RFR(S): 8063086: Math.pow yields different results upon repeated calls
vladimir.kozlov at oracle.com
Thu Jan 8 16:58:51 UTC 2015
On 1/8/15 1:26 AM, Roland Westrelin wrote:
> When trying to push this through jprt I had an assert failure due to an unreachable address. Here is a new webrev:
> with the following change:
> --- a/src/cpu/x86/vm/macroAssembler_x86.cpp
> +++ b/src/cpu/x86/vm/macroAssembler_x86.cpp
> @@ -3189,7 +3189,9 @@
> static double two = 2.0;
> ExternalAddress two_addr((address)&two);
> - fld_d(two_addr); // Stack: 2 X Y
> + // constant maybe too far on 64 bit
> + lea(tmp2, two_addr);
> + fld_d(Address(tmp2, 0)); // Stack: 2 X Y
> fcmp(tmp, 2, true, false); // Stack: X Y
> jcc(Assembler::parity, y_not_2);
> jcc(Assembler::notEqual, y_not_2);
>> On Jan 7, 2015, at 2:20 PM, Roland Westrelin <roland.westrelin at oracle.com> wrote:
>>> Looks good. Make sure to run new test with -Xcomp and -XX:-TieredCompilation and Client VM.
>> Thanks for the review. I checked the test runs fine in these cases.
>>> On 1/5/15 8:38 AM, Roland Westrelin wrote:
>>>> With 8029302, C2 computes x^2 as x*x. The interpreter and C1 code don’t have the special case code and as a result an application can see different result for the same computation whether it’s executed by the interpreter/c1 or c2. Fixed by adding the special case to the interpreter and C1.
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