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[InstCombine] Add folds for (icmp eq/ne (and (add/sub/xor A, P2), P2), 0/P2) #67836

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[InstCombine] Add folds for (icmp eq/ne (and (add/sub/xor A, P2), P2), 0/P2) #67836

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c89ceea
[InstCombine] Add tests for folding (icmp eq/ne (and (add/sub/xor A, …
goldsteinn Sep 29, 2023
9e8f9fc
[InstCombine] Add folds for (icmp eq/ne (and (add/sub/xor A, P2), P2)…
goldsteinn Sep 29, 2023
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26 changes: 26 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5453,6 +5453,32 @@ Instruction *InstCombinerImpl::foldICmpEquality(ICmpInst &I) {
m_CombineAnd(m_Value(B), m_Unless(m_ImmConstant())))))
return new ICmpInst(Pred, Builder.CreateXor(A, B), Cst);

{
// (icmp eq/ne (and (add/sub/xor X, P2), P2), P2)
auto m_Matcher =
m_CombineOr(m_CombineOr(m_c_Add(m_Value(B), m_Deferred(A)),
m_c_Xor(m_Value(B), m_Deferred(A))),
m_Sub(m_Value(B), m_Deferred(A)));
std::optional<bool> IsZero = std::nullopt;
if (match(&I, m_c_ICmp(PredUnused, m_OneUse(m_c_And(m_Value(A), m_Matcher)),
m_Deferred(A))))
IsZero = false;
// (icmp eq/ne (and (add/sub/xor X, P2), P2), 0)
else if (match(&I,
m_ICmp(PredUnused, m_OneUse(m_c_And(m_Value(A), m_Matcher)),
m_Zero())))
IsZero = true;

if (IsZero && isKnownToBeAPowerOfTwo(A, /* OrZero */ true, /*Depth*/ 0, &I))
// (icmp eq/ne (and (add/sub/xor X, P2), P2), P2)
// -> (icmp eq/ne (and X, P2), 0)
// (icmp eq/ne (and (add/sub/xor X, P2), P2), 0)
// -> (icmp eq/ne (and X, P2), P2)
return new ICmpInst(Pred, Builder.CreateAnd(B, A),
*IsZero ? A
: ConstantInt::getNullValue(A->getType()));
}

return nullptr;
}

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154 changes: 154 additions & 0 deletions llvm/test/Transforms/InstCombine/icmp-and-add-sub-xor-p2.ll
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@@ -0,0 +1,154 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=instcombine -S -o - %s | FileCheck %s

declare void @use.i8(i8)
declare void @use.v2i8(<2 x i8>)
define i1 @src_add_eq_p2(i8 %x, i8 %yy) {
; CHECK-LABEL: @src_add_eq_p2(
; CHECK-NEXT: [[NY:%.*]] = sub i8 0, [[YY:%.*]]
; CHECK-NEXT: [[Y:%.*]] = and i8 [[NY]], [[YY]]
; CHECK-NEXT: [[X1:%.*]] = add i8 [[Y]], [[X:%.*]]
; CHECK-NEXT: call void @use.i8(i8 [[X1]])
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[Y]], [[X]]
; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[TMP1]], 0
; CHECK-NEXT: ret i1 [[R]]
;
%ny = sub i8 0, %yy
%y = and i8 %ny, %yy
%x1 = add i8 %y, %x
call void @use.i8(i8 %x1)
%v = and i8 %x1, %y
%r = icmp eq i8 %v, %y
ret i1 %r
}

define i1 @src_add_eq_p2_fail_multiuse(i8 %x, i8 %yy) {
; CHECK-LABEL: @src_add_eq_p2_fail_multiuse(
; CHECK-NEXT: [[NY:%.*]] = sub i8 0, [[YY:%.*]]
; CHECK-NEXT: [[Y:%.*]] = and i8 [[NY]], [[YY]]
; CHECK-NEXT: [[X1:%.*]] = add i8 [[Y]], [[X:%.*]]
; CHECK-NEXT: call void @use.i8(i8 [[X1]])
; CHECK-NEXT: [[V:%.*]] = and i8 [[X1]], [[Y]]
; CHECK-NEXT: call void @use.i8(i8 [[V]])
; CHECK-NEXT: [[R:%.*]] = icmp eq i8 [[V]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
;
%ny = sub i8 0, %yy
%y = and i8 %ny, %yy
%x1 = add i8 %x, %y
call void @use.i8(i8 %x1)
%v = and i8 %x1, %y
call void @use.i8(i8 %v)
%r = icmp eq i8 %v, %y
ret i1 %r
}

