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[InstCombine] Bail out on inner disjoint or in foldSelectICmpEq #121635

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[InstCombine] Bail out on inner disjoint or in foldSelectICmpEq #121635

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ee736a8
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Jan 4, 2025
3a704b6
[InstCombine] Bail out on inner disjoint or in `foldSelectICmpEq`
dtcxzyw Jan 4, 2025
38c15e0
cleanup
dtcxzyw Jan 4, 2025
4e1b6db
[InstCombine] Add more tests. NFC.
dtcxzyw Jan 4, 2025
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20 changes: 9 additions & 11 deletions llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1850,25 +1850,23 @@ static Instruction *foldSelectICmpEq(SelectInst &SI, ICmpInst *ICI,
return nullptr;

const unsigned AndOps = Instruction::And, OrOps = Instruction::Or,
XorOps = Instruction::Xor, NoOps = 0;
XorOps = Instruction::Xor;
enum NotMask { None = 0, NotInner, NotRHS };

// We cannot refine TrueVal to FalseVal when the inner instruction contains
// disjoint or.
auto matchFalseVal = [&](unsigned OuterOpc, unsigned InnerOpc,
unsigned NotMask) {
auto matchInner = m_c_BinOp(InnerOpc, m_Specific(X), m_Specific(Y));
if (OuterOpc == NoOps)
return match(CmpRHS, m_Zero()) && match(FalseVal, matchInner);

if (NotMask == NotInner) {
auto matchInner =
m_CombineAnd(m_c_BinOp(InnerOpc, m_Specific(X), m_Specific(Y)),
m_Unless(m_DisjointOr(m_Value(), m_Value())));
if (NotMask == NotInner)
return match(FalseVal, m_c_BinOp(OuterOpc, m_NotForbidPoison(matchInner),
m_Specific(CmpRHS)));
} else if (NotMask == NotRHS) {
if (NotMask == NotRHS)
return match(FalseVal, m_c_BinOp(OuterOpc, matchInner,
m_NotForbidPoison(m_Specific(CmpRHS))));
} else {
return match(FalseVal,
m_c_BinOp(OuterOpc, matchInner, m_Specific(CmpRHS)));
}
return match(FalseVal, m_c_BinOp(OuterOpc, matchInner, m_Specific(CmpRHS)));
};

// (X&Y)==C ? X|Y : X^Y -> (X^Y)|C : X^Y or (X^Y)^ C : X^Y
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78 changes: 78 additions & 0 deletions llvm/test/Transforms/InstCombine/select.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -4564,6 +4564,84 @@ define i32 @src_no_trans_select_xor_eq0_or_xor(i32 %x, i32 %y) {
ret i32 %cond
}

define i32 @src_no_trans_select_xor_eqc_and_disjoint_or_and_notc(i32 %x, i32 %y, i32 %c) {
; CHECK-LABEL: @src_no_trans_select_xor_eqc_and_disjoint_or_and_notc(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[XOR]], [[C:%.*]]
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X]], [[Y]]
; CHECK-NEXT: [[OR:%.*]] = or disjoint i32 [[Y]], [[X]]
; CHECK-NEXT: [[NOT:%.*]] = xor i32 [[C]], -1
; CHECK-NEXT: [[AND1:%.*]] = and i32 [[OR]], [[NOT]]
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[AND]], i32 [[AND1]]
; CHECK-NEXT: ret i32 [[COND]]
;
entry:
%xor = xor i32 %y, %x
%cmp = icmp eq i32 %xor, %c
%and = and i32 %x, %y
%or = or disjoint i32 %y, %x
%not = xor i32 %c, -1
%and1 = and i32 %or, %not
%cond = select i1 %cmp, i32 %and, i32 %and1
ret i32 %cond
}

define i32 @negative_inner_disjoint_or2(i32 %x, i32 %y, i32 %c) {
; CHECK-LABEL: @negative_inner_disjoint_or2(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[XOR:%.*]] = xor i32 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[XOR]], [[C:%.*]]
; CHECK-NEXT: [[AND:%.*]] = and i32 [[X]], [[Y]]
; CHECK-NEXT: [[OR:%.*]] = or disjoint i32 [[Y]], [[X]]
; CHECK-NEXT: [[AND1:%.*]] = xor i32 [[OR]], [[C]]
; CHECK-NEXT: [[COND:%.*]] = select i1 [[CMP]], i32 [[AND]], i32 [[AND1]]
; CHECK-NEXT: ret i32 [[COND]]
;
entry:
%xor = xor i32 %y, %x
%cmp = icmp eq i32 %xor, %c
%and = and i32 %x, %y
%or = or disjoint i32 %y, %x
%and1 = xor i32 %or, %c
%cond = select i1 %cmp, i32 %and, i32 %and1
ret i32 %cond
}

define i32 @positive_outer_disjoint_or1(i32 %x, i32 %y, i32 %c) {
; CHECK-LABEL: @positive_outer_disjoint_or1(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[AND:%.*]] = xor i32 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[OR1:%.*]] = or disjoint i32 [[AND]], [[C:%.*]]
; CHECK-NEXT: ret i32 [[OR1]]
;
entry:
%xor = and i32 %y, %x
%cmp = icmp eq i32 %xor, %c
%or = or i32 %y, %x
%and = xor i32 %y, %x
%or1 = or disjoint i32 %and, %c
%cond = select i1 %cmp, i32 %or, i32 %or1
ret i32 %cond
}

define i32 @positive_outer_disjoint_or2(i32 %x, i32 %y, i32 %c) {
; CHECK-LABEL: @positive_outer_disjoint_or2(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[AND:%.*]] = and i32 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[OR1:%.*]] = or disjoint i32 [[AND]], [[C:%.*]]
; CHECK-NEXT: ret i32 [[OR1]]
;
entry:
%xor = xor i32 %y, %x
%cmp = icmp eq i32 %xor, %c
%or = or i32 %y, %x
%and = and i32 %y, %x
%or1 = or disjoint i32 %and, %c
%cond = select i1 %cmp, i32 %or, i32 %or1
ret i32 %cond
}

; (X == C) ? X : Y -> (X == C) ? C : Y
; Fixed #77553
define i32 @src_select_xxory_eq0_xorxy_y(i32 %x, i32 %y) {
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