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[offload] Remove redundant checks in MappingInfoTy::lookupMapping #127638

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Merged
kparzysz merged 2 commits into from
Feb 18, 2025
Merged

[offload] Remove redundant checks in MappingInfoTy::lookupMapping #127638

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[offload] Remove redundant checks in MappingInfoTy::lookupMapping
kparzysz Feb 17, 2025
1015800
use OpenMP spec terminology in comments
kparzysz Feb 18, 2025
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37 changes: 17 additions & 20 deletions offload/libomptarget/OpenMP/Mapping.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -141,48 +141,45 @@ LookupResult MappingInfoTy::lookupMapping(HDTTMapAccessorTy &HDTTMap,
if (HDTTMap->empty())
return LR;

// HDTTMap is std::set, ordered by HstPtrBegin.
// Upper is the first element whose HstPtrBegin > HP.
auto Upper = HDTTMap->upper_bound(HP);

if (Size == 0) {
// specification v5.1 Pointer Initialization for Device Data Environments
// upper_bound satisfies
// std::prev(upper)->HDTT.HstPtrBegin <= hp < upper->HDTT.HstPtrBegin
// HP satisfies
// std::prev(Upper)->HDTT.HstPtrBegin <= HP < Upper->HDTT.HstPtrBegin
if (Upper != HDTTMap->begin()) {
LR.TPR.setEntry(std::prev(Upper)->HDTT, OwnedTPR);
// the left side of extended address range is satisfied.
// hp >= LR.TPR.getEntry()->HstPtrBegin || hp >=
// LR.TPR.getEntry()->HstPtrBase
LR.Flags.IsContained = HP < LR.TPR.getEntry()->HstPtrEnd ||
HP < LR.TPR.getEntry()->HstPtrBase;
// We know that HP >= LR.TPR.getEntry()->HstPtrBegin
LR.Flags.IsContained = HP < LR.TPR.getEntry()->HstPtrEnd;
}

if (!LR.Flags.IsContained && Upper != HDTTMap->end()) {
LR.TPR.setEntry(Upper->HDTT, OwnedTPR);
// the right side of extended address range is satisfied.
// hp < LR.TPR.getEntry()->HstPtrEnd || hp < LR.TPR.getEntry()->HstPtrBase
// This is a special case: HP is not really contained in the mapped
// address range, but it's contained in the extended address range,
// which suffices to get the mapping of the base pointer.
// We know that HP < LR.TPR.getEntry()->HstPtrBegin
LR.Flags.IsContained = HP >= LR.TPR.getEntry()->HstPtrBase;
}
} else {
// check the left bin
if (Upper != HDTTMap->begin()) {
LR.TPR.setEntry(std::prev(Upper)->HDTT, OwnedTPR);
// Is it contained?
LR.Flags.IsContained = HP >= LR.TPR.getEntry()->HstPtrBegin &&
HP < LR.TPR.getEntry()->HstPtrEnd &&
// We know that HP >= LR.TPR.getEntry()->HstPtrBegin
LR.Flags.IsContained = HP < LR.TPR.getEntry()->HstPtrEnd &&
(HP + Size) <= LR.TPR.getEntry()->HstPtrEnd;
// Does it extend beyond the mapped region?
// Does it extend beyond the mapped address range?
LR.Flags.ExtendsAfter = HP < LR.TPR.getEntry()->HstPtrEnd &&
(HP + Size) > LR.TPR.getEntry()->HstPtrEnd;
}

// check the right bin
if (!(LR.Flags.IsContained || LR.Flags.ExtendsAfter) &&
Upper != HDTTMap->end()) {
LR.TPR.setEntry(Upper->HDTT, OwnedTPR);
// Does it extend into an already mapped region?
LR.Flags.ExtendsBefore = HP < LR.TPR.getEntry()->HstPtrBegin &&
(HP + Size) > LR.TPR.getEntry()->HstPtrBegin;
// Does it extend beyond the mapped region?
// Does it extend into an already mapped address range?
// We know that HP < LR.TPR.getEntry()->HstPtrBegin
LR.Flags.ExtendsBefore = (HP + Size) > LR.TPR.getEntry()->HstPtrBegin;
// Does it extend beyond the mapped address range?
LR.Flags.ExtendsAfter = HP < LR.TPR.getEntry()->HstPtrEnd &&
(HP + Size) > LR.TPR.getEntry()->HstPtrEnd;
}
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