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[Attributor] Deal with complex PHI nodes better during AAPointerInfo 

We were quite conservative when it came to PHI node handling to avoid
recursive reasoning. Now we check more direct if we have seen a PHI
already or not. This allows non-recursive PHI chains to be handled.

This also exposed a bug as we did only model the effect of one loop
traversal. `phi_no_store_3` has been adapted to show how we would have
used `undef` instead of `1` before. With this patch we don't replace
it at all, which is expected as we do not argue about loop iterations
(or alignments).
This commit is contained in:
Johannes Doerfert 2022-07-10 13:49:36 -05:00
parent 142897dd7d
commit ad98ef8be4
2 changed files with 64 additions and 36 deletions
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29
llvm/lib/Transforms/IPO/AttributorAttributes.cpp
View File

@ -1310,6 +1310,7 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
if (isa<PHINode>(Usr)) {
// Note the order here, the Usr access might change the map, CurPtr is
// already in it though.
bool IsFirstPHIUser = !OffsetInfoMap.count(Usr);
OffsetInfo &UsrOI = OffsetInfoMap[Usr];
OffsetInfo &PtrOI = OffsetInfoMap[CurPtr];
// Check if the PHI is invariant (so far).
@ -1325,25 +1326,25 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
}
// Check if the PHI operand is not dependent on the PHI itself.
// TODO: This is not great as we look at the pointer type. However, it
// is unclear where the Offset size comes from with typeless pointers.
APInt Offset(
DL.getIndexSizeInBits(CurPtr->getType()->getPointerAddressSpace()),
0);
if (&AssociatedValue == CurPtr->stripAndAccumulateConstantOffsets(
DL, Offset, /* AllowNonInbounds */ true)) {
if (Offset != PtrOI.Offset) {
LLVM_DEBUG(dbgs()
<< "[AAPointerInfo] PHI operand pointer offset mismatch "
<< *CurPtr << " in " << *Usr << "\n");
return false;
}
return HandlePassthroughUser(Usr, PtrOI, Follow);
Value *CurPtrBase = CurPtr->stripAndAccumulateConstantOffsets(
DL, Offset, /* AllowNonInbounds */ true);
auto It = OffsetInfoMap.find(CurPtrBase);
if (It != OffsetInfoMap.end()) {
Offset += It->getSecond().Offset;
if (IsFirstPHIUser || Offset == UsrOI.Offset)
return HandlePassthroughUser(Usr, PtrOI, Follow);
LLVM_DEBUG(dbgs()
<< "[AAPointerInfo] PHI operand pointer offset mismatch "
<< *CurPtr << " in " << *Usr << "\n");
} else {
LLVM_DEBUG(dbgs() << "[AAPointerInfo] PHI operand is too complex "
<< *CurPtr << " in " << *Usr << "\n");
}
// TODO: Approximate in case we know the direction of the recurrence.
LLVM_DEBUG(dbgs() << "[AAPointerInfo] PHI operand is too complex "
<< *CurPtr << " in " << *Usr << "\n");
UsrOI = PtrOI;
UsrOI.Offset = OffsetAndSize::Unknown;
Follow = true;
@ -1381,7 +1382,7 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
Changed = translateAndAddState(A, CSArgPI,
OffsetInfoMap[CurPtr].Offset, *CB) |
Changed;
return true;
return isValidState();
}
LLVM_DEBUG(dbgs() << "[AAPointerInfo] Call user not handled " << *CB
<< "\n");

71
llvm/test/Transforms/Attributor/value-simplify-pointer-info.ll
View File

@ -3068,14 +3068,14 @@ define i8 @phi_no_store_2() {
; IS__TUNIT_OPM: loop:
; IS__TUNIT_OPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a2 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
