CommonCompareExpressionRewrite: place the negation after the op it reads - #2995
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When the negated twin appears after the matched compare, the NotOp was created at the rewriter's default insertion point — before the compare whose result it reads — producing IR that fails dominance verification. Found via mfem QuadratureInterpolator raised kernels (#2968), where the masked strip-loop bounds emit LE/GT pairs on the same operands. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_016zErYp7upmqr4NHfhod9UD
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When
CommonCompareExpressionRewritefinds the negated twin after the matched compare, it created theNotOpat the rewriter's default insertion point — before the compare whose result it reads — producing IR that fails dominance verification (operand #0 does not dominate this use).Hit by mfem's QuadratureInterpolator raised kernels under the XLA backend (#2968): masked strip-loop bounds emit
LE/GTpairs on the same operands in one block, and whether the bad arm fires depends on block order, so it surfaced as a nondeterministic compile failure.Fix: guard the insertion point and place the negation at the later compare's position. Lit test included (fails dominance verification without the fix).
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https://claude.ai/code/session_016zErYp7upmqr4NHfhod9UD