From 4dbc3b0478a01302cd8f62cc914e99a36f4e8efd Mon Sep 17 00:00:00 2001 From: Raymond Lu Date: Fri, 12 Aug 2011 10:12:13 -0500 Subject: [PATCH] [svn-r21221] The original code 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. But I tested the same change for the trunk with h5committest. --- test/dsets.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/test/dsets.c b/test/dsets.c index 902048b2e2..09256f4367 100644 --- a/test/dsets.c +++ b/test/dsets.c @@ -3677,7 +3677,18 @@ 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]);