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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Disabling fp-contraction doesn't work. [#pragma clang fp contract(off)]"
href="https://bugs.llvm.org/show_bug.cgi?id=39679">39679</a>
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<th>Summary</th>
<td>Disabling fp-contraction doesn't work. [#pragma clang fp contract(off)]
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>trunk
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>guille@berkeley.edu
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>Trying to prevent contracting (*,+) into an FMA operation (to guarantee
cross_product(a, a) == 0).
I add '#pragma clang fp contract(off)' to the start of a block, compiler
accepts the pragma, but still generates an FMA instruction.
Example at: godbolt.org/z/Cg8rYi
Thanks.</pre>
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