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[InstCombine] Infer shift flags with unknown shamt #72535

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Merged
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Nov 18, 2023
+204 −217
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[InstCombine] Infer shift flags with unknown shamt #72535

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29 changes: 8 additions & 21 deletions llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -964,30 +964,26 @@ static bool setShiftFlags(BinaryOperator &I, const SimplifyQuery &Q) {
// Compute what we know about shift count.
KnownBits KnownCnt =
computeKnownBits(I.getOperand(1), Q.DL, /*Depth*/ 0, Q.AC, Q.CxtI, Q.DT);
// If we know nothing about shift count or its a poison shift, we won't be
// able to prove anything so return before computing shift amount.
if (KnownCnt.isUnknown())
return false;
unsigned BitWidth = KnownCnt.getBitWidth();
APInt MaxCnt = KnownCnt.getMaxValue();
if (MaxCnt.uge(BitWidth))
return false;
// Since shift produces a poison value if RHS is equal to or larger than the
// bit width, we can safely assume that RHS is less than the bit width.
uint64_t MaxCnt = KnownCnt.getMaxValue().getLimitedValue(BitWidth - 1);

KnownBits KnownAmt =
computeKnownBits(I.getOperand(0), Q.DL, /*Depth*/ 0, Q.AC, Q.CxtI, Q.DT);
bool Changed = false;

if (I.getOpcode() == Instruction::Shl) {
// If we have as many leading zeros than maximum shift cnt we have nuw.
if (!I.hasNoUnsignedWrap() && MaxCnt.ule(KnownAmt.countMinLeadingZeros())) {
if (!I.hasNoUnsignedWrap() && MaxCnt <= KnownAmt.countMinLeadingZeros()) {
I.setHasNoUnsignedWrap();
Changed = true;
}
// If we have more sign bits than maximum shift cnt we have nsw.
if (!I.hasNoSignedWrap()) {
if (MaxCnt.ult(KnownAmt.countMinSignBits()) ||
MaxCnt.ult(ComputeNumSignBits(I.getOperand(0), Q.DL, /*Depth*/ 0,
Q.AC, Q.CxtI, Q.DT))) {
if (MaxCnt < KnownAmt.countMinSignBits() ||
MaxCnt < ComputeNumSignBits(I.getOperand(0), Q.DL, /*Depth*/ 0, Q.AC,
Q.CxtI, Q.DT)) {
I.setHasNoSignedWrap();
Changed = true;
}
Expand All @@ -997,7 +993,7 @@ static bool setShiftFlags(BinaryOperator &I, const SimplifyQuery &Q) {

// If we have at least as many trailing zeros as maximum count then we have
// exact.
Changed = MaxCnt.ule(KnownAmt.countMinTrailingZeros());
Changed = MaxCnt <= KnownAmt.countMinTrailingZeros();
I.setIsExact(Changed);

return Changed;
Expand Down Expand Up @@ -1225,15 +1221,6 @@ Instruction *InstCombinerImpl::visitShl(BinaryOperator &I) {
Value *NegX = Builder.CreateNeg(X, "neg");
return BinaryOperator::CreateAnd(NegX, X);
}

// The only way to shift out the 1 is with an over-shift, so that would
// be poison with or without "nuw". Undef is excluded because (undef << X)
// is not undef (it is zero).
Constant *ConstantOne = cast<Constant>(Op0);
if (!I.hasNoUnsignedWrap() && !ConstantOne->containsUndefElement()) {
I.setHasNoUnsignedWrap();
return &I;
}
}

return nullptr;
Expand Down
4 changes: 2 additions & 2 deletions llvm/test/Transforms/InstCombine/binop-of-displaced-shifts.ll
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Expand Up @@ -150,9 +150,9 @@ define i8 @lshr_add_fail(i8 %x) {
define i8 @ashr_add_fail(i8 %x) {
; CHECK-LABEL: define i8 @ashr_add_fail
; CHECK-SAME: (i8 [[X:%.*]]) {
; CHECK-NEXT: [[SHIFT:%.*]] = ashr i8 -128, [[X]]
; CHECK-NEXT: [[SHIFT:%.*]] = ashr exact i8 -128, [[X]]
; CHECK-NEXT: [[ADD:%.*]] = add i8 [[X]], 1
; CHECK-NEXT: [[SHIFT2:%.*]] = ashr i8 -128, [[ADD]]
; CHECK-NEXT: [[SHIFT2:%.*]] = ashr exact i8 -128, [[ADD]]
; CHECK-NEXT: [[BINOP:%.*]] = add i8 [[SHIFT]], [[SHIFT2]]
; CHECK-NEXT: ret i8 [[BINOP]]
;
Expand Down
10 changes: 5 additions & 5 deletions llvm/test/Transforms/InstCombine/canonicalize-ashr-shl-to-masking.ll
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Expand Up @@ -15,7 +15,7 @@

