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[FunctionAttrs] Determine underlying object by getUnderlyingObjectAggressive #100102

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Merged
merged 3 commits into from
Jul 23, 2024
Merged

[FunctionAttrs] Determine underlying object by getUnderlyingObjectAggressive #100102

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781c2e6
Pre-commit test cases
dianqk Jul 23, 2024
9c73bbf
[FunctionAttrs] Determine underlying object by `getUnderlyingObjectAg…
dianqk Jul 23, 2024
1156527
Add FIXME for future optimization
dianqk Jul 23, 2024
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2 changes: 1 addition & 1 deletion llvm/lib/Transforms/IPO/FunctionAttrs.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,7 @@ static void addLocAccess(MemoryEffects &ME, const MemoryLocation &Loc,
if (isNoModRef(MR))
return;

const Value *UO = getUnderlyingObject(Loc.Ptr);
const Value *UO = getUnderlyingObjectAggressive(Loc.Ptr);
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Compile-time impact: http://llvm-compile-time-tracker.com/compare.php?from=c1b70fa5bfea973d4141e27cf9668e9325609e19&to=9c73bbf882a265931e4669e6da2a1c99acbb4efe&stat=instructions:u

assert(!isa<AllocaInst>(UO) &&
"Should have been handled by getModRefInfoMask()");
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Should convert this into if(isa<AllocaInst>(UO)) return.

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Thanks! I see it in the logs now. It doesn't seem to require additional test cases, so I will submit it directly later.

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Reland with a test case: 559be8e.

if (isa<Argument>(UO)) {
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124 changes: 124 additions & 0 deletions llvm/test/Transforms/FunctionAttrs/argmemonly.ll
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Expand Up @@ -489,3 +489,127 @@ define void @test_scc_argmem_read_2(ptr %p) {
call void @test_scc_argmem_read_1(ptr %p)
ret void
}

define i64 @select_same_obj(i1 %c, ptr %p, i64 %x) {
; FNATTRS: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read)
; FNATTRS-LABEL: define i64 @select_same_obj
; FNATTRS-SAME: (i1 [[C:%.*]], ptr nocapture readonly [[P:%.*]], i64 [[X:%.*]]) #[[ATTR1]] {
; FNATTRS-NEXT: entry:
; FNATTRS-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[P]], i64 [[X]]
; FNATTRS-NEXT: [[P3:%.*]] = select i1 [[C]], ptr [[P]], ptr [[P2]]
; FNATTRS-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; FNATTRS-NEXT: ret i64 [[R]]
;
; ATTRIBUTOR: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
; ATTRIBUTOR-LABEL: define i64 @select_same_obj
; ATTRIBUTOR-SAME: (i1 [[C:%.*]], ptr nocapture nofree readonly [[P:%.*]], i64 [[X:%.*]]) #[[ATTR0]] {
; ATTRIBUTOR-NEXT: entry:
; ATTRIBUTOR-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[P]], i64 [[X]]
; ATTRIBUTOR-NEXT: [[P3:%.*]] = select i1 [[C]], ptr [[P]], ptr [[P2]]
; ATTRIBUTOR-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; ATTRIBUTOR-NEXT: ret i64 [[R]]
;
entry:
%p2 = getelementptr i8, ptr %p, i64 %x
%p3 = select i1 %c, ptr %p, ptr %p2
%r = load i64, ptr %p3
ret i64 %r
}

; FIXME: This could be `memory(argmem: read)`.
define i64 @select_different_obj(i1 %c, ptr %p, ptr %p2) {
; FNATTRS: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none)
; FNATTRS-LABEL: define i64 @select_different_obj
; FNATTRS-SAME: (i1 [[C:%.*]], ptr nocapture readonly [[P:%.*]], ptr nocapture readonly [[P2:%.*]]) #[[ATTR3]] {
; FNATTRS-NEXT: entry:
; FNATTRS-NEXT: [[P3:%.*]] = select i1 [[C]], ptr [[P]], ptr [[P2]]
; FNATTRS-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; FNATTRS-NEXT: ret i64 [[R]]
;
; ATTRIBUTOR: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
; ATTRIBUTOR-LABEL: define i64 @select_different_obj
; ATTRIBUTOR-SAME: (i1 [[C:%.*]], ptr nocapture nofree readonly [[P:%.*]], ptr nocapture nofree readonly [[P2:%.*]]) #[[ATTR0]] {
; ATTRIBUTOR-NEXT: entry:
; ATTRIBUTOR-NEXT: [[P3:%.*]] = select i1 [[C]], ptr [[P]], ptr [[P2]]
; ATTRIBUTOR-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; ATTRIBUTOR-NEXT: ret i64 [[R]]
;
entry:
%p3 = select i1 %c, ptr %p, ptr %p2
%r = load i64, ptr %p3
ret i64 %r
}

