yunho-c opened a new issue, #18585:
URL: https://github.com/apache/tvm/issues/18585
### Expected behavior
TVM should successfully compile and build Relax models targeting LLVM
backends when using LLVM 15+ (including LLVM 21).
### Actual behavior
When building a model with fused kernels containing operations like
`instance_norm`, LLVM module verification fails with:
```
LLVM module verification failed: location of #dbg_declare must be a pointer
or int
```
This occurs specifically with fused functions like:
- `fused_add*_instance_norm*_multiply*_leaky_relu*_compute_`
### Environment
- **TVM Version**: main branch (commit hash: `fc2bdfe`)
- **LLVM Version**: 21.1.6 (likely affects LLVM 15-20 also)
- **Operating System**: macOS 15.6 (may affect Linux also)
- **Target**: `llvm -mtriple=arm64-apple-macosx`
- **Python**: 3.12
### Steps to reproduce
`tvm_llvm_dbg_declare_bug_repro.py`
```python
import torch
import tvm
from tvm import relax
from tvm.relax.frontend.torch import from_exported_program
# Any model with InstanceNorm will trigger this
class Model(torch.nn.Module):
def __init__(self):
super().__init__()
self.norm = torch.nn.InstanceNorm1d(256)
def forward(self, x):
return self.norm(x)
model = Model().eval()
example_input = torch.randn(1, 256, 100)
# Export and import to TVM
with torch.no_grad():
exported = torch.export.export(model, (example_input,))
mod = from_exported_program(exported)
# Apply standard optimizations
mod = relax.transform.DecomposeOpsForInference()(mod)
mod = relax.transform.LegalizeOps()(mod)
mod = relax.transform.FuseOps()(mod)
mod = relax.transform.FuseTIR()(mod)
# Build - this crashes with LLVM 15+
target = tvm.target.Target("llvm")
ex = relax.build(mod, target) # LLVM verification error here
```
### Analysis
The issue seems to be in `src/target/llvm/codegen_llvm.cc`, function
`AddDebugInformation` (lines 2311-2342).
#### Problem
`AddDebugInformation` calls `insertDeclare` on **any** `llvm::Value*`,
including floating-point values:
```cpp
void CodeGenLLVM::AddDebugInformation(llvm::Value* llvm_value, const Var&
tir_var, ...) {
// ...
// No check if llvm_value is a pointer or integer!
dbg_info_->di_builder_->insertDeclare(llvm_value, local_var, ...); // ←
fails on floats
}
```
LLVM 15+ added stricter verification for `#dbg_declare` intrinsics,
requiring that the first operand be a pointer or integer type. When TVM emits
debug info for floating-point reduction temporaries (e.g., in `instance_norm`
fused kernels), LLVM's verifier rejects the module.
#### Call Sites
The function is called from:
1. `VisitExpr_(const LetNode* op)` - line 1722
2. `VisitStmt_(const LetStmtNode* op)` - lines 2203, 2210
3. `VisitStmt_(const AllocateNode* op)` - line 2137
When processing `LetNode` for float temporaries in reduction operations,
`AddDebugInformation` receives a float `llvm::Value*` and attempts to attach
debug info, which fails verification.
### Reference
- https://llvm.org/docs/SourceLevelDebugging.html#dbg-declare
### Triage
* llvm
* type: bug
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