; IS__TUNIT_OPM-NEXT: [[I:%.*]] = phi i8 [ 0, [[ENTRY]] ], [ [[O:%.*]], [[LOOP]] ]
; IS__TUNIT_OPM-NEXT: store i8 1, i8* [[P]], align 2
; IS__TUNIT_OPM-NEXT: [[G]] = getelementptr i8, i8* bitcast (i32* @a2 to i8*), i64 2
; IS__TUNIT_OPM-NEXT: [[O]] = add nsw i8 [[I]], 1
; IS__TUNIT_OPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__TUNIT_OPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__TUNIT_OPM: end:
; IS__TUNIT_OPM-NEXT: [[L21:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 2), align 2
; IS__TUNIT_OPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], 0
; IS__TUNIT_OPM-NEXT: [[L22:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 3), align 1
; IS__TUNIT_OPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], [[L22]]
; IS__TUNIT_OPM-NEXT: ret i8 [[ADD]]
;
; IS__TUNIT_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn
@ -3086,14 +3086,14 @@ define i8 @phi_no_store_2() {
; IS__TUNIT_NPM: loop:
; IS__TUNIT_NPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a2 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
; IS__TUNIT_NPM-NEXT: [[I:%.*]] = phi i8 [ 0, [[ENTRY]] ], [ [[O:%.*]], [[LOOP]] ]
; IS__TUNIT_NPM-NEXT: store i8 1, i8* [[P]], align 2
; IS__TUNIT_NPM-NEXT: [[G]] = getelementptr i8, i8* bitcast (i32* @a2 to i8*), i64 2
; IS__TUNIT_NPM-NEXT: [[O]] = add nsw i8 [[I]], 1
; IS__TUNIT_NPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__TUNIT_NPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__TUNIT_NPM: end:
; IS__TUNIT_NPM-NEXT: [[L21:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 2), align 2
; IS__TUNIT_NPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], 0
; IS__TUNIT_NPM-NEXT: [[L22:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 3), align 1
; IS__TUNIT_NPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], [[L22]]
; IS__TUNIT_NPM-NEXT: ret i8 [[ADD]]
;
; IS__CGSCC_OPM: Function Attrs: nofree norecurse nosync nounwind
@ -3104,14 +3104,14 @@ define i8 @phi_no_store_2() {
; IS__CGSCC_OPM: loop:
; IS__CGSCC_OPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a2 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
; IS__CGSCC_OPM-NEXT: [[I:%.*]] = phi i8 [ 0, [[ENTRY]] ], [ [[O:%.*]], [[LOOP]] ]
; IS__CGSCC_OPM-NEXT: store i8 1, i8* [[P]], align 2
; IS__CGSCC_OPM-NEXT: [[G]] = getelementptr i8, i8* bitcast (i32* @a2 to i8*), i64 2
; IS__CGSCC_OPM-NEXT: [[O]] = add nsw i8 [[I]], 1
; IS__CGSCC_OPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__CGSCC_OPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__CGSCC_OPM: end:
; IS__CGSCC_OPM-NEXT: [[L21:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 2), align 2
; IS__CGSCC_OPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], 0
; IS__CGSCC_OPM-NEXT: [[L22:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 3), align 1
; IS__CGSCC_OPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], [[L22]]
; IS__CGSCC_OPM-NEXT: ret i8 [[ADD]]
;
; IS__CGSCC_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn
@ -3122,14 +3122,14 @@ define i8 @phi_no_store_2() {
; IS__CGSCC_NPM: loop:
; IS__CGSCC_NPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a2 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
; IS__CGSCC_NPM-NEXT: [[I:%.*]] = phi i8 [ 0, [[ENTRY]] ], [ [[O:%.*]], [[LOOP]] ]
; IS__CGSCC_NPM-NEXT: store i8 1, i8* [[P]], align 2
