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Dec 5, 2023
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[InstCombine] Check isGuaranteedNotToBeUndef in haveNoCommonBitsSetSp… #74390

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62811ae
[InstCombine] Check isGuaranteedNotToBeUndef in haveNoCommonBitsSetSp…
topperc Dec 4, 2023
ba5f9eb
fixup! clang-format
topperc Dec 5, 2023
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26 changes: 17 additions & 9 deletions llvm/lib/Analysis/ValueTracking.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -186,37 +186,45 @@ KnownBits llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
}

static bool haveNoCommonBitsSetSpecialCases(const Value *LHS,
const Value *RHS) {
static bool haveNoCommonBitsSetSpecialCases(const Value *LHS, const Value *RHS,
const SimplifyQuery &SQ) {
// Look for an inverted mask: (X & ~M) op (Y & M).
{
Value *M;
if (match(LHS, m_c_And(m_Not(m_Value(M)), m_Value())) &&
match(RHS, m_c_And(m_Specific(M), m_Value())))
match(RHS, m_c_And(m_Specific(M), m_Value())) &&
isGuaranteedNotToBeUndef(M, SQ.AC, SQ.CxtI, SQ.DT))
return true;
}

// X op (Y & ~X)
if (match(RHS, m_c_And(m_Not(m_Specific(LHS)), m_Value())))
if (match(RHS, m_c_And(m_Not(m_Specific(LHS)), m_Value())) &&
isGuaranteedNotToBeUndef(LHS, SQ.AC, SQ.CxtI, SQ.DT))
return true;

// X op ((X & Y) ^ Y) -- this is the canonical form of the previous pattern
// for constant Y.
Value *Y;
if (match(RHS, m_c_Xor(m_c_And(m_Specific(LHS), m_Value(Y)), m_Deferred(Y))))
if (match(RHS,
m_c_Xor(m_c_And(m_Specific(LHS), m_Value(Y)), m_Deferred(Y))) &&
isGuaranteedNotToBeUndef(LHS, SQ.AC, SQ.CxtI, SQ.DT) &&
isGuaranteedNotToBeUndef(Y, SQ.AC, SQ.CxtI, SQ.DT))
return true;

// Peek through extends to find a 'not' of the other side:
// (ext Y) op ext(~Y)
if (match(LHS, m_ZExtOrSExt(m_Value(Y))) &&
match(RHS, m_ZExtOrSExt(m_Not(m_Specific(Y)))))
match(RHS, m_ZExtOrSExt(m_Not(m_Specific(Y)))) &&
isGuaranteedNotToBeUndef(Y, SQ.AC, SQ.CxtI, SQ.DT))
return true;

// Look for: (A & B) op ~(A | B)
{
Value *A, *B;
if (match(LHS, m_And(m_Value(A), m_Value(B))) &&
match(RHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))))
match(RHS, m_Not(m_c_Or(m_Specific(A), m_Specific(B)))) &&
isGuaranteedNotToBeUndef(A, SQ.AC, SQ.CxtI, SQ.DT) &&
isGuaranteedNotToBeUndef(B, SQ.AC, SQ.CxtI, SQ.DT))
return true;
}

Expand All @@ -234,8 +242,8 @@ bool llvm::haveNoCommonBitsSet(const WithCache<const Value *> &LHSCache,
assert(LHS->getType()->isIntOrIntVectorTy() &&
"LHS and RHS should be integers");

if (haveNoCommonBitsSetSpecialCases(LHS, RHS) ||
haveNoCommonBitsSetSpecialCases(RHS, LHS))
if (haveNoCommonBitsSetSpecialCases(LHS, RHS, SQ) ||
haveNoCommonBitsSetSpecialCases(RHS, LHS, SQ))
return true;

return KnownBits::haveNoCommonBitsSet(LHSCache.getKnownBits(SQ),
Expand Down
46 changes: 23 additions & 23 deletions llvm/test/Transforms/InstCombine/add.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -1521,7 +1521,7 @@ define i8 @add_like_or_disjoint(i8 %x) {
ret i8 %r
}

define i8 @add_and_xor(i8 %x, i8 %y) {
define i8 @add_and_xor(i8 noundef %x, i8 %y) {
; CHECK-LABEL: @add_and_xor(
; CHECK-NEXT: [[ADD:%.*]] = or i8 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: ret i8 [[ADD]]
Expand Down Expand Up @@ -1558,7 +1558,7 @@ define i8 @add_and_xor_wrong_op(i8 %x, i8 %y, i8 %z) {
ret i8 %add
}

