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TempRValueOpt: fix a wrong assert. #60902

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Merged
merged 1 commit into from
Sep 1, 2022
Merged

TempRValueOpt: fix a wrong assert. #60902

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13 changes: 9 additions & 4 deletions lib/SILOptimizer/Transforms/TempRValueElimination.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -400,10 +400,15 @@ bool TempRValueOptPass::extendAccessScopes(
if (endAccessToMove)
return false;
// Is this the end of an access scope of the copy-source?
if (!aa->isNoAlias(copySrc, endAccess->getSource())) {
assert(endAccess->getBeginAccess()->getAccessKind() ==
SILAccessKind::Read &&
"a may-write end_access should not be in the copysrc lifetime");
if (!aa->isNoAlias(copySrc, endAccess->getSource()) &&

// There cannot be any aliasing modifying accesses within the liferange
// of the temporary, because we would have cought this in
// `getLastUseWhileSourceIsNotModified`.
// But there are cases where `AliasAnalysis::isNoAlias` is less precise
// than `AliasAnalysis::mayWriteToMemory`. Therefore, just ignore any
// non-read accesses.
endAccess->getBeginAccess()->getAccessKind() == SILAccessKind::Read) {

// Don't move instructions beyond the block's terminator.
if (isa<TermInst>(lastUseInst))
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20 changes: 20 additions & 0 deletions test/SILOptimizer/temp_rvalue_opt.sil
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Expand Up @@ -739,3 +739,23 @@ bb0(%0 : $*Klass):
%9999 = tuple()
return %9999 : $()
}

// CHECK-LABEL: sil @test_aliasing_modify_access
// CHECK: [[A:%.*]] = ref_element_addr [immutable] %0 : $Klass, #Klass.a
// CHECK-NOT: copy_addr
// CHECK: [[L:%.*]] = load [[A]]
// CHECK: return [[L]]
// CHECK: } // end sil function 'test_aliasing_modify_access'
sil @test_aliasing_modify_access : $@convention(thin) (@guaranteed Klass, @guaranteed Klass) -> @owned String {
bb0(%0 : $Klass, %1 : $Klass):
%2 = ref_element_addr [immutable] %0 : $Klass, #Klass.a
%3 = alloc_stack $String
copy_addr %2 to [initialization] %3 : $*String
%4 = ref_element_addr %1 : $Klass, #Klass.a
%5 = begin_access [modify] [dynamic] [no_nested_conflict] %4 : $*String
end_access %5 : $*String
%323 = load %3 : $*String
destroy_addr %3 : $*String
dealloc_stack %3 : $*String
return %323 : $String
}