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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - mathlib call to fma is not inlined with -ffast-math"
href="https://bugs.llvm.org/show_bug.cgi?id=46172">46172</a>
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<th>Summary</th>
<td>mathlib call to fma is not inlined with -ffast-math
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Scalar Optimizations
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>spatel+llvm@rotateright.com
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</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>I'm not sure if this is an IR or codegen bug:
#include <math.h>
double fastfma(double x, double y, double z) {
return fma(x, y, z);
}
---------------------------------------------------------------------------
$ clang -O2 stdfma.c -S -o - -ffast-math -emit-llvm
define double @fastfma(double %x, double %y, double %z) {
%r = tail call fast double @llvm.fma.f64(double %x, double %y, double %z)
ret double %r
}
declare double @llvm.fma.f64(double, double, double) #1
---------------------------------------------------------------------------
$ ./llc -o - stdfma.ll
_fastfma:
jmp _fma
---------------------------------------------------------------------------
I was expecting to avoid the libm call with (some subset of) -ffast-math.</pre>
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