[LLVM] Fix a bug in Intrinsic::getFnAttributes
#161248
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When an intrinsic has no function attributes, the current code will hit an assert in `getIntrinsicFnAttributeSet`. Fix this by checking for the sentinel `NoFunctionAttrsID` value and returning an empty attribute set.
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@llvm/pr-subscribers-tablegen @llvm/pr-subscribers-llvm-ir Author: Rahul Joshi (jurahul) ChangesWhen an intrinsic has no function attributes, the current code will hit an assert in Full diff: https://github.com/llvm/llvm-project/pull/161248.diff 2 Files Affected:
diff --git a/llvm/unittests/IR/IntrinsicsTest.cpp b/llvm/unittests/IR/IntrinsicsTest.cpp
index 49af83609d98c..cfd99ed542162 100644
--- a/llvm/unittests/IR/IntrinsicsTest.cpp
+++ b/llvm/unittests/IR/IntrinsicsTest.cpp
@@ -189,4 +189,12 @@ TEST_F(IntrinsicsTest, InstrProfInheritance) {
}
}
+// Check that getFnAttributes for intrinsics that do not have any function
+// attributes correcty returns an empty set.
+TEST(IntrinsicAttributes, TestGetFnAttributesBug) {
+ using namespace Intrinsic;
+ LLVMContext Context;
+ AttributeSet AS = getFnAttributes(Context, experimental_guard);
+ EXPECT_FALSE(AS.hasAttributes());
+}
} // end namespace
diff --git a/llvm/utils/TableGen/Basic/IntrinsicEmitter.cpp b/llvm/utils/TableGen/Basic/IntrinsicEmitter.cpp
index 559868dd54efe..75dffb18fca5a 100644
--- a/llvm/utils/TableGen/Basic/IntrinsicEmitter.cpp
+++ b/llvm/utils/TableGen/Basic/IntrinsicEmitter.cpp
@@ -794,12 +794,15 @@ AttributeSet Intrinsic::getFnAttributes(LLVMContext &C, ID id) {{
if (id == 0)
return AttributeSet();
auto [FnAttrID, _] = unpackID(IntrinsicsToAttributesMap[id - 1]);
+ if (FnAttrID == {})
+ return AttributeSet();
return getIntrinsicFnAttributeSet(C, FnAttrID);
}
#endif // GET_INTRINSIC_ATTRIBUTES
)",
- UniqAttributesBitSize, MaxNumAttrs, NoFunctionAttrsID);
+ UniqAttributesBitSize, MaxNumAttrs, NoFunctionAttrsID,
+ NoFunctionAttrsID);
}
void IntrinsicEmitter::EmitIntrinsicToBuiltinMap(
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nikic
approved these changes
Sep 29, 2025
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LGTM. Alternatively we could make the "no fn attrs" case less special by getIntrinsicFnAttributeSet() handle that by returning an empty attribute set -- but we'd probably still want an explicit check in getAttributes() to avoid pushing the FunctionIndex, so maybe that's not worthwhile.
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Just want to mention that this bug was flagged by an AI assisted code review tool internally. |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/16422 Here is the relevant piece of the build log for the reference |
mahesh-attarde
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Oct 3, 2025
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When an intrinsic has no function attributes, the current code will hit an assert in
getIntrinsicFnAttributeSet. Fix this by checking for the sentinelNoFunctionAttrsIDvalue and returning an empty attribute set.