forked from OSchip/llvm-project
[InstCombine] Strip offset when folding and/or of icmps
When folding and/or of icmps, look through add of a constant and adjust the icmp range instead. Effectively, this decomposes X + C1 < C2 style range checks back into a normal range. This allows us to fold comparisons involving two range checks or one range check and some other condition. We had a fold for a really specific case of this (or of range check and eq, and only one one side!) while this handles it in fully generality. Differential Revision: https://reviews.llvm.org/D113510
This commit is contained in:
Nikita Popov
parent
fa1729067c
commit
58ebc79a64
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@ -1206,11 +1206,28 @@ static Value *foldAndOrOfICmpsUsingRanges(
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ICmpInst::Predicate Pred1, Value *V1, const APInt &C1,
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ICmpInst::Predicate Pred2, Value *V2, const APInt &C2,
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IRBuilderBase &Builder, bool IsAnd) {
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// Look through add of a constant offset on V1, V2, or both operands. This
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// allows us to interpret the V + C' < C'' range idiom into a proper range.
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const APInt *Offset1 = nullptr, *Offset2 = nullptr;
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if (V1 != V2) {
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Value *X;
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if (match(V1, m_Add(m_Value(X), m_APInt(Offset1))))
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V1 = X;
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if (match(V2, m_Add(m_Value(X), m_APInt(Offset2))))
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V2 = X;
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}
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if (V1 != V2)
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return nullptr;
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ConstantRange CR1 = ConstantRange::makeExactICmpRegion(Pred1, C1);
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if (Offset1)
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CR1 = CR1.subtract(*Offset1);
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ConstantRange CR2 = ConstantRange::makeExactICmpRegion(Pred2, C2);
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if (Offset2)
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CR2 = CR2.subtract(*Offset2);
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Optional<ConstantRange> CR =
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IsAnd ? CR1.exactIntersectWith(CR2) : CR1.exactUnionWith(CR2);
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if (!CR)
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@ -2464,15 +2481,6 @@ Value *InstCombinerImpl::foldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
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if (!LHSC || !RHSC)
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return nullptr;
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// (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ule (X + CA), C1)
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// iff C2 + CA == C1.
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if (PredL == ICmpInst::ICMP_ULT && PredR == ICmpInst::ICMP_EQ) {
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ConstantInt *AddC;
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if (match(LHS0, m_Add(m_Specific(RHS0), m_ConstantInt(AddC))))
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if (RHSC->getValue() + AddC->getValue() == LHSC->getValue())
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return Builder.CreateICmpULE(LHS0, LHSC);
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}
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return foldAndOrOfICmpsUsingRanges(PredL, LHS0, LHSC->getValue(),
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PredR, RHS0, RHSC->getValue(),
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Builder, /* IsAnd */ false);
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@ -1047,11 +1047,8 @@ define i1 @substitute_constant_or_ne_ule_use2_logical(i8 %x, i8 %y) {
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define i1 @or_ranges_overlap(i8 %x) {
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; CHECK-LABEL: @or_ranges_overlap(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[X]], -10
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; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP3]], 11
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; CHECK-NEXT: [[C7:%.*]] = or i1 [[TMP2]], [[TMP4]]
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; CHECK-NEXT: ret i1 [[C7]]
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 16
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1066,11 +1063,8 @@ define i1 @or_ranges_overlap(i8 %x) {
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define i1 @or_ranges_adjacent(i8 %x) {
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; CHECK-LABEL: @or_ranges_adjacent(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[X]], -11
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; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP3]], 10
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; CHECK-NEXT: [[C7:%.*]] = or i1 [[TMP2]], [[TMP4]]
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; CHECK-NEXT: ret i1 [[C7]]
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 16
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1117,11 +1111,9 @@ define i1 @or_ranges_single_elem_right(i8 %x) {
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define i1 @or_ranges_single_elem_left(i8 %x) {
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; CHECK-LABEL: @or_ranges_single_elem_left(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[C4:%.*]] = icmp eq i8 [[X]], 4
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; CHECK-NEXT: [[C6:%.*]] = or i1 [[TMP2]], [[C4]]
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; CHECK-NEXT: ret i1 [[C6]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -4
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 7
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1133,12 +1125,9 @@ define i1 @or_ranges_single_elem_left(i8 %x) {
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define i1 @and_ranges_overlap(i8 %x) {
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; CHECK-LABEL: @and_ranges_overlap(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[X]], -7
