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[svn-r21220] The original code

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i_mask = ~((unsigned)~0 << (precision[0] + offset[0])) & ((unsigned)~0 << offset[0]);
in line 3680 left shifted a 32-bit integer for 32-bit.  The result is undefined by C language.  A user
discovered it using clang compiler with -fcatch-undefined-behavior option (see Issue 7674
in Jira).  So I changed it in a funny way to avoid it.

Tested on jam, koala, and heiwa.
This commit is contained in:
Raymond Lu 2011-08-12 09:38:30 -05:00
parent 14f8f4d437
commit f32d49916d
1 changed files with 12 additions and 1 deletions
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13
test/dsets.c
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@ -3664,7 +3664,18 @@ test_nbit_compound_2(hid_t file)
/* Check that the values read are the same as the values written
* Use mask for checking the significant bits, ignoring the padding bits
*/
i_mask = ~((unsigned)~0 << (precision[0] + offset[0])) & ((unsigned)~0 << offset[0]);
/* The original code
* i_mask = ~((unsigned)~0 << (precision[0] + offset[0])) & ((unsigned)~0 << offset[0]);
* left shift a 32-bit integer for 32-bit. The result is undefined by C language. A user
* discovered it using clang compiler with -fcatch-undefined-behavior option (see Issue 7674
* in Jira). So I changed it in a funny way as below to avoid it. SLU - 2011/8/11
*/
if(sizeof(unsigned) > 4)
i_mask = ~((unsigned)~0 << (precision[0] + offset[0])) & ((unsigned)~0 << offset[0]);
else {
i_mask = 0xffffffff;
i_mask = i_mask & ((unsigned)~0 << offset[0]);
}
c_mask = ~((unsigned)~0 << (precision[1] + offset[1])) & ((unsigned)~0 << offset[1]);
s_mask = ~((unsigned)~0 << (precision[2] + offset[2])) & ((unsigned)~0 << offset[2]);
b_mask = ~((unsigned)~0 << (precision[4] + offset[4])) & ((unsigned)~0 << offset[4]);