Possible C compiler bug

Possible C compiler bug

Hello everyone, the attached test program gives wrong results when compiled with -O1 using the compiler versions 12.1.1, 12.1.6, 13.1.3, or 14.0.1 while it produces the expected results with gcc 4.4.7. The code was distilled from a physics simulation that does a lot of matrix operations. In this test program, a pointer to a nested structure of doubles is passed to a function that modifies these doubles. It seems the wrong operands are used here.

Downloadtext/x-csrc bug-icc-su3proj.c2.68 KB
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For more complete information about compiler optimizations, see our Optimization Notice.

I've also reproduced this behaviour with 14.0.2. The problem in the test case only surfaces with -O1 (not with default optimization or higher), but the code authors tell me that the production code (which is not suitable as a test case) also produces wrong results with -O2 (fwiw).

Best wishes


Hi folks,
  Yes, this is a bug and I will file this issue with our developers and keep you updated. Appreciate your patience till then.
Kittur .

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