This is an automated email from the ASF dual-hosted git repository.
tqchen pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/tvm-tirx.git
The following commit(s) were added to refs/heads/main by this push:
new 3c9fc462 [Fix] Preserve unsigned comparison semantics in
simplification (#13)
3c9fc462 is described below
commit 3c9fc462b5c818961bf29f2f0d0ca9e90f7bf009
Author: Tianqi Chen <[email protected]>
AuthorDate: Wed Oct 21 13:55:45 2026 -0400
[Fix] Preserve unsigned comparison semantics in simplification (#13)
Unsigned ordering cannot be reduced to subtraction because unsigned
subtraction may underflow. Keep unsigned comparisons on the direct
rewrite path instead of canonicalizing them through a difference.
Fixes apache/tvm-tirx#9.
---
src/sym/canonical_simplify.cc | 4 ++++
tests/python/sym/test_canonical_simplify.py | 5 +++++
2 files changed, 9 insertions(+)
diff --git a/src/sym/canonical_simplify.cc b/src/sym/canonical_simplify.cc
index 20e9d45b..afbb1538 100644
--- a/src/sym/canonical_simplify.cc
+++ b/src/sym/canonical_simplify.cc
@@ -1390,6 +1390,10 @@ UnchangedOr<PrimExpr>
CanonicalSimplifier::Impl::Mutate_(const prim::CastNode* o
UnchangedOr<PrimExpr> CanonicalSimplifier::Impl::Mutate_(const prim::LTNode*
op,
InplaceMode
inplace_mode) {
+ // Unsigned subtraction does not preserve comparison ordering.
+ if (op->a->ty.as_or_throw<PrimType>().MatchesCode(DLDataTypeCode::kDLUInt)) {
+ return Rewriter::Mutate_(op, inplace_mode);
+ }
// First convert a < b into a - b < 0
PrimExpr difference = op->a - op->b;
PrimExpr expr = DirectMutate(difference,
inplace_mode).ValueOrUnchanged(std::move(difference));
diff --git a/tests/python/sym/test_canonical_simplify.py
b/tests/python/sym/test_canonical_simplify.py
index f8a38295..5a9ac36f 100644
--- a/tests/python/sym/test_canonical_simplify.py
+++ b/tests/python/sym/test_canonical_simplify.py
@@ -411,6 +411,11 @@ def test_floormod_two():
ck.verify(flm(x * 10 + 1 + y * 2 + 2, 2), 1)
+def test_simplify_unsigned_comparison():
+ ck = CanonicalChecker()
+ ck.verify(tirx.Cast("uint8", T.uint8(1)) > tirx.Cast("uint8", T.uint8(0)),
T.bool(True))
+
+
def test_simplify_le():
ck = CanonicalChecker()
# Case 1. Ignore the extra expr if it's small than the division number
