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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Compiler-rt missing long double builtins for x86_64"
href="https://bugs.llvm.org/show_bug.cgi?id=39376">39376</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Compiler-rt missing long double builtins for x86_64
</td>
</tr>
<tr>
<th>Product</th>
<td>compiler-rt
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>builtins
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>manojgupta@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Chrome OS bug: <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=843822">https://bugs.chromium.org/p/chromium/issues/detail?id=843822</a>
With glibc 2.27, clang cannot compile a static binary with compiler-rt since
compiler-rt does not have support for long double builtins for x86_64.
With glibc 2.27
cat a.c
#include "stdio.h"
int main() {
printf("hello.\n");
}
clang -static a.c -rtlib=compiler-rt
/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.x/../../../../lib64/libc.a(printf_fp.o):
In function `__printf_fp_l':
(.text+0x5ea): undefined reference to `__unordtf2'
/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.x/../../../../lib64/libc.a(printf_fphex.o):
In function `__printf_fphex':
(.text+0x9a): undefined reference to `__unordtf2'
The following patch is enough to add the builtins to compiler-rt but not sure
of the correctness or any other implications. Interesting thing to note is that
__LDBL_MANT_DIG__ is 64 so the check __LDBL_MANT_DIG__ == 113 failed on
x86_64/Linux.
diff --git a/lib/builtins/CMakeLists.txt b/lib/builtins/CMakeLists.txt
index 82332967b..c49d9af00 100644
--- a/lib/builtins/CMakeLists.txt
+++ b/lib/builtins/CMakeLists.txt
@@ -232,6 +232,7 @@ set(x86_ARCH_SOURCES
if (NOT MSVC)
set(x86_64_SOURCES
+ ${GENERIC_TF_SOURCES}
x86_64/floatdidf.c
x86_64/floatdisf.c
x86_64/floatdixf.c
diff --git a/lib/builtins/fp_lib.h b/lib/builtins/fp_lib.h
index a0e19ab6a..c4f9d1d90 100644
--- a/lib/builtins/fp_lib.h
+++ b/lib/builtins/fp_lib.h
@@ -103,7 +103,7 @@ static __inline void wideMultiply(rep_t a, rep_t b, rep_t
*hi, rep_t *lo) {
COMPILER_RT_ABI fp_t __adddf3(fp_t a, fp_t b);
#elif defined QUAD_PRECISION
-#if __LDBL_MANT_DIG__ == 113
+#ifdef __LP64__
#define CRT_LDBL_128BIT
typedef __uint128_t rep_t;
typedef __int128_t srep_t;</pre>
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