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arsenmarsenm
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llvm-reduce: Try to preserve instruction metadata as argument attributes (#133557)
Fixes #131825
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‎llvm/include/llvm/IR/Attributes.h

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -42,6 +42,7 @@ class ConstantRangeList;
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class FoldingSetNodeID;
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class Function;
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class LLVMContext;
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class Instruction;
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class Type;
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class raw_ostream;
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enum FPClassTest : unsigned;
@@ -1285,6 +1286,11 @@ class AttrBuilder {
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/// Add initializes attribute.
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AttrBuilder &addInitializesAttr(const ConstantRangeList &CRL);
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/// Add 0 or more parameter attributes which are equivalent to metadata
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/// attached to \p I. e.g. !align -> align. This assumes the argument type is
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/// the same as the original instruction and the attribute is compatible.
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AttrBuilder &addFromEquivalentMetadata(const Instruction &I);
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ArrayRef<Attribute> attrs() const { return Attrs; }
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12901296
bool operator==(const AttrBuilder &B) const;

‎llvm/lib/IR/Attributes.cpp

Lines changed: 32 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2291,6 +2291,38 @@ AttrBuilder &AttrBuilder::addInitializesAttr(const ConstantRangeList &CRL) {
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return addConstantRangeListAttr(Attribute::Initializes, CRL.rangesRef());
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}
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2294+
AttrBuilder &AttrBuilder::addFromEquivalentMetadata(const Instruction &I) {
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if (const MDNode *NonNull = I.getMetadata(LLVMContext::MD_nonnull))
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addAttribute(Attribute::NonNull);
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if (const MDNode *NoUndef = I.getMetadata(LLVMContext::MD_noundef))
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addAttribute(Attribute::NoUndef);
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if (const MDNode *Align = I.getMetadata(LLVMContext::MD_align)) {
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ConstantInt *CI = mdconst::extract<ConstantInt>(Align->getOperand(0));
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addAlignmentAttr(CI->getZExtValue());
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}
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if (const MDNode *Dereferenceable =
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I.getMetadata(LLVMContext::MD_dereferenceable)) {
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ConstantInt *CI =
2309+
mdconst::extract<ConstantInt>(Dereferenceable->getOperand(0));
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addDereferenceableAttr(CI->getZExtValue());
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}
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if (const MDNode *DereferenceableOrNull =
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I.getMetadata(LLVMContext::MD_dereferenceable_or_null)) {
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ConstantInt *CI =
2316+
mdconst::extract<ConstantInt>(DereferenceableOrNull->getOperand(0));
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addDereferenceableAttr(CI->getZExtValue());
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}
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if (const MDNode *Range = I.getMetadata(LLVMContext::MD_range))
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addRangeAttr(getConstantRangeFromMetadata(*Range));
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return *this;
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}
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AttrBuilder &AttrBuilder::merge(const AttrBuilder &B) {
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// TODO: Could make this O(n) as we're merging two sorted lists.
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for (const auto &I : B.attrs())

