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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 - Longer compilation times"
href="https://bugs.llvm.org/show_bug.cgi?id=43855">43855</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Longer compilation times
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Common Code Generator Code
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>leonardchan@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>We noticed builds for zircon were taking longer than normal and were able to
trace the cause to
<a href="https://reviews.llvm.org/rGee50590e1684c197bc4336984795e48bf53c7a4e">https://reviews.llvm.org/rGee50590e1684c197bc4336984795e48bf53c7a4e</a>.
One of the files in our build in particular is taking almost 6x as long to
compile.
```
# clang revision ee50590e1684c197bc4336984795e48bf53c7a4e
$ time
~/llvm-monorepo/llvm-build-3-master-fuchsia-toolchain/install/bin/clang++ -o
user-x64-asan/obj/system/ulib/fbl/test/fbl-test.intrusive_doubly_linked_list_tests.cc.o
-DZX_DEBUGLEVEL=2 -D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1 -D_ALL_SOURCE
-DWITH_FRAME_POINTERS=1 -fno-common --target=x86_64-fuchsia -mcx16
-fcrash-diagnostics-dir=clang-crashreports -fcolor-diagnostics
-no-canonical-prefixes -O2 -g3 -Wall -Wextra -Wno-unused-parameter
-Werror=unused-label -Werror=return-type -Wno-address-of-packed-member
-Wnewline-eof -Wno-unknown-warning-option -Wno-c99-designator
-Wno-int-in-bool-context -ffunction-sections -fdata-sections -Wthread-safety
-fvisibility=hidden -ftrivial-auto-var-init=pattern -Werror
-Wno-error=deprecated-declarations -fno-omit-frame-pointer -fsanitize=address
-Wno-unused-function -std=c++17 -Wconversion -Wno-sign-conversion -Wextra-semi
-Wno-deprecated-copy -ftemplate-backtrace-limit=0 -fno-exceptions -fno-rtti
-fno-threadsafe-statics -fvisibility-inlines-hidden -c ~/misc/reproducer.cc
real 7m3.756s
user 7m1.799s
sys 0m1.959s
# clang revision b8042dbe2bbf129cb524fca7a48737e99d1e46bc (the commit before
ee50590e1684c197bc4336984795e48bf53c7a4e)
$ time ../../prebuilt/third_party/clang/linux-x64/bin/clang++ -o
user-x64-asan/obj/system/ulib/fbl/test/fbl-test.intrusive_doubly_linked_list_tests.cc.o
-DZX_DEBUGLEVEL=2 -D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1 -D_ALL_SOURCE
-DWITH_FRAME_POINTERS=1 -fno-common --target=x86_64-fuchsia -mcx16
-fcrash-diagnostics-dir=clang-crashreports -fcolor-diagnostics
-no-canonical-prefixes -O2 -g3 -Wall -Wextra -Wno-unused-parameter
-Werror=unused-label -Werror=return-type -Wno-address-of-packed-member
-Wnewline-eof -Wno-unknown-warning-option -Wno-c99-designator
-Wno-int-in-bool-context -ffunction-sections -fdata-sections -Wthread-safety
-fvisibility=hidden -ftrivial-auto-var-init=pattern -Werror
-Wno-error=deprecated-declarations -fno-omit-frame-pointer -fsanitize=address
-Wno-unused-function -std=c++17 -Wconversion -Wno-sign-conversion -Wextra-semi
-Wno-deprecated-copy -ftemplate-backtrace-limit=0 -fno-exceptions -fno-rtti
-fno-threadsafe-statics -fvisibility-inlines-hidden -c ~/misc/reproducer.cc
real 1m9.815s
user 1m8.764s
sys 0m1.055s
```
Reproducer attached. I can try to make the reducer smaller if it helps.</pre>
</div>
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