Crossgen2 determinism fix and stress mode #87302
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To use this, pass --determinism-stress:<howManyTimesToReRunTheJIT> to the compiler. Also add use of this new mode to our crossgen2 comparison runs
Fixed by always zero-initializing the GenTreeVcon's gtSimdVal field The exact issue that I debugged to find was at https://github.com/dotnet/runtime/blob/d88f9a0ed3ac7387d4c16905ff279f4310c03667/src/coreclr/jit/importercalls.cpp#LL3538C1-L3547C18 In particular the issue is that the code constructs a vector constant, but does not zero out the entire constant.
jakobbotsch
approved these changes
Jun 9, 2023
10 was too big a number for the first runs through this.
ghost
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Fix determinism issue found in JIT
Fixed by always zero-initializing the GenTreeVcon's gtSimdVal field
The exact issue that I debugged to find was at
https://github.com/dotnet/runtime/blob/d88f9a0ed3ac7387d4c16905ff279f4310c03667/src/coreclr/jit/importercalls.cpp#LL3538C1-L3547C18 In particular the issue is that the code constructs a vector constant, but does not zero out the entire constant.
In addition, build a stress mode to make finding this sort of issue a bit easier, and use it in the rolling outerloop determinism tests