define i8 @add_and_xor_commuted1(i8 %x, i8 %_y) {
define i8 @add_and_xor_commuted1(i8 noundef %x, i8 %_y) {
; CHECK-LABEL: @add_and_xor_commuted1(
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
; CHECK-NEXT: [[ADD:%.*]] = or i8 [[Y]], [[X:%.*]]
Expand All @@ -1571,7 +1571,7 @@ define i8 @add_and_xor_commuted1(i8 %x, i8 %_y) {
ret i8 %add
}

define i8 @add_and_xor_commuted2(i8 %_x, i8 %y) {
define i8 @add_and_xor_commuted2(i8 noundef %_x, i8 %y) {
; CHECK-LABEL: @add_and_xor_commuted2(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[ADD:%.*]] = or i8 [[X]], [[Y:%.*]]
Expand All @@ -1584,7 +1584,7 @@ define i8 @add_and_xor_commuted2(i8 %_x, i8 %y) {
ret i8 %add
}

define i8 @add_and_xor_commuted3(i8 %_x, i8 %_y) {
define i8 @add_and_xor_commuted3(i8 noundef %_x, i8 %_y) {
; CHECK-LABEL: @add_and_xor_commuted3(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
Expand All @@ -1599,7 +1599,7 @@ define i8 @add_and_xor_commuted3(i8 %_x, i8 %_y) {
ret i8 %add
}

define i8 @add_and_xor_extra_use(i8 %x, i8 %y) {
define i8 @add_and_xor_extra_use(i8 noundef %x, i8 %y) {
; CHECK-LABEL: @add_and_xor_extra_use(
; CHECK-NEXT: [[XOR:%.*]] = xor i8 [[X:%.*]], -1
; CHECK-NEXT: call void @use(i8 [[XOR]])
Expand All @@ -1616,7 +1616,7 @@ define i8 @add_and_xor_extra_use(i8 %x, i8 %y) {
ret i8 %add
}

define i8 @add_xor_and_const(i8 %x) {
define i8 @add_xor_and_const(i8 noundef %x) {
; CHECK-LABEL: @add_xor_and_const(
; CHECK-NEXT: [[ADD:%.*]] = or i8 [[X:%.*]], 42
; CHECK-NEXT: ret i8 [[ADD]]
Expand All @@ -1640,7 +1640,7 @@ define i8 @add_xor_and_const_wrong_const(i8 %x) {
ret i8 %add
}

define i8 @add_xor_and_var(i8 %x, i8 %y) {
define i8 @add_xor_and_var(i8 noundef %x, i8 noundef %y) {
; CHECK-LABEL: @add_xor_and_var(
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use(i8 [[AND]])
Expand Down Expand Up @@ -1684,7 +1684,7 @@ define i8 @add_xor_and_var_wrong_op2(i8 %x, i8 %y, i8 %z) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted1(i8 %x, i8 %y) {
define i8 @add_xor_and_var_commuted1(i8 noundef %x, i8 noundef %y) {
; CHECK-LABEL: @add_xor_and_var_commuted1(
; CHECK-NEXT: [[AND:%.*]] = and i8 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: call void @use(i8 [[AND]])
Expand All @@ -1698,7 +1698,7 @@ define i8 @add_xor_and_var_commuted1(i8 %x, i8 %y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted2(i8 %_x, i8 %_y) {
define i8 @add_xor_and_var_commuted2(i8 noundef %_x, i8 noundef %_y) {
; CHECK-LABEL: @add_xor_and_var_commuted2(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
Expand All @@ -1716,7 +1716,7 @@ define i8 @add_xor_and_var_commuted2(i8 %_x, i8 %_y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted3(i8 %x, i8 %_y) {
define i8 @add_xor_and_var_commuted3(i8 noundef %x, i8 noundef %_y) {
; CHECK-LABEL: @add_xor_and_var_commuted3(
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
; CHECK-NEXT: [[AND:%.*]] = and i8 [[Y]], [[X:%.*]]
Expand All @@ -1732,7 +1732,7 @@ define i8 @add_xor_and_var_commuted3(i8 %x, i8 %_y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted4(i8 %_x, i8 %y) {
define i8 @add_xor_and_var_commuted4(i8 noundef %_x, i8 noundef %y) {
; CHECK-LABEL: @add_xor_and_var_commuted4(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Y:%.*]]
Expand All @@ -1748,7 +1748,7 @@ define i8 @add_xor_and_var_commuted4(i8 %_x, i8 %y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted5(i8 %_x, i8 %_y) {
define i8 @add_xor_and_var_commuted5(i8 noundef %_x, i8 noundef %_y) {
; CHECK-LABEL: @add_xor_and_var_commuted5(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
Expand All @@ -1766,7 +1766,7 @@ define i8 @add_xor_and_var_commuted5(i8 %_x, i8 %_y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted6(i8 %_x, i8 %_y) {
define i8 @add_xor_and_var_commuted6(i8 noundef %_x, i8 noundef %_y) {
; CHECK-LABEL: @add_xor_and_var_commuted6(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
Expand All @@ -1784,7 +1784,7 @@ define i8 @add_xor_and_var_commuted6(i8 %_x, i8 %_y) {
ret i8 %add
}

