Use current BFP rounding mode for s390x integer-to-double conversion - #131840
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Use current BFP rounding mode for s390x integer-to-double conversion#131840abhishekabhi73cc-design wants to merge 1 commit into
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Why make this change? It seems like its strictly worse and risks introducing breakage for scenarios where the floating-point control word is modified. If there is a form that allows strictly specifying the dedicated rounding mode per instruction, that seems like pure goodness (and on other architectures can actually be a minor perf improvement). |
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The previous implementation explicitly encoded round-to-nearest, ties-to-even (
M3 = 4) for the s390x integer-to-double conversion.This change switches to
M3 = 0, allowing the instruction to use the current BFP rounding mode. Since the CLI initializes the floating-point environment to IEEE-754 round-to-nearest and managed code cannot modify it, this preserves the required semantics while relying on the runtime-configured floating-point control state.Verified by the existing BigInteger conversion regression tests.