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andjo403andjo403
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[IPSCCP] Add range attribute handling (#86747)
Support the new range attribute to infer ConstantRanges in IPSCCP.
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4 files changed

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-4
lines changed

4 files changed

+197
-4
lines changed

‎llvm/include/llvm/Transforms/Utils/SCCPSolver.h

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -151,6 +151,10 @@ class SCCPSolver {
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/// works with both scalars and structs.
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void markOverdefined(Value *V);
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/// trackValueOfArgument - Mark the specified argument overdefined unless it
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/// have range attribute. This works with both scalars and structs.
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void trackValueOfArgument(Argument *V);
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// isStructLatticeConstant - Return true if all the lattice values
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// corresponding to elements of the structure are constants,
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// false otherwise.

‎llvm/lib/Transforms/IPO/SCCP.cpp

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -144,9 +144,8 @@ static bool runIPSCCP(
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// Assume the function is called.
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Solver.markBlockExecutable(&F.front());
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147-
// Assume nothing about the incoming arguments.
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for (Argument &AI : F.args())
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Solver.markOverdefined(&AI);
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Solver.trackValueOfArgument(&AI);
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}
151150

152151
// Determine if we can track any of the module's global variables. If so, add

‎llvm/lib/Transforms/Utils/SCCPSolver.cpp

Lines changed: 38 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -428,6 +428,13 @@ class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
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return markConstant(ValueState[V], V, C);
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}
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/// markConstantRange - Mark the object as constant range with \p CR. If the
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/// object is not a constant range with the range \p CR, add it to the
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/// instruction work list so that the users of the instruction are updated
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/// later.
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bool markConstantRange(ValueLatticeElement &IV, Value *V,
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const ConstantRange &CR);
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// markOverdefined - Make a value be marked as "overdefined". If the
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// value is not already overdefined, add it to the overdefined instruction
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// work list so that the users of the instruction are updated later.
@@ -788,6 +795,17 @@ class SCCPInstVisitor : public InstVisitor<SCCPInstVisitor> {
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markOverdefined(ValueState[V], V);
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}
790797

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void trackValueOfArgument(Argument *A) {
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if (A->getType()->isIntegerTy()) {
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if (std::optional<ConstantRange> Range = A->getRange()) {
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markConstantRange(ValueState[A], A, *Range);
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return;
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}
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}
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// Assume nothing about the incoming arguments without range.
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markOverdefined(A);
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}
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791809
bool isStructLatticeConstant(Function *F, StructType *STy);
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793811
Constant *getConstant(const ValueLatticeElement &LV, Type *Ty) const;
@@ -873,6 +891,15 @@ bool SCCPInstVisitor::markConstant(ValueLatticeElement &IV, Value *V,
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return true;
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}
875893

894+
bool SCCPInstVisitor::markConstantRange(ValueLatticeElement &IV, Value *V,
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const ConstantRange &CR) {
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if (!IV.markConstantRange(CR))
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return false;
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LLVM_DEBUG(dbgs() << "markConstantRange: " << CR << ": " << *V << '\n');
899+
pushToWorkList(IV, V);
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return true;
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}
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876903
bool SCCPInstVisitor::markOverdefined(ValueLatticeElement &IV, Value *V) {
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if (!IV.markOverdefined())
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return false;
@@ -1581,10 +1608,15 @@ void SCCPInstVisitor::visitStoreInst(StoreInst &SI) {
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}
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static ValueLatticeElement getValueFromMetadata(const Instruction *I) {
1584-
if (MDNode *Ranges = I->getMetadata(LLVMContext::MD_range))
1585-
if (I->getType()->isIntegerTy())
1611+
if (I->getType()->isIntegerTy()) {
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if (MDNode *Ranges = I->getMetadata(LLVMContext::MD_range))
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return ValueLatticeElement::getRange(
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getConstantRangeFromMetadata(*Ranges));
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if (const auto *CB = dyn_cast<CallBase>(I))
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if (std::optional<ConstantRange> Range = CB->getRange())
1618+
return ValueLatticeElement::getRange(*Range);
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}
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if (I->hasMetadata(LLVMContext::MD_nonnull))
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return ValueLatticeElement::getNot(
15901622
ConstantPointerNull::get(cast<PointerType>(I->getType())));
@@ -2090,6 +2122,10 @@ const SmallPtrSet<Function *, 16> SCCPSolver::getMRVFunctionsTracked() {
20902122