define i8 @add_xor_and_var_commuted7(i8 %_x, i8 %_y) {
define i8 @add_xor_and_var_commuted7(i8 noundef %_x, i8 noundef %_y) {
; CHECK-LABEL: @add_xor_and_var_commuted7(
; CHECK-NEXT: [[X:%.*]] = udiv i8 42, [[_X:%.*]]
; CHECK-NEXT: [[Y:%.*]] = udiv i8 42, [[_Y:%.*]]
Expand All @@ -1802,7 +1802,7 @@ define i8 @add_xor_and_var_commuted7(i8 %_x, i8 %_y) {
ret i8 %add
}

define i8 @add_xor_and_var_extra_use(i8 %x, i8 %y) {
define i8 @add_xor_and_var_extra_use(i8 noundef %x, i8 noundef %y) {
; CHECK-LABEL: @add_xor_and_var_extra_use(
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: call void @use(i8 [[AND]])
Expand Down Expand Up @@ -2583,7 +2583,7 @@ define <vscale x 1 x i32> @add_to_or_scalable(<vscale x 1 x i32> %in) {
ret <vscale x 1 x i32> %add
}

define i5 @zext_zext_not(i3 %x) {
define i5 @zext_zext_not(i3 noundef %x) {
; CHECK-LABEL: @zext_zext_not(
; CHECK-NEXT: ret i5 7
;
Expand All @@ -2594,7 +2594,7 @@ define i5 @zext_zext_not(i3 %x) {
ret i5 %r
}

define <2 x i5> @zext_zext_not_commute(<2 x i3> %x) {
define <2 x i5> @zext_zext_not_commute(<2 x i3> noundef %x) {
; CHECK-LABEL: @zext_zext_not_commute(
; CHECK-NEXT: ret <2 x i5> <i5 7, i5 7>
;
Expand All @@ -2605,7 +2605,7 @@ define <2 x i5> @zext_zext_not_commute(<2 x i3> %x) {
ret <2 x i5> %r
}

define i9 @sext_sext_not(i3 %x) {
define i9 @sext_sext_not(i3 noundef %x) {
; CHECK-LABEL: @sext_sext_not(
; CHECK-NEXT: ret i9 -1
;
Expand All @@ -2616,7 +2616,7 @@ define i9 @sext_sext_not(i3 %x) {
ret i9 %r
}

define i8 @sext_sext_not_commute(i3 %x) {
define i8 @sext_sext_not_commute(i3 noundef %x) {
; CHECK-LABEL: @sext_sext_not_commute(
; CHECK-NEXT: [[SX:%.*]] = sext i3 [[X:%.*]] to i8
; CHECK-NEXT: call void @use(i8 [[SX]])
Expand All @@ -2631,7 +2631,7 @@ define i8 @sext_sext_not_commute(i3 %x) {
ret i8 %r
}

define i5 @zext_sext_not(i4 %x) {
define i5 @zext_sext_not(i4 noundef %x) {
; CHECK-LABEL: @zext_sext_not(
; CHECK-NEXT: [[ZX:%.*]] = zext i4 [[X:%.*]] to i5
; CHECK-NEXT: [[NOTX:%.*]] = xor i4 [[X]], -1
Expand All @@ -2646,7 +2646,7 @@ define i5 @zext_sext_not(i4 %x) {
ret i5 %r
}

