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[InstCombine] Reduce range of ctpop for non zero argument #100899

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Jul 29, 2024
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[InstCombine] Reduce range of ctpop for non zero argument #100899

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e113ae8
[InstCombine] Add pre-commit tests. NFC.
andjo403 Jul 27, 2024
5a671f5
[InstCombine] Reduce range of ctpop for non zero argument
andjo403 Jul 27, 2024
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24 changes: 18 additions & 6 deletions llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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Expand Up @@ -692,12 +692,24 @@ static Instruction *foldCtpop(IntrinsicInst &II, InstCombinerImpl &IC) {
Ty);

// Add range attribute since known bits can't completely reflect what we know.
if (BitWidth != 1 && !II.hasRetAttr(Attribute::Range) &&
!II.getMetadata(LLVMContext::MD_range)) {
ConstantRange Range(APInt(BitWidth, Known.countMinPopulation()),
APInt(BitWidth, Known.countMaxPopulation() + 1));
II.addRangeRetAttr(Range);
return ⅈ
if (BitWidth != 1) {
ConstantRange OldRange =
II.getRange().value_or(ConstantRange::getFull(BitWidth));

unsigned Lower = Known.countMinPopulation();
unsigned Upper = Known.countMaxPopulation() + 1;

if (Lower == 0 && OldRange.contains(APInt::getZero(BitWidth)) &&
isKnownNonZero(Op0, IC.getSimplifyQuery().getWithInstruction(&II)))
Lower = 1;

ConstantRange Range(APInt(BitWidth, Lower), APInt(BitWidth, Upper));
Range = Range.intersectWith(OldRange, ConstantRange::Unsigned);

if (Range != OldRange) {
II.addRangeRetAttr(Range);
return ⅈ
}
}

return nullptr;
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4 changes: 2 additions & 2 deletions llvm/test/Transforms/InstCombine/ctpop-pow2.ll
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Expand Up @@ -60,7 +60,7 @@ define i8 @ctpop_imin_plus1_lshr_nz(i8 %x) {
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[X:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: [[V:%.*]] = lshr i8 -127, [[X]]
; CHECK-NEXT: [[CNT:%.*]] = call range(i8 0, 9) i8 @llvm.ctpop.i8(i8 [[V]])
; CHECK-NEXT: [[CNT:%.*]] = call range(i8 1, 9) i8 @llvm.ctpop.i8(i8 [[V]])
; CHECK-NEXT: ret i8 [[CNT]]
;
%cmp = icmp ne i8 %x, 0
Expand Down Expand Up @@ -104,7 +104,7 @@ define <2 x i32> @ctpop_lshr_intmin_intmin_plus1_vec_nz(<2 x i32> %x) {
; CHECK-LABEL: @ctpop_lshr_intmin_intmin_plus1_vec_nz(
; CHECK-NEXT: [[X1:%.*]] = or <2 x i32> [[X:%.*]], <i32 1, i32 1>
; CHECK-NEXT: [[SHR:%.*]] = lshr <2 x i32> <i32 -2147483648, i32 -2147483647>, [[X1]]
; CHECK-NEXT: [[CNT:%.*]] = call range(i32 0, 17) <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[SHR]])
; CHECK-NEXT: [[CNT:%.*]] = call range(i32 1, 17) <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[SHR]])
; CHECK-NEXT: ret <2 x i32> [[CNT]]
;
%x1 = or <2 x i32> %x, <i32 1 ,i32 1>
Expand Down
22 changes: 20 additions & 2 deletions llvm/test/Transforms/InstCombine/ctpop.ll
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Expand Up @@ -169,8 +169,8 @@ define <2 x i32> @_parity_of_not_poison(<2 x i32> %x) {

define <2 x i32> @_parity_of_not_poison2(<2 x i32> %x) {
; CHECK-LABEL: @_parity_of_not_poison2(
; CHECK-NEXT: [[CNT:%.*]] = call range(i32 0, 33) <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
; CHECK-NEXT: [[R:%.*]] = and <2 x i32> [[CNT]], <i32 1, i32 poison>
; CHECK-NEXT: [[TMP1:%.*]] = call range(i32 0, 33) <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
; CHECK-NEXT: [[R:%.*]] = and <2 x i32> [[TMP1]], <i32 1, i32 poison>
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%neg = xor <2 x i32> %x, <i32 -1 ,i32 -1>
Expand Down Expand Up @@ -485,3 +485,21 @@ define i32 @select_ctpop_zero(i32 %x) {
%res = select i1 %cmp, i32 0, i32 %ctpop
ret i32 %res
}