define i64 @phi_same_obj(i1 %c, ptr %p, i64 %x) {
; FNATTRS: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read)
; FNATTRS-LABEL: define i64 @phi_same_obj
; FNATTRS-SAME: (i1 [[C:%.*]], ptr nocapture readonly [[P:%.*]], i64 [[X:%.*]]) #[[ATTR1]] {
; FNATTRS-NEXT: entry:
; FNATTRS-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[P]], i64 [[X]]
; FNATTRS-NEXT: br i1 [[C]], label [[IF:%.*]], label [[JOIN:%.*]]
; FNATTRS: if:
; FNATTRS-NEXT: br label [[JOIN]]
; FNATTRS: join:
; FNATTRS-NEXT: [[P3:%.*]] = phi ptr [ [[P]], [[IF]] ], [ [[P2]], [[ENTRY:%.*]] ]
; FNATTRS-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; FNATTRS-NEXT: ret i64 [[R]]
;
; ATTRIBUTOR: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read)
; ATTRIBUTOR-LABEL: define i64 @phi_same_obj
; ATTRIBUTOR-SAME: (i1 [[C:%.*]], ptr nocapture nofree readonly [[P:%.*]], i64 [[X:%.*]]) #[[ATTR1]] {
; ATTRIBUTOR-NEXT: entry:
; ATTRIBUTOR-NEXT: [[P2:%.*]] = getelementptr i8, ptr [[P]], i64 [[X]]
; ATTRIBUTOR-NEXT: br i1 [[C]], label [[IF:%.*]], label [[JOIN:%.*]]
; ATTRIBUTOR: if:
; ATTRIBUTOR-NEXT: br label [[JOIN]]
; ATTRIBUTOR: join:
; ATTRIBUTOR-NEXT: [[P3:%.*]] = phi ptr [ [[P]], [[IF]] ], [ [[P2]], [[ENTRY:%.*]] ]
; ATTRIBUTOR-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; ATTRIBUTOR-NEXT: ret i64 [[R]]
;
entry:
%p2 = getelementptr i8, ptr %p, i64 %x
br i1 %c, label %if, label %join
if:
br label %join
join:
%p3 = phi ptr [ %p, %if ], [ %p2, %entry ]
%r = load i64, ptr %p3
ret i64 %r
}

; FIXME: This could be `memory(argmem: read)`.
define i64 @phi_different_obj(i1 %c, ptr %p, ptr %p2) {
; FNATTRS: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(read, inaccessiblemem: none)
; FNATTRS-LABEL: define i64 @phi_different_obj
; FNATTRS-SAME: (i1 [[C:%.*]], ptr nocapture readonly [[P:%.*]], ptr nocapture readonly [[P2:%.*]]) #[[ATTR3]] {
; FNATTRS-NEXT: entry:
; FNATTRS-NEXT: br i1 [[C]], label [[IF:%.*]], label [[JOIN:%.*]]
; FNATTRS: if:
; FNATTRS-NEXT: br label [[JOIN]]
; FNATTRS: join:
; FNATTRS-NEXT: [[P3:%.*]] = phi ptr [ [[P]], [[IF]] ], [ [[P2]], [[ENTRY:%.*]] ]
; FNATTRS-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; FNATTRS-NEXT: ret i64 [[R]]
;
; ATTRIBUTOR: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(argmem: read)
; ATTRIBUTOR-LABEL: define i64 @phi_different_obj
; ATTRIBUTOR-SAME: (i1 [[C:%.*]], ptr nocapture nofree readonly [[P:%.*]], ptr nocapture nofree readonly [[P2:%.*]]) #[[ATTR1]] {
; ATTRIBUTOR-NEXT: entry:
; ATTRIBUTOR-NEXT: br i1 [[C]], label [[IF:%.*]], label [[JOIN:%.*]]
; ATTRIBUTOR: if:
; ATTRIBUTOR-NEXT: br label [[JOIN]]
; ATTRIBUTOR: join:
; ATTRIBUTOR-NEXT: [[P3:%.*]] = phi ptr [ [[P]], [[IF]] ], [ [[P2]], [[ENTRY:%.*]] ]
; ATTRIBUTOR-NEXT: [[R:%.*]] = load i64, ptr [[P3]], align 4
; ATTRIBUTOR-NEXT: ret i64 [[R]]
;
entry:
br i1 %c, label %if, label %join
if:
br label %join
join:
%p3 = phi ptr [ %p, %if ], [ %p2, %entry ]
%r = load i64, ptr %p3
ret i64 %r
}
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