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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - __float128 can't be passed into an inline asm block's 'x' input"
href="https://bugs.llvm.org/show_bug.cgi?id=43157">43157</a>
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<th>Summary</th>
<td>__float128 can't be passed into an inline asm block's 'x' input
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<th>Product</th>
<td>libraries
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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
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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>Backend: X86
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>gbs@canishe.com
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<th>CC</th>
<td>craig.topper@gmail.com, llvm-bugs@lists.llvm.org, llvm-dev@redking.me.uk, spatel+llvm@rotateright.com
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<p>
<div>
<pre>The following code (adapted from glibc) compiles under gcc but not clang:
# define math_force_eval(x) \
do { \
if (sizeof (x) <= sizeof (double) \
|| __builtin_types_compatible_p (__typeof (x), __float128)) \
__asm __volatile ("" : : "x" (x)); \
else \
__asm __volatile ("" : : "f" (x)); \
} while (0)
void foo(__float128 x) {
__float128 bar = x * 1.5;
math_force_eval(bar); // <-- couldn't allocate input reg for constraint 'x'
}
The issue appears to be in X86TargetLowering::getRegForInlineAsmConstraint,
which has a switch statement covering many other number types and the comment
"TODO: Handle f128 and i128 in FR128RegClass after it is tested well."</pre>
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