Skip to content

[ValueTracking] Handle intrinsics in computeConstantRange #100870

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 2 commits into from
Closed

[ValueTracking] Handle intrinsics in computeConstantRange #100870

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
164a578
[ValueTracking] Add pre-commit tests. NFC.
dtcxzyw Jul 27, 2024
bec3496
[ValueTracking] Handle intrinsics in `computeConstantRange`
dtcxzyw Jul 27, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 14 additions & 3 deletions llvm/lib/Analysis/ValueTracking.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9687,12 +9687,12 @@ ConstantRange llvm::computeConstantRange(const Value *V, bool ForSigned,
unsigned Depth) {
assert(V->getType()->isIntOrIntVectorTy() && "Expected integer instruction");

if (Depth == MaxAnalysisRecursionDepth)
return ConstantRange::getFull(V->getType()->getScalarSizeInBits());

if (auto *C = dyn_cast<Constant>(V))
return C->toConstantRange();

if (Depth == MaxAnalysisRecursionDepth)
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Related test: @immarg_test

return ConstantRange::getFull(V->getType()->getScalarSizeInBits());

unsigned BitWidth = V->getType()->getScalarSizeInBits();
InstrInfoQuery IIQ(UseInstrInfo);
ConstantRange CR = ConstantRange::getFull(BitWidth);
Expand Down Expand Up @@ -9728,6 +9728,17 @@ ConstantRange llvm::computeConstantRange(const Value *V, bool ForSigned,
if (const auto *CB = dyn_cast<CallBase>(V))
if (std::optional<ConstantRange> Range = CB->getRange())
CR = CR.intersectWith(*Range);

if (const auto *II = dyn_cast<IntrinsicInst>(V)) {
Intrinsic::ID IID = II->getIntrinsicID();
if (ConstantRange::isIntrinsicSupported(IID)) {
SmallVector<ConstantRange, 2> OpRanges;
for (Value *Op : II->args())
OpRanges.push_back(computeConstantRange(Op, ForSigned, UseInstrInfo,
AC, CtxI, DT, Depth + 1));
CR = CR.intersectWith(ConstantRange::intrinsic(IID, OpRanges));
}
}
Copy link
Contributor

@nikic nikic Jul 27, 2024 •
edited
Loading

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Placing the code here doesn't makes sense, there is already getRangeForIntrinsic above.

}

if (CtxI && AC) {
Expand Down
69 changes: 69 additions & 0 deletions llvm/test/Analysis/ValueTracking/constant-ranges.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -230,3 +230,72 @@ define i1 @srem_negC_fail1(i8 %x) {
%r = icmp sge i8 %val, -33
ret i1 %r
}

define i1 @intrinsic_test1(i64 %x, i32 %y, i64 %z) {
; CHECK-LABEL: @intrinsic_test1(
; CHECK-NEXT: ret i1 false
;
%sh_prom = zext nneg i32 %y to i64
%shl = shl nuw i64 1, %sh_prom
%cmp1 = icmp eq i64 %z, 0
%umin1 = call i64 @llvm.umin.i64(i64 %shl, i64 %z)
%sel = select i1 %cmp1, i64 1, i64 %umin1
%umin2 = call i64 @llvm.umin.i64(i64 %x, i64 %sel)
%cmp = icmp ugt i64 %umin2, -71777214294589697
ret i1 %cmp
}
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Won't this case already be handled by CVP with the shl nuw support from #100594?


define i1 @intrinsic_test2(i32 %x, i32 %y) {
; CHECK-LABEL: @intrinsic_test2(
; CHECK-NEXT: [[SH:%.*]] = shl nuw nsw i32 16, [[X:%.*]]
; CHECK-NEXT: [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[SH]], i32 64)
; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i32 [[Y:%.*]], 1
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[ADD]], [[UMIN]]
; CHECK-NEXT: ret i1 [[CMP]]
;
%sh = shl nuw nsw i32 16, %x
%umin = call i32 @llvm.umin.i32(i32 %sh, i32 64)
%umax = call i32 @llvm.umax.i32(i32 %umin, i32 1)
%add = add nuw nsw i32 %y, 1
%cmp = icmp eq i32 %add, %umax
ret i1 %cmp
}

define i1 @constant_test(i64 %x, i1 %cond) {
; CHECK-LABEL: @constant_test(
; CHECK-NEXT: [[SEL:%.*]] = select i1 [[COND:%.*]], i64 2147483647, i64 18446744073709551
; CHECK-NEXT: [[CMP2:%.*]] = icmp ugt i64 [[X:%.*]], [[SEL]]
; CHECK-NEXT: ret i1 [[CMP2]]
;
%sel = select i1 %cond, i64 2147483647, i64 18446744073709551
%cmp1 = icmp slt i64 %x, 0
%cmp2 = icmp ugt i64 %x, %sel
%or.cond = or i1 %cmp1, %cmp2
ret i1 %or.cond
}

