Fix __hexagon_fmadf5 overflow under directed rounding - #1281
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tgross35 merged 1 commit intoAug 17, 2026
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The overflow path in __hexagon_fmadf5 computed the round-mode predicate (inf vs. largest-finite) into p0, but then overwrote p0 with `dfcmp.eq(ATMP,ATMP)` before consuming it. Since ATMP is +inf, `dfcmp.eq(ATMP,ATMP)` is always true, so CTMP was unconditionally set to infinity and the rounding-mode decision was discarded. As a result, a finite-magnitude overflow returned +/-inf in every rounding mode. Signed-off-by: Zain Siddavatam <zsiddava@qti.qualcomm.com>
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@androm3da could you review this? |
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LGTM: corresponds to llvm/llvm-project#207373 |
androm3da
approved these changes
Aug 15, 2026
tgross35
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Aug 17, 2026
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The overflow path in __hexagon_fmadf5 computed the round-mode predicate (inf vs. largest-finite) into p0, but then overwrote p0 with
dfcmp.eq(ATMP,ATMP)before consuming it. Since ATMP is +inf,dfcmp.eq(ATMP,ATMP)is always true, so CTMP was unconditionally set to infinity and the rounding-mode decision was discarded.As a result, a finite-magnitude overflow returned +/-inf in every rounding mode.