define i1 @src_xor_ne_zero(i8 %x, i8 %yy) {
; CHECK-LABEL: @src_xor_ne_zero(
; CHECK-NEXT: [[NY:%.*]] = sub i8 0, [[YY:%.*]]
; CHECK-NEXT: [[Y:%.*]] = and i8 [[NY]], [[YY]]
; CHECK-NEXT: [[X1:%.*]] = xor i8 [[Y]], [[X:%.*]]
; CHECK-NEXT: call void @use.i8(i8 [[X1]])
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[Y]], [[X]]
; CHECK-NEXT: [[R:%.*]] = icmp ne i8 [[TMP1]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
;
%ny = sub i8 0, %yy
%y = and i8 %ny, %yy
%x1 = xor i8 %x, %y
call void @use.i8(i8 %x1)
%v = and i8 %x1, %y
%r = icmp ne i8 %v, 0
ret i1 %r
}

define i1 @src_xor_ne_zero_fail_different_p2(i8 %x, i8 %yy) {
; CHECK-LABEL: @src_xor_ne_zero_fail_different_p2(
; CHECK-NEXT: [[NY:%.*]] = sub i8 0, [[YY:%.*]]
; CHECK-NEXT: [[Y:%.*]] = and i8 [[NY]], [[YY]]
; CHECK-NEXT: [[Y2:%.*]] = shl i8 [[Y]], 1
; CHECK-NEXT: [[X1:%.*]] = xor i8 [[Y]], [[X:%.*]]
; CHECK-NEXT: call void @use.i8(i8 [[X1]])
; CHECK-NEXT: [[V:%.*]] = and i8 [[X1]], [[Y2]]
; CHECK-NEXT: [[R:%.*]] = icmp ne i8 [[V]], 0
; CHECK-NEXT: ret i1 [[R]]
;
%ny = sub i8 0, %yy
%y = and i8 %ny, %yy
%y2 = shl i8 %y, 1
%x1 = xor i8 %x, %y
call void @use.i8(i8 %x1)
%v = and i8 %x1, %y2
%r = icmp ne i8 %v, 0
ret i1 %r
}

define <2 x i1> @src_sub_ne_p2(<2 x i8> %x, <2 x i8> %yy) {
; CHECK-LABEL: @src_sub_ne_p2(
; CHECK-NEXT: [[NY:%.*]] = sub <2 x i8> zeroinitializer, [[YY:%.*]]
; CHECK-NEXT: [[Y:%.*]] = and <2 x i8> [[NY]], [[YY]]
; CHECK-NEXT: [[X1:%.*]] = sub <2 x i8> [[X:%.*]], [[Y]]
; CHECK-NEXT: call void @use.v2i8(<2 x i8> [[X1]])
; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[Y]], [[X]]
; CHECK-NEXT: [[R:%.*]] = icmp ne <2 x i8> [[TMP1]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%ny = sub <2 x i8> zeroinitializer, %yy
%y = and <2 x i8> %ny, %yy
%x1 = sub <2 x i8> %x, %y
call void @use.v2i8(<2 x i8> %x1)
%v = and <2 x i8> %x1, %y
%r = icmp ne <2 x i8> %v, %y
ret <2 x i1> %r
}

define <2 x i1> @src_sub_eq_zero(<2 x i8> %x, <2 x i8> %yy) {
; CHECK-LABEL: @src_sub_eq_zero(
; CHECK-NEXT: [[Y:%.*]] = shl <2 x i8> <i8 1, i8 2>, [[YY:%.*]]
; CHECK-NEXT: [[X1:%.*]] = sub <2 x i8> [[X:%.*]], [[Y]]
; CHECK-NEXT: call void @use.v2i8(<2 x i8> [[X1]])
; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[Y]], [[X]]
; CHECK-NEXT: [[R:%.*]] = icmp eq <2 x i8> [[TMP1]], [[Y]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%y = shl <2 x i8> <i8 1, i8 2>, %yy
%x1 = sub <2 x i8> %x, %y
call void @use.v2i8(<2 x i8> %x1)
%v = and <2 x i8> %x1, %y
%r = icmp eq <2 x i8> %v, zeroinitializer
ret <2 x i1> %r
}

define <2 x i1> @src_sub_eq_zero_fail_commuted(<2 x i8> %x, <2 x i8> %yy) {
; CHECK-LABEL: @src_sub_eq_zero_fail_commuted(
; CHECK-NEXT: [[Y:%.*]] = shl <2 x i8> <i8 1, i8 2>, [[YY:%.*]]
; CHECK-NEXT: [[X1:%.*]] = sub <2 x i8> [[Y]], [[X:%.*]]
; CHECK-NEXT: call void @use.v2i8(<2 x i8> [[X1]])
; CHECK-NEXT: [[V:%.*]] = and <2 x i8> [[X1]], [[Y]]
; CHECK-NEXT: [[R:%.*]] = icmp eq <2 x i8> [[V]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%y = shl <2 x i8> <i8 1, i8 2>, %yy
%x1 = sub <2 x i8> %y, %x
call void @use.v2i8(<2 x i8> %x1)
%v = and <2 x i8> %x1, %y
%r = icmp eq <2 x i8> %v, zeroinitializer
ret <2 x i1> %r
}

