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Sep 24, 2025
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[IR] Forbid mixing condition and operand bundle assumes #160460

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b932cfc
[IR] Forbid mixing condition and bundle assumes
nikic Sep 24, 2025
ef963eb
Update MLIR tests
nikic Sep 24, 2025
de14f87
Restore test
nikic Sep 24, 2025
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4 changes: 3 additions & 1 deletion llvm/docs/LangRef.rst
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Expand Up @@ -3013,6 +3013,8 @@ assumptions, such as that a :ref:`parameter attribute <paramattrs>` or a
location. Operand bundles enable assumptions that are either hard or impossible
to represent as a boolean argument of an :ref:`llvm.assume <int_assume>`.

Assumes with operand bundles must have ``i1 true`` as the condition operand.

An assume operand bundle has the form:

::
Expand Down Expand Up @@ -3045,7 +3047,7 @@ allows the optimizer to assume that at location of call to

.. code-block:: llvm

call void @llvm.assume(i1 %cond) ["cold"(), "nonnull"(ptr %val)]
call void @llvm.assume(i1 true) ["cold"(), "nonnull"(ptr %val)]

allows the optimizer to assume that the :ref:`llvm.assume <int_assume>`
call location is cold and that ``%val`` may not be null.
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5 changes: 5 additions & 0 deletions llvm/lib/IR/Verifier.cpp
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Expand Up @@ -5675,6 +5675,11 @@ void Verifier::visitIntrinsicCall(Intrinsic::ID ID, CallBase &Call) {
default:
break;
case Intrinsic::assume: {
if (Call.hasOperandBundles()) {
auto *Cond = dyn_cast<ConstantInt>(Call.getArgOperand(0));
Check(Cond && Cond->isOne(),
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I guess this could use m_One(), but not sure if it would be really more compact

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I considered this, but we currently don't use PatternMatch at all inside the Verifier, so I stuck with the existing style.

"assume with operand bundles must have i1 true condition", Call);
}
for (auto &Elem : Call.bundle_op_infos()) {
unsigned ArgCount = Elem.End - Elem.Begin;
// Separate storage assumptions are special insofar as they're the only
Expand Down
4 changes: 2 additions & 2 deletions llvm/test/Transforms/AlignmentFromAssumptions/domtree-crash.ll
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Expand Up @@ -9,10 +9,10 @@

define void @fn1() {
; CHECK-LABEL: define void @fn1() {
; CHECK-NEXT: call void @llvm.assume(i1 false) [ "align"(ptr @global, i64 1) ]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "align"(ptr @global, i64 1) ]
; CHECK-NEXT: ret void
;
call void @llvm.assume(i1 false) [ "align"(ptr @global, i64 1) ]
call void @llvm.assume(i1 true) [ "align"(ptr @global, i64 1) ]
ret void
}

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16 changes: 8 additions & 8 deletions llvm/test/Transforms/InstCombine/assume.ll
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Expand Up @@ -498,24 +498,24 @@ not_taken:
define i1 @nonnull3B(ptr %a, i1 %control) {
; CHECK-LABEL: @nonnull3B(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LOAD:%.*]] = load ptr, ptr [[A:%.*]], align 8
; CHECK-NEXT: br i1 [[CONTROL:%.*]], label [[TAKEN:%.*]], label [[NOT_TAKEN:%.*]]
; CHECK: taken:
; CHECK-NEXT: [[LOAD:%.*]] = load ptr, ptr [[A:%.*]], align 8
; CHECK-NEXT: [[CMP:%.*]] = icmp ne ptr [[LOAD]], null
; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) [ "nonnull"(ptr [[LOAD]]) ]
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "nonnull"(ptr [[LOAD]]) ]
; CHECK-NEXT: ret i1 true
; CHECK: not_taken:
; CHECK-NEXT: call void @llvm.assume(i1 true) [ "nonnull"(ptr [[LOAD]]) ]
; CHECK-NEXT: ret i1 false
;
entry:
%load = load ptr, ptr %a
%cmp = icmp ne ptr %load, null
br i1 %control, label %taken, label %not_taken
taken:
call void @llvm.assume(i1 %cmp) ["nonnull"(ptr %load)]
call void @llvm.assume(i1 true) ["nonnull"(ptr %load)]
ret i1 %cmp
not_taken:
call void @llvm.assume(i1 %cmp) ["nonnull"(ptr %load)]
call void @llvm.assume(i1 true) ["nonnull"(ptr %load)]
ret i1 %control
}