define i8 @positive_samevar(i8 %x, i8 %y) {
; CHECK-LABEL: @positive_samevar(
; CHECK-NEXT: [[TMP1:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[RET:%.*]] = and i8 [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret i8 [[RET]]
;
Expand Down Expand Up @@ -62,7 +62,7 @@ define i8 @positive_biggershl(i8 %x) {

define i8 @positive_samevar_shlnuw(i8 %x, i8 %y) {
; CHECK-LABEL: @positive_samevar_shlnuw(
; CHECK-NEXT: [[TMP1:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[RET:%.*]] = and i8 [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret i8 [[RET]]
;
Expand Down Expand Up @@ -109,7 +109,7 @@ define i8 @positive_biggershl_shlnuw(i8 %x) {

define i8 @positive_samevar_shlnsw(i8 %x, i8 %y) {
; CHECK-LABEL: @positive_samevar_shlnsw(
; CHECK-NEXT: [[TMP1:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[RET:%.*]] = and i8 [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret i8 [[RET]]
;
Expand Down Expand Up @@ -156,7 +156,7 @@ define i8 @positive_biggershl_shlnsw(i8 %x) {

define i8 @positive_samevar_shlnuwnsw(i8 %x, i8 %y) {
; CHECK-LABEL: @positive_samevar_shlnuwnsw(
; CHECK-NEXT: [[TMP1:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[RET:%.*]] = and i8 [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret i8 [[RET]]
;
Expand Down Expand Up @@ -371,7 +371,7 @@ define i8 @positive_biggershl_shlnuwnsw_ashrexact(i8 %x) {

define <2 x i8> @positive_samevar_vec(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @positive_samevar_vec(
; CHECK-NEXT: [[TMP1:%.*]] = shl <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = shl nsw <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: [[RET:%.*]] = and <2 x i8> [[TMP1]], [[X:%.*]]
; CHECK-NEXT: ret <2 x i8> [[RET]]
;
Expand Down
16 changes: 8 additions & 8 deletions llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v2-and-icmp-eq-to-icmp-ule.ll
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Expand Up @@ -142,7 +142,7 @@ declare void @use8(i8)

define i1 @oneuse0(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[X_HIGHBITS:%.*]] = lshr i8 [[X:%.*]], [[Y]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[X_HIGHBITS]], 0
Expand All @@ -158,7 +158,7 @@ define i1 @oneuse0(i8 %x, i8 %y) {

define i1 @oneuse1(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[RET:%.*]] = icmp uge i8 [[T1]], [[X:%.*]]
Expand All @@ -174,7 +174,7 @@ define i1 @oneuse1(i8 %x, i8 %y) {

define i1 @oneuse2(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
Expand All @@ -191,7 +191,7 @@ define i1 @oneuse2(i8 %x, i8 %y) {

define i1 @oneuse3(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse3(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -209,7 +209,7 @@ define i1 @oneuse3(i8 %x, i8 %y) {

define i1 @oneuse4(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse4(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand All @@ -228,7 +228,7 @@ define i1 @oneuse4(i8 %x, i8 %y) {

define i1 @oneuse5(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse5(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -253,7 +253,7 @@ define i1 @oneuse5(i8 %x, i8 %y) {

define i1 @n0(i8 %x, i8 %y, i8 %notx) {
; CHECK-LABEL: @n0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[NOTX:%.*]]
Expand Down Expand Up @@ -283,7 +283,7 @@ define i1 @n1(i8 %x, i8 %y) {

define i1 @n2(i8 %x, i8 %y) {
; CHECK-LABEL: @n2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], 1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
Expand Down
16 changes: 8 additions & 8 deletions llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v2-and-icmp-ne-to-icmp-ugt.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -142,7 +142,7 @@ declare void @use8(i8)

define i1 @oneuse0(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[X_HIGHBITS:%.*]] = lshr i8 [[X:%.*]], [[Y]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[X_HIGHBITS]], 0
Expand All @@ -158,7 +158,7 @@ define i1 @oneuse0(i8 %x, i8 %y) {