‎llvm/test/tools/llvm-reduce/reduce-operands-to-args-metadata-to-attributes.ll

Lines changed: 77 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,77 @@
1+
; Check that equivalent parameter attributes are introduced when
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; moving instructions with metadata to arguments.
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; RUN: llvm-reduce %s -o %t --abort-on-invalid-reduction --delta-passes=operands-to-args --test FileCheck --test-arg %s --test-arg --check-prefix=INTERESTING --test-arg --input-file
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; RUN: FileCheck --input-file %t --check-prefix=REDUCED %s
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; INTERESTING-LABEL: define ptr @use_nonnull(
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; REDUCED-LABEL: define ptr @use_nonnull(ptr nonnull %nonnull) {
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define ptr @use_nonnull() {
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%nonnull = load ptr, ptr null, !nonnull !0
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ret ptr %nonnull
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}
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; INTERESTING-LABEL: define void @use_noundef(
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; REDUCED-LABEL: define void @use_noundef(ptr noundef %noundef, <2 x ptr> noundef %noundef_vec) {
16+
define void @use_noundef() {
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%noundef = load ptr, ptr null, !noundef !0
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%noundef_vec = load <2 x ptr>, ptr null, !noundef !0
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store ptr %noundef, ptr null
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store <2 x ptr> %noundef_vec, ptr null
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ret void
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}
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; INTERESTING-LABEL: define ptr @use_align(
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; REDUCED-LABEL: define ptr @use_align(ptr align 16 %align) {
26+
define ptr @use_align() {
27+
%align = load ptr, ptr null, !align !1
28+
ret ptr %align
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}
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31+
; INTERESTING-LABEL: define ptr @use_dereferenceable(
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; REDUCED-LABEL: define ptr @use_dereferenceable(ptr dereferenceable(12345) %deref) {
33+
define ptr @use_dereferenceable() {
34+
%deref = load ptr, ptr null, !dereferenceable !2
35+
ret ptr %deref
36+
}
37+
38+
; INTERESTING-LABEL: define ptr @use_dereferenceable_or_null(
39+
; REDUCED-LABEL: define ptr @use_dereferenceable_or_null(ptr dereferenceable(77777) %deref) {
40+
define ptr @use_dereferenceable_or_null() {
41+
%deref = load ptr, ptr null, !dereferenceable_or_null !3
42+
ret ptr %deref
43+
}
44+
45+
; INTERESTING-LABEL: define void @use_range(
46+
; REDUCED-LABEL: define void @use_range(i32 range(i32 8, 25) %simple_range, i32 range(i32 8, 420) %disjoint_range, i32 range(i32 42, 0) %wrapping_range, <2 x i32> range(i32 8, 25) %vector_range) {
47+
define void @use_range() {
48+
%simple_range = load i32, ptr null, !range !4
49+
%disjoint_range = load i32, ptr null, !range !5
50+
%wrapping_range = load i32, ptr null, !range !6
51+
%vector_range = load <2 x i32>, ptr null, !range !4
52+
store i32 %simple_range, ptr null
53+
store i32 %disjoint_range, ptr null
54+
store i32 %wrapping_range, ptr null
55+
store <2 x i32> %vector_range, ptr null
56+
ret void
57+
}
58+
59+
; INTERESTING-LABEL: define void @use_noundef_range(
60+
; REDUCED-LABEL: define void @use_noundef_range(i32 noundef range(i32 8, 25) %load, <2 x i32> noundef range(i32 8, 25) %load_vec) {
61+
define void @use_noundef_range() {
62+
%load = load i32, ptr null, !range !4, !noundef !0
63+
%load_vec = load <2 x i32>, ptr null, !range !4, !noundef !0
64+
store i32 %load, ptr null
65+
store <2 x i32> %load_vec, ptr null
66+
ret void
67+
}
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69+
70+
71+
!0 = !{}
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!1 = !{i64 16}
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!2 = !{i64 12345}
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!3 = !{i64 77777}
75+
!4 = !{i32 8, i32 25}
76+
!5 = !{i32 8, i32 25, i32 69, i32 420}
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!6 = !{i32 42, i32 0}

‎llvm/tools/llvm-reduce/deltas/ReduceOperandsToArgs.cpp

Lines changed: 10 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -159,6 +159,8 @@ static void substituteOperandWithArgument(Function *OldF,
159159
VMap[&OldArg] = &NewArg; // Add mapping to VMap
160160
}
161161

162+
LLVMContext &Ctx = OldF->getContext();
163+
162164
// Adjust the new parameters.
163165
ValueToValueMapTy OldValMap;
164166
for (auto Z : zip_first(UniqueValues, drop_begin(NewF->args(), ArgOffset))) {
@@ -175,9 +177,16 @@ static void substituteOperandWithArgument(Function *OldF,
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176178
// Replace the actual operands.
177179
for (Use *Op : OpsToReplace) {
178-
Value *NewArg = OldValMap.lookup(Op->get());
180+
Argument *NewArg = cast<Argument>(OldValMap.lookup(Op->get()));
179181
auto *NewUser = cast<Instruction>(VMap.lookup(Op->getUser()));
180182

183+
// Try to preserve any information contained metadata annotations as the
184+
// equivalent parameter attributes if possible.
185+
if (auto *MDSrcInst = dyn_cast<Instruction>(Op)) {
186+
AttrBuilder AB(Ctx);
187+
NewArg->addAttrs(AB.addFromEquivalentMetadata(*MDSrcInst));
188+
}
189+
181190
if (PHINode *NewPhi = dyn_cast<PHINode>(NewUser)) {
182191
PHINode *OldPhi = cast<PHINode>(Op->getUser());
183192
BasicBlock *OldBB = OldPhi->getIncomingBlock(*Op);

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