https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97386
Bug ID: 97386
Summary: [8/9/10/11 Regression] wrong code with
__builtin_bswap16() of rotated 64bit value
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zsojka at seznam dot cz
Target Milestone: ---
Created attachment 49353
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49353&action=edit
reduced testcase
Output:
$ x86_64-pc-linux-gnu-gcc -O testcase.c
$ ./a.out
Aborted
The code in fact rotates 0xcccc00 instead of 0xcccc.
foo:
mov rcx, QWORD PTR c[rip]
mov eax, 13421568 # 0xcccc00
rol rax, cl
ret
$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r11-3806-20201012001625-g2baa36d4911-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r11-3806-20201012001625-g2baa36d4911-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.0.0 20201012 (experimental) (GCC)