define <2 x i1> @src_sub_eq_zero_fail_non_p2(<2 x i8> %x, <2 x i8> %yy) {
; CHECK-LABEL: @src_sub_eq_zero_fail_non_p2(
; CHECK-NEXT: [[Y:%.*]] = shl <2 x i8> <i8 1, i8 3>, [[YY:%.*]]
; CHECK-NEXT: [[X1:%.*]] = sub <2 x i8> [[X:%.*]], [[Y]]
; CHECK-NEXT: call void @use.v2i8(<2 x i8> [[X1]])
; CHECK-NEXT: [[V:%.*]] = and <2 x i8> [[X1]], [[Y]]
; CHECK-NEXT: [[R:%.*]] = icmp eq <2 x i8> [[V]], zeroinitializer
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%y = shl <2 x i8> <i8 1, i8 3>, %yy
%x1 = sub <2 x i8> %x, %y
call void @use.v2i8(<2 x i8> %x1)
%v = and <2 x i8> %x1, %y
%r = icmp eq <2 x i8> %v, zeroinitializer
ret <2 x i1> %r
}
12 changes: 6 additions & 6 deletions llvm/test/Transforms/InstCombine/pr25342.ll
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Expand Up @@ -78,7 +78,7 @@ define void @multi_phi(i32 signext %n) {
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[FOR_COND:%.*]]
; CHECK: for.cond:
; CHECK-NEXT: [[TMP0:%.*]] = phi float [ 0.000000e+00, [[ENTRY:%.*]] ], [ [[TMP6:%.*]], [[ODD_BB:%.*]] ]
; CHECK-NEXT: [[TMP0:%.*]] = phi float [ 0.000000e+00, [[ENTRY:%.*]] ], [ [[TMP7:%.*]], [[ODD_BB:%.*]] ]
; CHECK-NEXT: [[I_0:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[INC:%.*]], [[ODD_BB]] ]
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[I_0]], [[N:%.*]]
; CHECK-NEXT: br i1 [[CMP]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
Expand All @@ -92,14 +92,14 @@ define void @multi_phi(i32 signext %n) {
; CHECK-NEXT: [[SUB_I:%.*]] = fsub float [[MUL_I]], [[MUL4_I]]
; CHECK-NEXT: [[ADD_I:%.*]] = fadd float [[SUB_I]], [[TMP0]]
; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[I_0]], 1
; CHECK-NEXT: [[BIT0:%.*]] = and i32 [[INC]], 1
; CHECK-NEXT: [[EVEN_NOT_NOT:%.*]] = icmp eq i32 [[BIT0]], 0
; CHECK-NEXT: br i1 [[EVEN_NOT_NOT]], label [[EVEN_BB:%.*]], label [[ODD_BB]]
; CHECK-NEXT: [[TMP5:%.*]] = and i32 [[I_0]], 1
; CHECK-NEXT: [[EVEN_NOT_NOT_NOT:%.*]] = icmp eq i32 [[TMP5]], 0
; CHECK-NEXT: br i1 [[EVEN_NOT_NOT_NOT]], label [[ODD_BB]], label [[EVEN_BB:%.*]]
; CHECK: even.bb:
; CHECK-NEXT: [[TMP5:%.*]] = fadd float [[SUB_I]], [[ADD_I]]
; CHECK-NEXT: [[TMP6:%.*]] = fadd float [[SUB_I]], [[ADD_I]]
; CHECK-NEXT: br label [[ODD_BB]]
; CHECK: odd.bb:
; CHECK-NEXT: [[TMP6]] = phi float [ [[ADD_I]], [[FOR_BODY]] ], [ [[TMP5]], [[EVEN_BB]] ]
; CHECK-NEXT: [[TMP7]] = phi float [ [[ADD_I]], [[FOR_BODY]] ], [ [[TMP6]], [[EVEN_BB]] ]
; CHECK-NEXT: br label [[FOR_COND]]
; CHECK: for.end:
; CHECK-NEXT: store float [[TMP0]], ptr @dd, align 4
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2 changes: 1 addition & 1 deletion llvm/test/Transforms/PGOProfile/cspgo_profile_summary.ll
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Expand Up @@ -104,7 +104,7 @@ for.end:
; CSPGOSUMMARY-LABEL: @foo
; CSPGOSUMMARY: %even.odd.i = select i1 %tobool.i{{[0-9]*}}, ptr @even, ptr @odd
; CSPGOSUMMARY-SAME: !prof ![[BW_CSPGO_BAR]]
; CSPGOSUMMARY: %even.odd.i2 = select i1 %tobool.i{{[0-9]*}}, ptr @even, ptr @odd
; CSPGOSUMMARY: %even.odd.i2 = select i1 %tobool.i{{[0-9]*}}, ptr @odd, ptr @even
; CSPGOSUMMARY-SAME: !prof ![[BW_CSPGO_BAR]]

declare dso_local i32 @bar_m(i32)
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