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; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP3]], 14
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; CHECK-NEXT: [[C7:%.*]] = and i1 [[TMP2]], [[TMP4]]
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; CHECK-NEXT: ret i1 [[C7]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -7
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 4
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1152,12 +1141,8 @@ define i1 @and_ranges_overlap(i8 %x) {
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define i1 @and_ranges_overlap_single(i8 %x) {
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; CHECK-LABEL: @and_ranges_overlap_single(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[X]], -10
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; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP3]], 11
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; CHECK-NEXT: [[C7:%.*]] = and i1 [[TMP2]], [[TMP4]]
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; CHECK-NEXT: ret i1 [[C7]]
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i8 [[X:%.*]], 10
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; CHECK-NEXT: ret i1 [[TMP1]]
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1171,12 +1156,7 @@ define i1 @and_ranges_overlap_single(i8 %x) {
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define i1 @and_ranges_no_overlap(i8 %x) {
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; CHECK-LABEL: @and_ranges_no_overlap(
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; CHECK-NEXT: [[TMP1:%.*]] = add i8 [[X:%.*]], -5
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], 6
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; CHECK-NEXT: [[TMP3:%.*]] = add i8 [[X]], -11
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; CHECK-NEXT: [[TMP4:%.*]] = icmp ult i8 [[TMP3]], 10
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; CHECK-NEXT: [[C7:%.*]] = and i1 [[TMP2]], [[TMP4]]
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; CHECK-NEXT: ret i1 [[C7]]
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; CHECK-NEXT: ret i1 false
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;
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%c1 = icmp uge i8 %x, 5
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%c2 = icmp ule i8 %x, 10
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@ -1190,12 +1170,9 @@ define i1 @and_ranges_no_overlap(i8 %x) {
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define i1 @and_ranges_signed_pred(i64 %x) {
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; CHECK-LABEL: @and_ranges_signed_pred(
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; CHECK-NEXT: [[T1:%.*]] = add i64 [[X:%.*]], 127
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; CHECK-NEXT: [[T2:%.*]] = icmp slt i64 [[T1]], 1024
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; CHECK-NEXT: [[T3:%.*]] = add i64 [[X]], 128
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; CHECK-NEXT: [[T4:%.*]] = icmp slt i64 [[T3]], 256
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; CHECK-NEXT: [[T5:%.*]] = and i1 [[T2]], [[T4]]
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; CHECK-NEXT: ret i1 [[T5]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i64 [[X:%.*]], -9223372036854775681
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i64 [[TMP1]], -9223372036854775553
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%t1 = add i64 %x, 127
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%t2 = icmp slt i64 %t1, 1024
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@ -537,11 +537,9 @@ define <2 x i1> @test37_undef(<2 x i32> %x) {
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define i1 @test38(i32 %x) {
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; CHECK-LABEL: @test38(
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[X:%.*]], 7
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; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[X]], 23
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; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[ADD1]], 30
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; CHECK-NEXT: [[RET1:%.*]] = or i1 [[CMP1]], [[CMP2]]
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; CHECK-NEXT: ret i1 [[RET1]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], 7
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], 31
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%add1 = add i32 %x, 7
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%cmp1 = icmp eq i32 %x, 23
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@ -552,11 +550,9 @@ define i1 @test38(i32 %x) {
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define i1 @test38_logical(i32 %x) {
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; CHECK-LABEL: @test38_logical(
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; CHECK-NEXT: [[ADD1:%.*]] = add i32 [[X:%.*]], 7
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; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[X]], 23
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; CHECK-NEXT: [[CMP2:%.*]] = icmp ult i32 [[ADD1]], 30
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; CHECK-NEXT: [[RET1:%.*]] = or i1 [[CMP1]], [[CMP2]]
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; CHECK-NEXT: ret i1 [[RET1]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], 7
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], 31
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%add1 = add i32 %x, 7
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%cmp1 = icmp eq i32 %x, 23
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@ -909,11 +909,8 @@ define i1 @negative_not_less_than_logical(i32 %arg) {
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define i1 @negative_not_power_of_two(i32 %arg) {
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; CHECK-LABEL: @negative_not_power_of_two(
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; CHECK-NEXT: [[T1:%.*]] = icmp sgt i32 [[ARG:%.*]], -1
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[ARG]], 255
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; CHECK-NEXT: [[T3:%.*]] = icmp ult i32 [[T2]], 256
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; CHECK-NEXT: [[T4:%.*]] = and i1 [[T1]], [[T3]]
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; CHECK-NEXT: ret i1 [[T4]]
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i32 [[ARG:%.*]], 0
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; CHECK-NEXT: ret i1 [[TMP1]]
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;
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%t1 = icmp sgt i32 %arg, -1
