RFR(S): 8063086: Math.pow yields different results upon repeated calls

[Roland Westrelin]

When trying to push this through jprt I had an assert failure due to an unreachable address. Here is a new webrev:

http://cr.openjdk.java.net/~roland/8063086/webrev.01/

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);

Roland.

> 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.
> 
> Roland.
> 
>> 
>> Thanks,
>> Vladimir
>> 
>> On 1/5/15 8:38 AM, Roland Westrelin wrote:
>>> http://cr.openjdk.java.net/~roland/8063086/webrev.00/
>>> 
>>> 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.
>>> 
>>> Roland.
>>> 
>