; Make sure that we don't return a full range for an imm arg.
define i1 @immarg_test(i32 %x, i32 %y, i1 %c1, i1 %c2, i1 %c3, i1 %c4, i1 %c5, i1 %c6, i1 %c7) {
; CHECK-LABEL: @immarg_test(
; CHECK-NEXT: [[ABS:%.*]] = call i32 @llvm.abs.i32(i32 [[Y:%.*]], i1 true)
; CHECK-NEXT: [[M1:%.*]] = select i1 [[C1:%.*]], i32 [[ABS]], i32 0
; CHECK-NEXT: [[M2:%.*]] = select i1 [[C2:%.*]], i32 [[M1]], i32 1
; CHECK-NEXT: [[M3:%.*]] = select i1 [[C3:%.*]], i32 [[M2]], i32 2
; CHECK-NEXT: [[M4:%.*]] = select i1 [[C4:%.*]], i32 [[M3]], i32 3
; CHECK-NEXT: [[M5:%.*]] = select i1 [[C5:%.*]], i32 [[M4]], i32 4
; CHECK-NEXT: [[M6:%.*]] = select i1 [[C6:%.*]], i32 [[M5]], i32 5
; CHECK-NEXT: [[M7:%.*]] = select i1 [[C7:%.*]], i32 [[M6]], i32 6
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[M7]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
%abs = call i32 @llvm.abs.i32(i32 %y, i1 true)
%m1 = select i1 %c1, i32 %abs, i32 0
%m2 = select i1 %c2, i32 %m1, i32 1
%m3 = select i1 %c3, i32 %m2, i32 2
%m4 = select i1 %c4, i32 %m3, i32 3
%m5 = select i1 %c5, i32 %m4, i32 4
%m6 = select i1 %c6, i32 %m5, i32 5
%m7 = select i1 %c7, i32 %m6, i32 6
%cmp = icmp eq i32 %m7, 1
ret i1 %cmp
}
2 changes: 1 addition & 1 deletion llvm/test/Transforms/InstCombine/sub.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1329,7 +1329,7 @@ define <2 x i32> @test68(<2 x i32> %x) {
define <2 x i32> @test69(<2 x i32> %x) {
; CHECK-LABEL: @test69(
; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i32> @llvm.smin.v2i32(<2 x i32> [[X:%.*]], <2 x i32> <i32 255, i32 127>)
; CHECK-NEXT: [[DOTNEG:%.*]] = add <2 x i32> [[TMP1]], <i32 1, i32 1>
; CHECK-NEXT: [[DOTNEG:%.*]] = add nsw <2 x i32> [[TMP1]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i32> [[DOTNEG]]
;
%1 = xor <2 x i32> %x, <i32 -1, i32 -1>
Expand Down
8 changes: 2 additions & 6 deletions llvm/test/Transforms/InstSimplify/call.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1582,9 +1582,7 @@ define i1 @ctlz_i1_non_poison_eq_false(i1 %x) {

define i1 @ctlz_i1_poison_eq_false(i1 %x) {
; CHECK-LABEL: @ctlz_i1_poison_eq_false(
; CHECK-NEXT: [[CT:%.*]] = call i1 @llvm.ctlz.i1(i1 [[X:%.*]], i1 true)
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i1 [[CT]], false
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
%ct = call i1 @llvm.ctlz.i1(i1 %x, i1 true)
%cmp = icmp eq i1 %ct, false
Expand All @@ -1604,9 +1602,7 @@ define i1 @cttz_i1_non_poison_eq_false(i1 %x) {

define i1 @cttz_i1_poison_eq_false(i1 %x) {
; CHECK-LABEL: @cttz_i1_poison_eq_false(
; CHECK-NEXT: [[CT:%.*]] = call i1 @llvm.cttz.i1(i1 [[X:%.*]], i1 true)
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i1 [[CT]], false
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
%ct = call i1 @llvm.cttz.i1(i1 %x, i1 true)
%cmp = icmp eq i1 %ct, false
Expand Down
Loading