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%t2 = add i32 %arg, 255 ; should be power of two
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@ -924,11 +921,8 @@ define i1 @negative_not_power_of_two(i32 %arg) {
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define i1 @negative_not_power_of_two_logical(i32 %arg) {
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; CHECK-LABEL: @negative_not_power_of_two_logical(
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; CHECK-NEXT: [[T1:%.*]] = icmp sgt i32 [[ARG:%.*]], -1
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[ARG]], 255
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; CHECK-NEXT: [[T3:%.*]] = icmp ult i32 [[T2]], 256
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; CHECK-NEXT: [[T4:%.*]] = and i1 [[T1]], [[T3]]
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; CHECK-NEXT: ret i1 [[T4]]
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; CHECK-NEXT: [[TMP1:%.*]] = icmp eq i32 [[ARG:%.*]], 0
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; CHECK-NEXT: ret i1 [[TMP1]]
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;
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%t1 = icmp sgt i32 %arg, -1
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%t2 = add i32 %arg, 255 ; should be power of two
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@ -939,11 +933,8 @@ define i1 @negative_not_power_of_two_logical(i32 %arg) {
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define i1 @negative_not_next_power_of_two(i32 %arg) {
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; CHECK-LABEL: @negative_not_next_power_of_two(
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; CHECK-NEXT: [[T1:%.*]] = icmp sgt i32 [[ARG:%.*]], -1
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[ARG]], 64
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; CHECK-NEXT: [[T3:%.*]] = icmp ult i32 [[T2]], 256
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; CHECK-NEXT: [[T4:%.*]] = and i1 [[T1]], [[T3]]
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; CHECK-NEXT: ret i1 [[T4]]
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; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[ARG:%.*]], 192
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; CHECK-NEXT: ret i1 [[TMP1]]
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;
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%t1 = icmp sgt i32 %arg, -1
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%t2 = add i32 %arg, 64 ; should be 256 >> 1
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@ -954,11 +945,8 @@ define i1 @negative_not_next_power_of_two(i32 %arg) {
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define i1 @negative_not_next_power_of_two_logical(i32 %arg) {
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; CHECK-LABEL: @negative_not_next_power_of_two_logical(
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; CHECK-NEXT: [[T1:%.*]] = icmp sgt i32 [[ARG:%.*]], -1
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; CHECK-NEXT: [[T2:%.*]] = add i32 [[ARG]], 64
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; CHECK-NEXT: [[T3:%.*]] = icmp ult i32 [[T2]], 256
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; CHECK-NEXT: [[T4:%.*]] = and i1 [[T1]], [[T3]]
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; CHECK-NEXT: ret i1 [[T4]]
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; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[ARG:%.*]], 192
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; CHECK-NEXT: ret i1 [[TMP1]]
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;
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%t1 = icmp sgt i32 %arg, -1
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%t2 = add i32 %arg, 64 ; should be 256 >> 1
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@ -967,15 +955,11 @@ define i1 @negative_not_next_power_of_two_logical(i32 %arg) {
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ret i1 %t4
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}
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; I don't think this can be folded, at least not into single instruction.
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define i1 @two_signed_truncation_checks(i32 %arg) {
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; CHECK-LABEL: @two_signed_truncation_checks(
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[ARG:%.*]], 512
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; CHECK-NEXT: [[T2:%.*]] = icmp ult i32 [[T1]], 1024
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; CHECK-NEXT: [[T3:%.*]] = add i32 [[ARG]], 128
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; CHECK-NEXT: [[T4:%.*]] = icmp ult i32 [[T3]], 256
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; CHECK-NEXT: [[T5:%.*]] = and i1 [[T2]], [[T4]]
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; CHECK-NEXT: ret i1 [[T5]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[ARG:%.*]], 128
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], 256
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%t1 = add i32 %arg, 512
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%t2 = icmp ult i32 %t1, 1024
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@ -987,12 +971,9 @@ define i1 @two_signed_truncation_checks(i32 %arg) {
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define i1 @two_signed_truncation_checks_logical(i32 %arg) {
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; CHECK-LABEL: @two_signed_truncation_checks_logical(
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; CHECK-NEXT: [[T1:%.*]] = add i32 [[ARG:%.*]], 512
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; CHECK-NEXT: [[T2:%.*]] = icmp ult i32 [[T1]], 1024
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; CHECK-NEXT: [[T3:%.*]] = add i32 [[ARG]], 128
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; CHECK-NEXT: [[T4:%.*]] = icmp ult i32 [[T3]], 256
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; CHECK-NEXT: [[T5:%.*]] = and i1 [[T2]], [[T4]]
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; CHECK-NEXT: ret i1 [[T5]]
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; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[ARG:%.*]], 128
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; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i32 [[TMP1]], 256
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; CHECK-NEXT: ret i1 [[TMP2]]
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;
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%t1 = add i32 %arg, 512
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%t2 = icmp ult i32 %t1, 1024
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