RFR(S): 8179618: Fixes for range of OptoLoopAlignment and Inlining flags

[Thomas Stüfe]

Hi Goetz,

c2_globals.hpp:

-          range(0, max_intx)
 \
+          range(0, ((intx)MIN2((int64_t)max_intx,(int64_t)(+1.0e10))))
 \

32bit: I would have expected a build warning for the cast. Is it okay that
we can never reach the max value on 32bit?

You could probably loose some brackets (around +1.0e10 and around the whole
MIN2 expression).

commandLineFlagConstraintsCompiler.cpp:

     CommandLineError::print(verbose,
                             "OptoLoopAlignment (" INTX_FORMAT ") must be "
                             "multiple of NOP size\n");

There is an error here, the print parameter is missing. Would have expected
the compiler to complain, actually - at least the gcc. Again, curious.

Kind Regards, Thomas

On Thu, May 4, 2017 at 12:57 PM, Lindenmaier, Goetz <
goetz.lindenmaier at sap.com> wrote:

> Hi,
>
>
>
> This change fixes range handling of a few flags of C2.
>
> This should go to jdk10, and later be downported to some
>
> update of jdk9.
>
>
>
> Please review this change. I please need a sponsor.
>
> http://cr.openjdk.java.net/~goetz/wr17/8179618-FlagRanges/webrev.01/
>
>
>
> Class WarmCallInfo limits its values to 1.0e10, but the flags used
>
> to set it's fields (HotCallCountThreshold etc.) are limited by max_intx.
>
> Using values over 1.0e10 causes assertions in the debug build.
>
>
>
> OptoLoopAlignment must be a multiple of nop size, else it's not
>
> possible to generate the instructions that go into the pad.
>
> On x86 NOP size is 1, so it's no problem.
>
> For SPARC, OptoLoopAlignmentConstraintFunc implements a special
>
> case for bigger NOPs. This is also needed for s390 and ppc.
>
> I just removed the #define, as the code works also on platforms
>
> where NOPsize == 1. Actually, it should be optimized by the C
>
> compiler in these cases.
>
>
>
> Best regards,
>
>   Goetz.
>
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