCheck %s
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; PR51305: prefer `-(x & 1)` over `(x << (bitwidth(x)-1)) a>> (bitwidth(x)-1)`
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; as the pattern to splat the lowest bit.
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declare void @use8(i8)
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; Basic positive scalar tests
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define i8 @t0(i8 %x) {
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; CHECK-LABEL: @t0(
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; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X:%.*]], 1
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; CHECK-NEXT: [[R:%.*]] = sub nsw i8 0, [[TMP1]]
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = shl i8 %x, 7
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%r = ashr i8 %i0, 7
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ret i8 %r
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}
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define i16 @t1_otherbitwidth(i16 %x) {
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; CHECK-LABEL: @t1_otherbitwidth(
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; CHECK-NEXT: [[TMP1:%.*]] = and i16 [[X:%.*]], 1
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; CHECK-NEXT: [[R:%.*]] = sub nsw i16 0, [[TMP1]]
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; CHECK-NEXT: ret i16 [[R]]
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;
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%i0 = shl i16 %x, 15
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%r = ashr i16 %i0, 15
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ret i16 %r
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}
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; Basic positive vector tests
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define <2 x i8> @t2_vec(<2 x i8> %x) {
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; CHECK-LABEL: @t2_vec(
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; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[X:%.*]], <i8 1, i8 1>
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; CHECK-NEXT: [[R:%.*]] = sub nsw <2 x i8> zeroinitializer, [[TMP1]]
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; CHECK-NEXT: ret <2 x i8> [[R]]
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;
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%i0 = shl <2 x i8> %x, <i8 7, i8 7>
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%r = ashr <2 x i8> %i0, <i8 7, i8 7>
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ret <2 x i8> %r
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}
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define <3 x i8> @t3_vec_undef0(<3 x i8> %x) {
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; CHECK-LABEL: @t3_vec_undef0(
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; CHECK-NEXT: [[TMP1:%.*]] = and <3 x i8> [[X:%.*]], <i8 1, i8 undef, i8 1>
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; CHECK-NEXT: [[R:%.*]] = sub <3 x i8> zeroinitializer, [[TMP1]]
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; CHECK-NEXT: ret <3 x i8> [[R]]
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;
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%i0 = shl <3 x i8> %x, <i8 7, i8 undef, i8 7>
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%r = ashr <3 x i8> %i0, <i8 7, i8 7, i8 7>
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ret <3 x i8> %r
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}
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define <3 x i8> @t4_vec_undef1(<3 x i8> %x) {
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; CHECK-LABEL: @t4_vec_undef1(
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; CHECK-NEXT: [[TMP1:%.*]] = and <3 x i8> [[X:%.*]], <i8 1, i8 undef, i8 1>
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; CHECK-NEXT: [[R:%.*]] = sub <3 x i8> zeroinitializer, [[TMP1]]
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; CHECK-NEXT: ret <3 x i8> [[R]]
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;
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%i0 = shl <3 x i8> %x, <i8 7, i8 7, i8 7>
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%r = ashr <3 x i8> %i0, <i8 7, i8 undef, i8 7>
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ret <3 x i8> %r
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}
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define <3 x i8> @t5_vec_undef2(<3 x i8> %x) {
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; CHECK-LABEL: @t5_vec_undef2(
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; CHECK-NEXT: [[TMP1:%.*]] = and <3 x i8> [[X:%.*]], <i8 1, i8 undef, i8 1>
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; CHECK-NEXT: [[R:%.*]] = sub <3 x i8> zeroinitializer, [[TMP1]]
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; CHECK-NEXT: ret <3 x i8> [[R]]
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;
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%i0 = shl <3 x i8> %x, <i8 7, i8 undef, i8 7>
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%r = ashr <3 x i8> %i0, <i8 7, i8 undef, i8 7>
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ret <3 x i8> %r
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}
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; In general, the `shl` needs to go away.