20912123
void SCCPSolver::markOverdefined(Value *V) { Visitor->markOverdefined(V); }
20922124

2125+
void SCCPSolver::trackValueOfArgument(Argument *V) {
2126+
Visitor->trackValueOfArgument(V);
2127+
}
2128+
20932129
bool SCCPSolver::isStructLatticeConstant(Function *F, StructType *STy) {
20942130
return Visitor->isStructLatticeConstant(F, STy);
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}

‎llvm/test/Transforms/SCCP/range-attribute.ll

Lines changed: 154 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,154 @@
1+
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2+
; RUN: opt < %s -passes=ipsccp -S | FileCheck %s
3+
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declare void @use(i1)
5+
declare i32 @get_i32()
6+
7+
define void @range_attribute(i32 range(i32 0, 10) %v) {
8+
; CHECK-LABEL: @range_attribute(
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; CHECK-NEXT: call void @use(i1 true)
10+
; CHECK-NEXT: [[C2:%.*]] = icmp ult i32 [[V:%.*]], 9
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; CHECK-NEXT: call void @use(i1 [[C2]])
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; CHECK-NEXT: call void @use(i1 false)
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; CHECK-NEXT: [[C4:%.*]] = icmp ugt i32 [[V]], 8
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; CHECK-NEXT: call void @use(i1 [[C4]])
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; CHECK-NEXT: ret void
16+
;
17+
%c1 = icmp ult i32 %v, 10
18+
call void @use(i1 %c1)
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%c2 = icmp ult i32 %v, 9
20+
call void @use(i1 %c2)
21+
%c3 = icmp ugt i32 %v, 9
22+
call void @use(i1 %c3)
23+
%c4 = icmp ugt i32 %v, 8
24+
call void @use(i1 %c4)
25+
ret void
26+
}
27+
28+
define i32 @range_attribute_single(i32 range(i32 0, 1) %v) {
29+
; CHECK-LABEL: @range_attribute_single(
30+
; CHECK-NEXT: ret i32 0
31+
;
32+
ret i32 %v
33+
}
34+
35+
define void @call_range_attribute() {
36+
; CHECK-LABEL: @call_range_attribute(
37+
; CHECK-NEXT: [[V:%.*]] = call range(i32 0, 10) i32 @get_i32()
38+
; CHECK-NEXT: call void @use(i1 true)
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; CHECK-NEXT: [[C2:%.*]] = icmp ult i32 [[V]], 9
40+
; CHECK-NEXT: call void @use(i1 [[C2]])
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; CHECK-NEXT: call void @use(i1 false)
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; CHECK-NEXT: [[C4:%.*]] = icmp ugt i32 [[V]], 8
43+
; CHECK-NEXT: call void @use(i1 [[C4]])
44+
; CHECK-NEXT: ret void
45+
;
46+
%v = call range(i32 0, 10) i32 @get_i32()
47+
%c1 = icmp ult i32 %v, 10
48+
call void @use(i1 %c1)
49+
%c2 = icmp ult i32 %v, 9
50+
call void @use(i1 %c2)
51+
%c3 = icmp ugt i32 %v, 9
52+
call void @use(i1 %c3)
53+
%c4 = icmp ugt i32 %v, 8
54+
call void @use(i1 %c4)
55+
ret void
56+
}
57+
58+
59+
declare range(i32 0, 10) i32 @get_i32_in_range()
60+
61+