; IS__CGSCC_NPM-NEXT: [[G]] = getelementptr i8, i8* bitcast (i32* @a2 to i8*), i64 2
; IS__CGSCC_NPM-NEXT: [[O]] = add nsw i8 [[I]], 1
; IS__CGSCC_NPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__CGSCC_NPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__CGSCC_NPM: end:
; IS__CGSCC_NPM-NEXT: [[L21:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 2), align 2
; IS__CGSCC_NPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], 0
; IS__CGSCC_NPM-NEXT: [[L22:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a2 to i8*), i64 3), align 1
; IS__CGSCC_NPM-NEXT: [[ADD:%.*]] = add i8 [[L21]], [[L22]]
; IS__CGSCC_NPM-NEXT: ret i8 [[ADD]]
;
entry:
@ -3153,10 +3153,11 @@ end:
}
define i8 @phi_no_store_3() {
; IS__TUNIT_OPM: Function Attrs: nofree norecurse nosync nounwind writeonly
; IS__TUNIT_OPM: Function Attrs: nofree norecurse nosync nounwind
; IS__TUNIT_OPM-LABEL: define {{[^@]+}}@phi_no_store_3
; IS__TUNIT_OPM-SAME: () #[[ATTR7]] {
; IS__TUNIT_OPM-SAME: () #[[ATTR3]] {
; IS__TUNIT_OPM-NEXT: entry:
; IS__TUNIT_OPM-NEXT: store i8 0, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__TUNIT_OPM-NEXT: br label [[LOOP:%.*]]
; IS__TUNIT_OPM: loop:
; IS__TUNIT_OPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a3 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
@ -3166,12 +3167,18 @@ define i8 @phi_no_store_3() {
; IS__TUNIT_OPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__TUNIT_OPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__TUNIT_OPM: end:
; IS__TUNIT_OPM-NEXT: ret i8 1
; IS__TUNIT_OPM-NEXT: [[L31:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 2), align 2
; IS__TUNIT_OPM-NEXT: [[L32:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__TUNIT_OPM-NEXT: [[ADD:%.*]] = add i8 [[L31]], [[L32]]
; IS__TUNIT_OPM-NEXT: [[L34:%.*]] = load i8, i8* bitcast (i32* getelementptr inbounds (i32, i32* @a3, i64 1) to i8*), align 4
; IS__TUNIT_OPM-NEXT: [[ADD2:%.*]] = add i8 [[ADD]], [[L34]]
; IS__TUNIT_OPM-NEXT: ret i8 [[ADD2]]
;
; IS__TUNIT_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn writeonly
; IS__TUNIT_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn
; IS__TUNIT_NPM-LABEL: define {{[^@]+}}@phi_no_store_3
; IS__TUNIT_NPM-SAME: () #[[ATTR5]] {
; IS__TUNIT_NPM-SAME: () #[[ATTR3]] {
; IS__TUNIT_NPM-NEXT: entry:
; IS__TUNIT_NPM-NEXT: store i8 0, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__TUNIT_NPM-NEXT: br label [[LOOP:%.*]]
; IS__TUNIT_NPM: loop:
; IS__TUNIT_NPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a3 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
@ -3181,12 +3188,18 @@ define i8 @phi_no_store_3() {
; IS__TUNIT_NPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__TUNIT_NPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__TUNIT_NPM: end:
; IS__TUNIT_NPM-NEXT: ret i8 1
; IS__TUNIT_NPM-NEXT: [[L31:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 2), align 2
; IS__TUNIT_NPM-NEXT: [[L32:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__TUNIT_NPM-NEXT: [[ADD:%.*]] = add i8 [[L31]], [[L32]]
; IS__TUNIT_NPM-NEXT: [[L34:%.*]] = load i8, i8* bitcast (i32* getelementptr inbounds (i32, i32* @a3, i64 1) to i8*), align 4
; IS__TUNIT_NPM-NEXT: [[ADD2:%.*]] = add i8 [[ADD]], [[L34]]
; IS__TUNIT_NPM-NEXT: ret i8 [[ADD2]]
;
