JDK-8138651 : -XX:DisableIntrinsic matches intrinsics overly eagerly
- Type: Bug
- Component: hotspot
- Sub-Component: compiler
- Affected Version: 9
- Priority: P3
- Status: Resolved
- Resolution: Fixed
- Submitted: 2015-09-30
- Updated: 2015-11-20
- Resolved: 2015-10-29
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| JDK 9 |
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9 b92Fixed  |
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Description
DisableIntrinsic filtering code looks for the vmIntrinsic name in the comma-separated list:
ccstr disable_intr = NULL;
if ((DisableIntrinsic[0] != '\0' && strstr(DisableIntrinsic, vmIntrinsics::name_at(id)) != NULL) ||
(!compilation_context.is_null() &&
CompilerOracle::has_option_value(compilation_context, "DisableIntrinsic", disable_intr) &&
strstr(disable_intr, vmIntrinsics::name_at(id)) != NULL)
) {
tty->print_cr("Disabling intrinsic %s by DisableIntrinsic", vmIntrinsics::name_at(id));
return true;
}
Which means that supplying -XX:DisableIntrinsic=_copyOfRange matches *both* _copyOf and _copyOfRange intrinsics. I think the code should actually look for the vmIntrinsic name to be followed with a comma or \0. It gets much worse when you are trying to disable some new intrinsic, e.g. _getCharStringU, and (Unsafe::)_getChar gets disabled along.
Makes performance work more tedious than it should nominally be.
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