define i32 @ctpop_non_zero(i32 range(i32 1, 255) %x) {
; CHECK-LABEL: @ctpop_non_zero(
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 1, 9) i32 @llvm.ctpop.i32(i32 [[X:%.*]])
; CHECK-NEXT: ret i32 [[CTPOP]]
;
%ctpop = call i32 @llvm.ctpop.i32(i32 %x)
ret i32 %ctpop
}

define i32 @ctpop_non_zero_with_existing_range_attr(i32 range(i32 1, 255) %x) {
; CHECK-LABEL: @ctpop_non_zero_with_existing_range_attr(
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 1, 9) i32 @llvm.ctpop.i32(i32 [[X:%.*]])
; CHECK-NEXT: ret i32 [[CTPOP]]
;
%ctpop = call range(i32 0, 9) i32 @llvm.ctpop.i32(i32 %x)
ret i32 %ctpop
}
4 changes: 2 additions & 2 deletions llvm/test/Transforms/InstCombine/icmp-ne-pow2.ll
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Expand Up @@ -306,7 +306,7 @@ define i32 @pow2_32_nonconst_assume(i32 %x, i32 %y) {

define i32 @pow2_32_gtnonconst_assume(i32 %x, i32 %y) {
; CHECK-LABEL: @pow2_32_gtnonconst_assume(
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[Y:%.*]])
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[Y:%.*]])
; CHECK-NEXT: [[YP2:%.*]] = icmp eq i32 [[CTPOP]], 1
; CHECK-NEXT: call void @llvm.assume(i1 [[YP2]])
; CHECK-NEXT: [[YGT:%.*]] = icmp ugt i32 [[Y]], [[X:%.*]]
Expand Down Expand Up @@ -513,7 +513,7 @@ define i32 @maybe_pow2_32_noncont(i32 %x, i32 %y) {
; CHECK-NEXT: [[YGT8:%.*]] = icmp ugt i32 [[Y:%.*]], 8
; CHECK-NEXT: br i1 [[YGT8]], label [[CONT1:%.*]], label [[CONT2:%.*]]
; CHECK: Cont1:
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[Y]])
; CHECK-NEXT: [[CTPOP:%.*]] = call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[Y]])
; CHECK-NEXT: [[YP2:%.*]] = icmp eq i32 [[CTPOP]], 1
; CHECK-NEXT: call void @llvm.assume(i1 [[YP2]])
; CHECK-NEXT: br i1 true, label [[CONT2]], label [[FALSE:%.*]]
Expand Down
8 changes: 4 additions & 4 deletions llvm/test/Transforms/InstCombine/ispow2.ll
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Expand Up @@ -197,7 +197,7 @@ define i1 @is_pow2_non_zero_ult_2(i32 %x) {
; CHECK-LABEL: @is_pow2_non_zero_ult_2(
; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i32 [[X:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[NOTZERO]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[T0]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
Expand All @@ -212,7 +212,7 @@ define i1 @is_pow2_non_zero_eq_1(i32 %x) {
; CHECK-LABEL: @is_pow2_non_zero_eq_1(
; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i32 [[X:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[NOTZERO]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[T0]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
Expand All @@ -227,7 +227,7 @@ define i1 @is_pow2_non_zero_ugt_1(i32 %x) {
; CHECK-LABEL: @is_pow2_non_zero_ugt_1(
; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i32 [[X:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[NOTZERO]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[T0]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
Expand All @@ -242,7 +242,7 @@ define i1 @is_pow2_non_zero_ne_1(i32 %x) {
; CHECK-LABEL: @is_pow2_non_zero_ne_1(
; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i32 [[X:%.*]], 0
; CHECK-NEXT: call void @llvm.assume(i1 [[NOTZERO]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[T0:%.*]] = tail call range(i32 1, 33) i32 @llvm.ctpop.i32(i32 [[X]])
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[T0]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
Expand Down
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