; IS__CGSCC_OPM: Function Attrs: nofree norecurse nosync nounwind writeonly
; IS__CGSCC_OPM: Function Attrs: nofree norecurse nosync nounwind
; IS__CGSCC_OPM-LABEL: define {{[^@]+}}@phi_no_store_3
; IS__CGSCC_OPM-SAME: () #[[ATTR10:[0-9]+]] {
; IS__CGSCC_OPM-SAME: () #[[ATTR9]] {
; IS__CGSCC_OPM-NEXT: entry:
; IS__CGSCC_OPM-NEXT: store i8 0, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__CGSCC_OPM-NEXT: br label [[LOOP:%.*]]
; IS__CGSCC_OPM: loop:
; IS__CGSCC_OPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a3 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
@ -3196,12 +3209,18 @@ define i8 @phi_no_store_3() {
; IS__CGSCC_OPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__CGSCC_OPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__CGSCC_OPM: end:
; IS__CGSCC_OPM-NEXT: ret i8 1
; IS__CGSCC_OPM-NEXT: [[L31:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 2), align 2
; IS__CGSCC_OPM-NEXT: [[L32:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__CGSCC_OPM-NEXT: [[ADD:%.*]] = add i8 [[L31]], [[L32]]
; IS__CGSCC_OPM-NEXT: [[L34:%.*]] = load i8, i8* bitcast (i32* getelementptr inbounds (i32, i32* @a3, i64 1) to i8*), align 4
; IS__CGSCC_OPM-NEXT: [[ADD2:%.*]] = add i8 [[ADD]], [[L34]]
; IS__CGSCC_OPM-NEXT: ret i8 [[ADD2]]
;
; IS__CGSCC_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn writeonly
; IS__CGSCC_NPM: Function Attrs: nofree norecurse nosync nounwind willreturn
; IS__CGSCC_NPM-LABEL: define {{[^@]+}}@phi_no_store_3
; IS__CGSCC_NPM-SAME: () #[[ATTR7]] {
; IS__CGSCC_NPM-SAME: () #[[ATTR5]] {
; IS__CGSCC_NPM-NEXT: entry:
; IS__CGSCC_NPM-NEXT: store i8 0, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__CGSCC_NPM-NEXT: br label [[LOOP:%.*]]
; IS__CGSCC_NPM: loop:
; IS__CGSCC_NPM-NEXT: [[P:%.*]] = phi i8* [ bitcast (i32* @a3 to i8*), [[ENTRY:%.*]] ], [ [[G:%.*]], [[LOOP]] ]
@ -3211,7 +3230,12 @@ define i8 @phi_no_store_3() {
; IS__CGSCC_NPM-NEXT: [[C:%.*]] = icmp eq i8 [[O]], 7
; IS__CGSCC_NPM-NEXT: br i1 [[C]], label [[END:%.*]], label [[LOOP]]
; IS__CGSCC_NPM: end:
; IS__CGSCC_NPM-NEXT: ret i8 1
; IS__CGSCC_NPM-NEXT: [[L31:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 2), align 2
; IS__CGSCC_NPM-NEXT: [[L32:%.*]] = load i8, i8* getelementptr (i8, i8* bitcast (i32* @a3 to i8*), i64 3), align 1
; IS__CGSCC_NPM-NEXT: [[ADD:%.*]] = add i8 [[L31]], [[L32]]
; IS__CGSCC_NPM-NEXT: [[L34:%.*]] = load i8, i8* bitcast (i32* getelementptr inbounds (i32, i32* @a3, i64 1) to i8*), align 4
; IS__CGSCC_NPM-NEXT: [[ADD2:%.*]] = add i8 [[ADD]], [[L34]]
; IS__CGSCC_NPM-NEXT: ret i8 [[ADD2]]
;
entry:
%b = bitcast i32* @a3 to i8*
@ -3232,7 +3256,10 @@ end:
%s32 = getelementptr i8, i8* %b, i64 3
%l32 = load i8, i8* %s32
%add = add i8 %l31, %l32
ret i8 %add
%s34 = getelementptr i8, i8* %b, i64 4
%l34 = load i8, i8* %s34
%add2 = add i8 %add, %l34
ret i8 %add2
}
define i8 @cast_and_load_1() {
@ -3296,7 +3323,7 @@ define void @recursive_load_store(i64 %N, i32 %v) {
;
; IS__CGSCC_OPM: Function Attrs: nofree norecurse nosync nounwind writeonly
; IS__CGSCC_OPM-LABEL: define {{[^@]+}}@recursive_load_store
; IS__CGSCC_OPM-SAME: (i64 [[N:%.*]], i32 [[V:%.*]]) #[[ATTR10]] {
; IS__CGSCC_OPM-SAME: (i64 [[N:%.*]], i32 [[V:%.*]]) #[[ATTR10:[0-9]+]] {
; IS__CGSCC_OPM-NEXT: entry:
; IS__CGSCC_OPM-NEXT: br label [[FOR_COND:%.*]]
; IS__CGSCC_OPM: for.cond: