Bug of the Month

BYTEmarks Unearth Compiler Discrepancy

Sybase Waterloo (formerly known as Watcom) says it's investigating a possible bug in Watcom C/C++ version 11 that's related to integer-operation performance. BYTE discovered the performance discrepancy when recompiling version 2 of our BYTEmark Native Mode benchmarks.

Because the BYTEmark suite is written in ANSI C, the results you get from the benchmarks can vary from compiler to compiler if one compiler's optimizations are better than another's. Occasionally, BYTE will recompile the benchmarks to take advantage of a compiler's new performance optimizations. BYTE discovered a possible problem with Sybase's comp iler when recompiling the x86 version of the BYTEmark suite to take advantage of the performance improvements of Watcom C/C++ version 11, which was released earlier this year.

As you can see from the chart , the BYTEmark tests involving integer operations actually ran faster on a 166-MHz Pentium-based PC when compiled by Watcom version 10 than they did when recompiled using version 11 running on the same PC. Many of these tests, such as Numeric Sort, String Sort, Assignment Algorithm, and International Data Encryption Algorithm (IDEA), perform the same types of fundamental operations as do word processing, spreadsheet, and communications programs. (For more information about the BYTEmark suite, see page 74 of the March 1995 BYTE or http://www.byte.com/bmark/bdoc.htm .) Sybase says that it hopes to have a solution to this problem available by early this summer.

Send yours to 7644 3.1723@compuserve.com!

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Watcom 10: Faster Integer Performance

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BYTEmarks compiled with Watcom 10 run faster than with Watcom 11.