[compiler-rt] Don't raise Inexact exception in C FP add implementation #111211
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It would be lovely if the soft float implementation were extended to fully support all IEEE exceptions and rounding modes. However, at present, there is only a single place where one exception might be raised: the C version of addition raises Inexact when the result differs from the precise value. This affects targets which have hardware support for some formats and rely on software for other formats; those will expose an implementation of __fe_raise_inexact() that modifies the FPU status register. Removing the Inexact exception generation from the C version of FP addition makes the implementation consistent across all operations and formats on all targets. In addition, it makes the implementation match the semantics of libgcc. Signed-off-by: Keith Packard <[email protected]>
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It would be lovely if the soft float implementation were extended to fully support all IEEE exceptions and rounding modes. However, at present, there is only a single place where one exception might be raised: the C version of addition raises Inexact when the result differs from the precise value.
This affects targets which have hardware support for some formats and rely on software for other formats; those will expose an implementation of __fe_raise_inexact() that modifies the FPU status register.
Removing the Inexact exception generation from the C version of FP addition makes the implementation consistent across all operations and formats on all targets. In addition, it makes the implementation match the semantics of libgcc on 32-bit arm.