[mlir][spirv] Check variable for null before dereferencing

[apach301]

FIxes #157453

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-spirv

Author: Daniel Kuts (apach301)

Changes

FIxes #157453

---

Full diff: https://github.com/llvm/llvm-project/pull/157457.diff

1 Files Affected:

• (modified) mlir/lib/Dialect/SPIRV/IR/SPIRVOps.cpp (+2-2)

diff --git a/mlir/lib/Dialect/SPIRV/IR/SPIRVOps.cpp b/mlir/lib/Dialect/SPIRV/IR/SPIRVOps.cpp
index f99339852824c..7a6d4a212159b 100644
--- a/mlir/lib/Dialect/SPIRV/IR/SPIRVOps.cpp
+++ b/mlir/lib/Dialect/SPIRV/IR/SPIRVOps.cpp
@@ -727,9 +727,9 @@ void mlir::spirv::ConstantOp::getAsmResultNames(
       return setNameFn(getResult(), (intCst.getInt() ? "true" : "false"));
     }
 
-    if (intTy.isSignless()) {
+    if (intTy && intTy.isSignless()) {
       specialName << intCst.getInt();
-    } else if (intTy.isUnsigned()) {
+    } else if (intTy && intTy.isUnsigned()) {
       specialName << intCst.getUInt();
     } else {
       specialName << intCst.getSInt();

[kuhar]

I don't understand when this could happen. Could you add a lit test? If the value is an integer attr, the type must be either bool or int, no?

[apach301]

I don't understand when this could happen. Could you add a lit test? If the value is an integer attr, the type must be either bool or int, no?

The problem is that intTy could be NULL after dynamic cast, there are checks in code for this (lines 726, 739), except these 2 cases (calling isSignless and isUnsigned). Can't add a test cause it was a static analyzer, I don't know how to trigger exact this code

[kuhar]

I don't think it can inside the if statement that checks for IntegerAttr. If anything, we can probably remove the null check on line 726 (and maybe turn it into an assertion to be explicit).

[kuhar]

LGTM if the CI passes