Fix VSX rounding#1320
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serge-sans-paille merged 1 commit intoxtensor-stack:masterfrom Apr 24, 2026
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This fixes a problem with rounding in the VSX support revealed by #1318
vec_round on Power unfortunately behaves inconsistently across different data types:
For float vectors vec_round is implemented by vrfin. vrfin uses "round to nearest with ties to even" which does NOT match the std::round rounding mode (ties away form zero)
For double vectors however, vec_round is implemented by xvrdpi which uses the std::round rounding mode.
So far this went unnoticed because test_rounding only tested the first four input values for float vectors. For these four values the rounding mode difference doesn't change anything. test_rounding fails with #1318 and with this PR it is clean again on IBM Power. Tested on a Power10 system.