Expand Down Expand Up @@ -544,7 +544,7 @@ taken:
br label %exit
exit:
; FIXME: this shouldn't be dropped because it is still dominated by the new position of %load
call void @llvm.assume(i1 %cmp) ["nonnull"(ptr %load)]
call void @llvm.assume(i1 %cmp)
ret i1 %cmp2
not_taken:
call void @llvm.assume(i1 %cmp)
Expand Down Expand Up @@ -575,7 +575,7 @@ taken:
exit:
ret i1 %cmp2
not_taken:
call void @llvm.assume(i1 %cmp) ["nonnull"(ptr %load)]
call void @llvm.assume(i1 %cmp)
ret i1 %control
}

Expand Down
4 changes: 3 additions & 1 deletion llvm/test/Verifier/assume-bundles.ll
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Expand Up @@ -3,7 +3,7 @@

declare void @llvm.assume(i1)

define void @func(ptr %P, i32 %P1, ptr %P2, ptr %P3) {
define void @func(ptr %P, i32 %P1, ptr %P2, ptr %P3, i1 %cond) {
; CHECK: tags must be valid attribute names
; CHECK: "adazdazd"
call void @llvm.assume(i1 true) ["adazdazd"()]
Expand Down Expand Up @@ -32,5 +32,7 @@ define void @func(ptr %P, i32 %P1, ptr %P2, ptr %P3) {
call void @llvm.assume(i1 true) ["separate_storage"(ptr %P, i32 123)]
; CHECK: dereferenceable assumptions should have 2 arguments
call void @llvm.assume(i1 true) ["align"(ptr %P, i32 4), "dereferenceable"(ptr %P)]
; CHECK: assume with operand bundles must have i1 true condition
call void @llvm.assume(i1 %cond) ["nonnull"(ptr %P)]
ret void
}
6 changes: 3 additions & 3 deletions mlir/test/Target/LLVMIR/Import/intrinsic.ll
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Expand Up @@ -733,12 +733,12 @@ define void @assume(i1 %true) {
}

; CHECK-LABEL: @assume_with_opbundles
; CHECK-SAME: %[[TRUE:[a-zA-Z0-9]+]]
; CHECK-SAME: %[[PTR:[a-zA-Z0-9]+]]
define void @assume_with_opbundles(i1 %true, ptr %p) {
define void @assume_with_opbundles(ptr %p) {
; CHECK: %[[TRUE:.+]] = llvm.mlir.constant(true) : i1
; CHECK: %[[ALIGN:.+]] = llvm.mlir.constant(8 : i32) : i32
; CHECK: llvm.intr.assume %[[TRUE]] ["align"(%[[PTR]], %[[ALIGN]] : !llvm.ptr, i32)] : i1
call void @llvm.assume(i1 %true) ["align"(ptr %p, i32 8)]
call void @llvm.assume(i1 true) ["align"(ptr %p, i32 8)]
ret void
}

Expand Down
7 changes: 4 additions & 3 deletions mlir/test/Target/LLVMIR/llvmir-intrinsics.mlir
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Expand Up @@ -460,10 +460,11 @@ llvm.func @assume_without_opbundles(%cond: i1) {
}

// CHECK-LABEL: @assume_with_opbundles
llvm.func @assume_with_opbundles(%cond: i1, %p: !llvm.ptr) {
llvm.func @assume_with_opbundles(%p: !llvm.ptr) {
%true = llvm.mlir.constant(true) : i1
%0 = llvm.mlir.constant(8 : i32) : i32
// CHECK: call void @llvm.assume(i1 %{{.+}}) [ "align"(ptr %{{.+}}, i32 8) ]
llvm.intr.assume %cond ["align"(%p, %0 : !llvm.ptr, i32)] : i1
// CHECK: call void @llvm.assume(i1 true) [ "align"(ptr %{{.+}}, i32 8) ]
llvm.intr.assume %true ["align"(%p, %0 : !llvm.ptr, i32)] : i1
llvm.return
}

Expand Down