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<body><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">On Monday, August 14, 2023 1:25:23 A.M. CDT Detlef Matthiessen wrote:</p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> Hi Steve,</p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> </p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> right after I replied to the bug report, I noticed:</p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> </p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> dm@fluke:/tmp$ diff test-no-sse4 test-sse4</p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> dm@fluke:/tmp$</p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> </p>
<p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">> Can you confirm that the attached binaries are identical?</p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">Nice catch. They are identical. I repeated the compilations this morning with/without -msse4.1 and the result is indeed identical. In fact, it is the same when I omit *both* -msse2 and -msse4.1.</p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">I notice also that nowhere does the code reference the matrix computed. I wondered whether all that code was being optimized away -- so I added code to reference it:</p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;"><span style="color:#000000;"><span style="background-color:#ffffff;"><span style="font-family:monospace;">std::cout << "Element[0][0] = " << yuv2rgb_bt601(0,0) << "\n";</span></span></span></p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">However, there is no change: the binary is identical regardless of the -m options. </p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">So I'm back to square 1, very confused by your crash.</p>
<br /><p style="margin-top:0;margin-bottom:0;margin-left:0;margin-right:0;">-Steve</p>
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