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[LVI] Infer non-zero from equality icmp #112838

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Merged
merged 3 commits into from
Oct 18, 2024
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[LVI] Infer non-zero from equality icmp #112838

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c34c8f9
[CVP] Add pre-commit tests. NFC.
dtcxzyw Oct 18, 2024
cee2b09
[LVI] Infer non-zero from equality icmp
dtcxzyw Oct 18, 2024
2c3e039
[LVI] Address review comments.
dtcxzyw Oct 18, 2024
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14 changes: 14 additions & 0 deletions llvm/lib/Analysis/LazyValueInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1188,6 +1188,20 @@ std::optional<ValueLatticeElement> LazyValueInfoImpl::getValueFromICmpCondition(
return ValueLatticeElement::getRange(*CR);
}

// a - b or ptrtoint(a) - ptrtoint(b) ==/!= 0 if a ==/!= b
Value *X, *Y;
if (ICI->isEquality() && match(Val, m_Sub(m_Value(X), m_Value(Y)))) {
// Peek through ptrtoints
match(X, m_PtrToIntSameSize(DL, m_Value(X)));
match(Y, m_PtrToIntSameSize(DL, m_Value(Y)));
if ((X == LHS && Y == RHS) || (X == RHS && Y == LHS)) {
Constant *NullVal = Constant::getNullValue(Val->getType());
if (EdgePred == ICmpInst::ICMP_EQ)
return ValueLatticeElement::get(NullVal);
return ValueLatticeElement::getNot(NullVal);
}
}

return ValueLatticeElement::getOverdefined();
}

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168 changes: 168 additions & 0 deletions llvm/test/Transforms/CorrelatedValuePropagation/umax.ll
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@@ -0,0 +1,168 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt < %s -passes=correlated-propagation -S | FileCheck %s

target datalayout = "p:32:32"

define i32 @infer_range_from_dom_equality(i32 %x, i32 %y) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_equality(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: ret i32 1
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 [[SUB]]
;
entry:
%cond = icmp eq i32 %x, %y
%sub = sub i32 %x, %y
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}

define i32 @infer_range_from_dom_equality_commuted1(i32 %x, i32 %y) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_equality_commuted1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: ret i32 1
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 [[SUB]]
;
entry:
%cond = icmp eq i32 %x, %y
%sub = sub i32 %y, %x
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}

define i32 @infer_range_from_dom_equality_commuted2(i32 %x, i32 %y) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_equality_commuted2(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[Y]], [[X]]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: ret i32 1
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 [[SUB]]
;
entry:
%cond = icmp eq i32 %y, %x
%sub = sub i32 %x, %y
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}

define i32 @infer_range_from_dom_equality_ptrdiff(ptr %x, ptr %y) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_equality_ptrdiff(
; CHECK-SAME: ptr [[X:%.*]], ptr [[Y:%.*]]) {
; CHECK-NEXT: [[COND:%.*]] = icmp eq ptr [[X]], [[Y]]
; CHECK-NEXT: [[XI:%.*]] = ptrtoint ptr [[X]] to i32
; CHECK-NEXT: [[YI:%.*]] = ptrtoint ptr [[Y]] to i32
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[XI]], [[YI]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: ret i32 1
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: ret i32 [[SUB]]
;
%cond = icmp eq ptr %x, %y
%xi = ptrtoint ptr %x to i32
%yi = ptrtoint ptr %y to i32
%sub = sub i32 %xi, %yi
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}

; Negative tests

define i32 @infer_range_from_dom_slt(i32 %x, i32 %y) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_slt(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp slt i32 [[X]], [[Y]]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[MAX1:%.*]] = call i32 @llvm.umax.i32(i32 [[SUB]], i32 1)
; CHECK-NEXT: ret i32 [[MAX1]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: [[MAX2:%.*]] = call i32 @llvm.umax.i32(i32 [[SUB]], i32 1)
; CHECK-NEXT: ret i32 [[MAX2]]
;
entry:
%cond = icmp slt i32 %x, %y
%sub = sub i32 %x, %y
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}

define i32 @infer_range_from_dom_equality_not_match(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: define range(i32 1, 0) i32 @infer_range_from_dom_equality_not_match(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]], i32 [[Z:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32 [[X]], [[Z]]
; CHECK-NEXT: [[SUB:%.*]] = sub i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
; CHECK: [[IF_THEN]]:
; CHECK-NEXT: [[MAX1:%.*]] = call i32 @llvm.umax.i32(i32 [[SUB]], i32 1)
; CHECK-NEXT: ret i32 [[MAX1]]
; CHECK: [[IF_ELSE]]:
; CHECK-NEXT: [[MAX2:%.*]] = call i32 @llvm.umax.i32(i32 [[SUB]], i32 1)
; CHECK-NEXT: ret i32 [[MAX2]]
;
entry:
%cond = icmp eq i32 %x, %z
%sub = sub i32 %x, %y
br i1 %cond, label %if.then, label %if.else

if.then:
%max1 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max1

if.else:
%max2 = call i32 @llvm.umax.i32(i32 %sub, i32 1)
ret i32 %max2
}
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