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define i8 @n6_extrause(i8 %x) {
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; CHECK-LABEL: @n6_extrause(
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; CHECK-NEXT: [[I0:%.*]] = shl i8 [[X:%.*]], 7
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; CHECK-NEXT: call void @use8(i8 [[I0]])
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; CHECK-NEXT: [[R:%.*]] = ashr exact i8 [[I0]], 7
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = shl i8 %x, 7
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call void @use8(i8 %i0)
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%r = ashr i8 %i0, 7
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ret i8 %r
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}
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; But, if the input to the shift is already masked, then we're fine.
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define i8 @t7_already_masked(i8 %x) {
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; CHECK-LABEL: @t7_already_masked(
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; CHECK-NEXT: [[I0:%.*]] = and i8 [[X:%.*]], 1
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; CHECK-NEXT: call void @use8(i8 [[I0]])
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; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X]], 1
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; CHECK-NEXT: [[R:%.*]] = sub nsw i8 0, [[TMP1]]
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = and i8 %x, 1
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call void @use8(i8 %i0)
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%i1 = shl i8 %i0, 7
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%r = ashr i8 %i1, 7
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ret i8 %r
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}
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; FIXME: we should fold this
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define i8 @t8_already_masked_extrause(i8 %x) {
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; CHECK-LABEL: @t8_already_masked_extrause(
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; CHECK-NEXT: [[I0:%.*]] = and i8 [[X:%.*]], 1
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; CHECK-NEXT: call void @use8(i8 [[I0]])
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; CHECK-NEXT: [[I1:%.*]] = shl i8 [[X]], 7
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; CHECK-NEXT: call void @use8(i8 [[I1]])
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; CHECK-NEXT: [[R:%.*]] = ashr exact i8 [[I1]], 7
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = and i8 %x, 1
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call void @use8(i8 %i0)
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%i1 = shl i8 %i0, 7
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call void @use8(i8 %i1)
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%r = ashr i8 %i1, 7
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ret i8 %r
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}
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define i8 @n9_wrongly_masked_extrause(i8 %x) {
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; CHECK-LABEL: @n9_wrongly_masked_extrause(
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; CHECK-NEXT: [[I0:%.*]] = and i8 [[X:%.*]], 3
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; CHECK-NEXT: call void @use8(i8 [[I0]])
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; CHECK-NEXT: [[I1:%.*]] = shl i8 [[X]], 7
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; CHECK-NEXT: call void @use8(i8 [[I1]])
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; CHECK-NEXT: [[R:%.*]] = ashr exact i8 [[I1]], 7
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = and i8 %x, 3
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call void @use8(i8 %i0)
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%i1 = shl i8 %i0, 7
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call void @use8(i8 %i1)
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%r = ashr i8 %i1, 7
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ret i8 %r
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}
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; Wrong shift amounts
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define i8 @n10(i8 %x) {
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; CHECK-LABEL: @n10(
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; CHECK-NEXT: [[I0:%.*]] = shl i8 [[X:%.*]], 6
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; CHECK-NEXT: [[R:%.*]] = ashr i8 [[I0]], 7
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = shl i8 %x, 6 ; not 7
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%r = ashr i8 %i0, 7
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ret i8 %r
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}
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define i8 @n11(i8 %x) {
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; CHECK-LABEL: @n11(
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; CHECK-NEXT: [[I0:%.*]] = shl i8 [[X:%.*]], 7
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; CHECK-NEXT: [[R:%.*]] = ashr exact i8 [[I0]], 6
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = shl i8 %x, 7
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%r = ashr i8 %i0, 6 ; not 7
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ret i8 %r
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}
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define i8 @n12(i8 %x) {
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; CHECK-LABEL: @n12(
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; CHECK-NEXT: [[I0:%.*]] = shl i8 [[X:%.*]], 6
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; CHECK-NEXT: [[R:%.*]] = ashr exact i8 [[I0]], 6
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; CHECK-NEXT: ret i8 [[R]]
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;
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%i0 = shl i8 %x, 6 ; not 7
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%r = ashr i8 %i0, 6 ; not 7
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ret i8 %r
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}
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