define i1 @oneuse1(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[RET:%.*]] = icmp ult i8 [[T1]], [[X:%.*]]
Expand All @@ -174,7 +174,7 @@ define i1 @oneuse1(i8 %x, i8 %y) {

define i1 @oneuse2(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
Expand All @@ -191,7 +191,7 @@ define i1 @oneuse2(i8 %x, i8 %y) {

define i1 @oneuse3(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse3(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -209,7 +209,7 @@ define i1 @oneuse3(i8 %x, i8 %y) {

define i1 @oneuse4(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse4(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand All @@ -228,7 +228,7 @@ define i1 @oneuse4(i8 %x, i8 %y) {

define i1 @oneuse5(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse5(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -253,7 +253,7 @@ define i1 @oneuse5(i8 %x, i8 %y) {

define i1 @n0(i8 %x, i8 %y, i8 %notx) {
; CHECK-LABEL: @n0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[NOTX:%.*]]
Expand Down Expand Up @@ -283,7 +283,7 @@ define i1 @n1(i8 %x, i8 %y) {

define i1 @n2(i8 %x, i8 %y) {
; CHECK-LABEL: @n2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T1:%.*]] = xor i8 [[T0]], 1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v3-and-icmp-eq-to-icmp-ule.ll
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Expand Up @@ -249,7 +249,7 @@ define i1 @n0(i8 %x, i8 %y, i8 %notx) {

define i1 @n1(i8 %x, i8 %y) {
; CHECK-LABEL: @n1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = add i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v3-and-icmp-ne-to-icmp-ugt.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -249,7 +249,7 @@ define i1 @n0(i8 %x, i8 %y, i8 %notx) {

define i1 @n1(i8 %x, i8 %y) {
; CHECK-LABEL: @n1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = add i8 [[T0]], -1
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand Down
20 changes: 10 additions & 10 deletions llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v4-and-icmp-eq-to-icmp-ule.ll
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Expand Up @@ -20,7 +20,7 @@ declare void @use3i8(<3 x i8>)

define i1 @p0(i8 %x, i8 %y) {
; CHECK-LABEL: @p0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[RET:%.*]] = icmp uge i8 [[T1]], [[X:%.*]]
Expand All @@ -40,7 +40,7 @@ define i1 @p0(i8 %x, i8 %y) {

define <2 x i1> @p1_vec(<2 x i8> %x, <2 x i8> %y) {
; CHECK-LABEL: @p1_vec(
; CHECK-NEXT: [[T0:%.*]] = shl <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: call void @use2i8(<2 x i8> [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact <2 x i8> [[T0]], [[Y]]
; CHECK-NEXT: [[RET:%.*]] = icmp uge <2 x i8> [[T1]], [[X:%.*]]
Expand Down Expand Up @@ -78,7 +78,7 @@ declare i8 @gen8()

define i1 @c0(i8 %y) {
; CHECK-LABEL: @c0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
Expand All @@ -96,7 +96,7 @@ define i1 @c0(i8 %y) {

define i1 @c1(i8 %y) {
; CHECK-LABEL: @c1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
Expand All @@ -114,7 +114,7 @@ define i1 @c1(i8 %y) {

define i1 @c2(i8 %y) {
; CHECK-LABEL: @c2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
Expand All @@ -136,7 +136,7 @@ define i1 @c2(i8 %y) {

define i1 @oneuse0(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -154,7 +154,7 @@ define i1 @oneuse0(i8 %x, i8 %y) {

define i1 @oneuse1(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse1(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand All @@ -173,7 +173,7 @@ define i1 @oneuse1(i8 %x, i8 %y) {

define i1 @oneuse2(i8 %x, i8 %y) {
; CHECK-LABEL: @oneuse2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[T1]])
Expand All @@ -198,7 +198,7 @@ define i1 @oneuse2(i8 %x, i8 %y) {

define i1 @n0(i8 %x, i8 %y, i8 %notx) {
; CHECK-LABEL: @n0(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr exact i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
Expand Down Expand Up @@ -230,7 +230,7 @@ define i1 @n1(i8 %x, i8 %y) {

define i1 @n2(i8 %x, i8 %y1, i8 %y2) {
; CHECK-LABEL: @n2(
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y1:%.*]]
; CHECK-NEXT: [[T0:%.*]] = shl nsw i8 -1, [[Y1:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y2:%.*]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
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