define i8 @zext_sext_not_commute(i4 %x) {
define i8 @zext_sext_not_commute(i4 noundef %x) {
; CHECK-LABEL: @zext_sext_not_commute(
; CHECK-NEXT: [[ZX:%.*]] = zext i4 [[X:%.*]] to i8
; CHECK-NEXT: call void @use(i8 [[ZX]])
Expand All @@ -2665,7 +2665,7 @@ define i8 @zext_sext_not_commute(i4 %x) {
ret i8 %r
}

define i9 @sext_zext_not(i4 %x) {
define i9 @sext_zext_not(i4 noundef %x) {
; CHECK-LABEL: @sext_zext_not(
; CHECK-NEXT: [[SX:%.*]] = sext i4 [[X:%.*]] to i9
; CHECK-NEXT: [[NOTX:%.*]] = xor i4 [[X]], -1
Expand All @@ -2680,7 +2680,7 @@ define i9 @sext_zext_not(i4 %x) {
ret i9 %r
}

define i9 @sext_zext_not_commute(i4 %x) {
define i9 @sext_zext_not_commute(i4 noundef %x) {
; CHECK-LABEL: @sext_zext_not_commute(
; CHECK-NEXT: [[SX:%.*]] = sext i4 [[X:%.*]] to i9
; CHECK-NEXT: [[NOTX:%.*]] = xor i4 [[X]], -1
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/Transforms/InstCombine/and-or-not.ll
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Expand Up @@ -548,7 +548,7 @@ define i32 @and_to_nxor_multiuse(float %fa, float %fb) {

; (a & b) | ~(a | b) --> ~(a ^ b)
; TODO: this increases instruction count if the pieces have additional users
define i32 @or_to_nxor_multiuse(i32 %a, i32 %b) {
define i32 @or_to_nxor_multiuse(i32 noundef %a, i32 noundef %b) {
; CHECK-LABEL: @or_to_nxor_multiuse(
; CHECK-NEXT: [[AND:%.*]] = and i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[OR:%.*]] = or i32 [[A]], [[B]]
Expand Down
6 changes: 3 additions & 3 deletions llvm/test/Transforms/InstCombine/logical-select.ll
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Expand Up @@ -762,7 +762,7 @@ define <vscale x 2 x i64> @bitcast_vec_cond_scalable(<vscale x 16 x i1> %cond, <

; Negative test - bitcast of condition from wide source element type cannot be converted to select.

define <8 x i3> @bitcast_vec_cond_commute1(<3 x i1> %cond, <8 x i3> %pc, <8 x i3> %d) {
define <8 x i3> @bitcast_vec_cond_commute1(<3 x i1> noundef %cond, <8 x i3> %pc, <8 x i3> %d) {
; CHECK-LABEL: @bitcast_vec_cond_commute1(
; CHECK-NEXT: [[C:%.*]] = mul <8 x i3> [[PC:%.*]], [[PC]]
; CHECK-NEXT: [[S:%.*]] = sext <3 x i1> [[COND:%.*]] to <3 x i8>
Expand Down Expand Up @@ -830,7 +830,7 @@ define <2 x i16> @bitcast_vec_cond_commute3(<4 x i8> %cond, <2 x i16> %pc, <2 x

; Don't crash on invalid type for compute signbits.

define <2 x i64> @bitcast_fp_vec_cond(<2 x double> %s, <2 x i64> %c, <2 x i64> %d) {
define <2 x i64> @bitcast_fp_vec_cond(<2 x double> noundef %s, <2 x i64> %c, <2 x i64> %d) {
; CHECK-LABEL: @bitcast_fp_vec_cond(
; CHECK-NEXT: [[T9:%.*]] = bitcast <2 x double> [[S:%.*]] to <2 x i64>
; CHECK-NEXT: [[NOTT9:%.*]] = xor <2 x i64> [[T9]], <i64 -1, i64 -1>
Expand All @@ -849,7 +849,7 @@ define <2 x i64> @bitcast_fp_vec_cond(<2 x double> %s, <2 x i64> %c, <2 x i64> %

; Wider source type would be ok except poison could leak across elements.

define <2 x i64> @bitcast_int_vec_cond(i1 %b, <2 x i64> %c, <2 x i64> %d) {
define <2 x i64> @bitcast_int_vec_cond(i1 noundef %b, <2 x i64> %c, <2 x i64> %d) {
; CHECK-LABEL: @bitcast_int_vec_cond(
; CHECK-NEXT: [[S:%.*]] = sext i1 [[B:%.*]] to i128
; CHECK-NEXT: [[T9:%.*]] = bitcast i128 [[S]] to <2 x i64>
Expand Down
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