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[DebugInfo][LSR] Avoid crashes on large integer inputs

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SCEV-based salvaging in LSR translates SCEVs to DIExpressions. SCEVs may
contain very large integers but the translation does not support
integers greater than 64 bits. This patch adds checks to ensure
conversions of these large integers is not attempted. A regression test
is added to ensure no such translation is attempted.

Reviewed by: StephenTozer

PR: https://bugs.llvm.org/show_bug.cgi?id=51329

Differential Revision: https://reviews.llvm.org/D107438

(cherry picked from commit 21ee38e24f9801a567306b2a88defacf6e589a8b)
This commit is contained in:
Chris Jackson 2021-08-04 10:37:03 +01:00
parent 46ad88f625
commit 910de616a4
2 changed files with 57 additions and 2 deletions
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9
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -5906,9 +5906,12 @@ struct SCEVDbgValueBuilder {
pushValue(V);
}
void pushConst(const SCEVConstant *C) {
bool pushConst(const SCEVConstant *C) {
if (C->getAPInt().getMinSignedBits() > 64)
return false;
Expr.push_back(llvm::dwarf::DW_OP_consts);
Expr.push_back(C->getAPInt().getSExtValue());
return true;
}
/// Several SCEV types are sequences of the same arithmetic operator applied
@ -5947,7 +5950,7 @@ struct SCEVDbgValueBuilder {
bool pushSCEV(const llvm::SCEV *S) {
bool Success = true;
if (const SCEVConstant *StartInt = dyn_cast<SCEVConstant>(S)) {
pushConst(StartInt);
Success &= pushConst(StartInt);
} else if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(S)) {
if (!U->getValue())
@ -6033,6 +6036,8 @@ struct SCEVDbgValueBuilder {
/// SCEV constant value is an identity function.
bool isIdentityFunction(uint64_t Op, const SCEV *S) {
if (const SCEVConstant *C = dyn_cast<SCEVConstant>(S)) {
if (C->getAPInt().getMinSignedBits() > 64)
return false;
int64_t I = C->getAPInt().getSExtValue();
switch (Op) {
case llvm::dwarf::DW_OP_plus:

50
test/Transforms/LoopStrengthReduce/pr51329.ll Normal file
View File

@ -0,0 +1,50 @@
; RUN: opt -S -loop-reduce %s | FileCheck %s
;
; Test that LSR SCEV-based salvaging does not crash when translating SCEVs
; that contain integers with binary representations greater than 64-bits.
;
; CHECK: call void @llvm.dbg.value(metadata i64 %var2, metadata !{{[0-9]+}}, metadata !DIExpression(DW_OP_plus_uconst, 228, DW_OP_stack_value))
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
declare void @llvm.dbg.value(metadata, metadata, metadata)
; Function Attrs: nounwind
define hidden void @reproducer() local_unnamed_addr !dbg !5 {
init:
%0 = lshr i128 undef, 64
%var1 = trunc i128 %0 to i64
%1 = add nuw i64 undef, %var1
%var2 = lshr i64 %1, 12
br label %Label_d0
Label_d0: ; preds = %Label_d0, %init
%var3 = phi i64 [ %var2, %init ], [ %var4, %Label_d0 ]
call void @llvm.dbg.value(metadata i64 %var2, metadata !11, metadata !DIExpression(DW_OP_plus_uconst, 228, DW_OP_stack_value)), !dbg !12
%var4 = add i64 %var3, -1
%var5 = icmp eq i64 %var4, 0
br i1 %var5, label %Label_1bc, label %Label_d0
Label_1bc: ; preds = %Label_d0
ret void
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "frontend", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
!1 = !DIFile(filename: "source", directory: "")
!2 = !{}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{i32 1, !"wchar_size", i32 4}
!5 = distinct !DISubprogram(name: "reproducer", scope: !1, file: !1, line: 904320, type: !6, scopeLine: 904320, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !10)
!6 = !DISubroutineType(types: !7)
!7 = !{null, !8, !9, !9, !9, !9, !9, !9}
!8 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
!9 = !DIBasicType(name: "my_type", size: 64, encoding: DW_ATE_unsigned)
!10 = !{!11}
!11 = !DILocalVariable(name: "my_var", arg: 1, scope: !5, file: !1, line: 904320, type: !8)
!12 = !DILocation(line: 904544, scope: !5)