define void @call_range_result() {
62+
; CHECK-LABEL: @call_range_result(
63+
; CHECK-NEXT: [[V:%.*]] = call i32 @get_i32_in_range()
64+
; CHECK-NEXT: call void @use(i1 true)
65+
; CHECK-NEXT: [[C2:%.*]] = icmp ult i32 [[V]], 9
66+
; CHECK-NEXT: call void @use(i1 [[C2]])
67+
; CHECK-NEXT: call void @use(i1 false)
68+
; CHECK-NEXT: [[C4:%.*]] = icmp ugt i32 [[V]], 8
69+
; CHECK-NEXT: call void @use(i1 [[C4]])
70+
; CHECK-NEXT: ret void
71+
;
72+
%v = call i32 @get_i32_in_range()
73+
%c1 = icmp ult i32 %v, 10
74+
call void @use(i1 %c1)
75+
%c2 = icmp ult i32 %v, 9
76+
call void @use(i1 %c2)
77+
%c3 = icmp ugt i32 %v, 9
78+
call void @use(i1 %c3)
79+
%c4 = icmp ugt i32 %v, 8
80+
call void @use(i1 %c4)
81+
ret void
82+
}
83+
84+
define internal i1 @ip_cmp_range_attribute(i32 %v) {
85+
; CHECK-LABEL: @ip_cmp_range_attribute(
86+
; CHECK-NEXT: ret i1 undef
87+
;
88+
%c = icmp ult i32 %v, 10
89+
ret i1 %c
90+
}
91+
92+
define i1 @ip_range_attribute(i32 range(i32 0, 10) %v) {
93+
; CHECK-LABEL: @ip_range_attribute(
94+
; CHECK-NEXT: [[C:%.*]] = call i1 @ip_cmp_range_attribute(i32 [[V:%.*]])
95+
; CHECK-NEXT: ret i1 true
96+
;
97+
%c = call i1 @ip_cmp_range_attribute(i32 %v)
98+
ret i1 %c
99+
}
100+
101+
define internal i1 @ip_cmp_range_call(i32 %v) {
102+
; CHECK-LABEL: @ip_cmp_range_call(
103+
; CHECK-NEXT: ret i1 undef
104+
;
105+
%c = icmp ult i32 %v, 10
106+
ret i1 %c
107+
}
108+
109+
define i1 @ip_range_call() {
110+
; CHECK-LABEL: @ip_range_call(
111+
; CHECK-NEXT: [[V:%.*]] = call range(i32 0, 10) i32 @get_i32()
112+
; CHECK-NEXT: [[C:%.*]] = call i1 @ip_cmp_range_call(i32 [[V]])
113+
; CHECK-NEXT: ret i1 true
114+
;
115+
%v = call range(i32 0, 10) i32 @get_i32()
116+
%c = call i1 @ip_cmp_range_call(i32 %v)
117+
ret i1 %c
118+
}
119+
120+
define internal i1 @ip_cmp_range_result(i32 %v) {
121+
; CHECK-LABEL: @ip_cmp_range_result(
122+
; CHECK-NEXT: ret i1 undef
123+
;
124+
%c = icmp ult i32 %v, 10
125+
ret i1 %c
126+
}
127+
128+
define i1 @ip_range_result() {
129+
; CHECK-LABEL: @ip_range_result(
130+
; CHECK-NEXT: [[V:%.*]] = call range(i32 0, 10) i32 @get_i32()
131+
; CHECK-NEXT: [[C:%.*]] = call i1 @ip_cmp_range_result(i32 [[V]])
132+
; CHECK-NEXT: ret i1 true
133+
;
134+
%v = call range(i32 0, 10) i32 @get_i32()
135+
%c = call i1 @ip_cmp_range_result(i32 %v)
136+
ret i1 %c
137+
}
138+
139+
define internal i1 @ip_cmp_with_range_attribute(i32 range(i32 0, 10) %v) {
140+
; CHECK-LABEL: @ip_cmp_with_range_attribute(
141+
; CHECK-NEXT: ret i1 undef
142+
;
143+
%c = icmp eq i32 %v, 5
144+
ret i1 %c
145+
}
146+
147+
define i1 @ip_range_attribute_constant() {
148+
; CHECK-LABEL: @ip_range_attribute_constant(
149+
; CHECK-NEXT: [[C:%.*]] = call i1 @ip_cmp_with_range_attribute(i32 5)
150+
; CHECK-NEXT: ret i1 true
151+
;
152+
%c = call i1 @ip_cmp_with_range_attribute(i32 5)
153+
ret i1 %c
154+
}

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