https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69909
Bug ID: 69909
Summary: [6 Regression] wrong code with -Os and vectors @
x86_64
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: zsojka at seznam dot cz
Target Milestone: ---
Target: x86_64-pc-linux-gnu
Created attachment 37762
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37762&action=edit
reduced testcase
Output:
$ x86_64-pc-linux-gnu-gcc -Os testcase.c
$ ./a.out
0000000000000000000000000000002a
Aborted
$ ./a.out
ffff80c3ff7fffffffff8007fe00001a
Aborted
Stack is used uninitialised.
The assembly shows:
...
foo:
...
sub r11, QWORD PTR [rsp-64] # _33,
mov DWORD PTR [rsp+104], eax # v32u32_1, _3
sbb r12, QWORD PTR [rsp-56] # _33,
...
values at [rsp-64] and [rsp-56] are never initialised.
5-branch initialises them correctly.
$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-233588-checking-yes-rtl-df-nographite/bin/../libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-checking=yes,rtl,df --without-cloog --without-ppl --without-isl
--disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-233588-checking-yes-rtl-df-nographite
Thread model: posix
gcc version 6.0.0 20160220 (experimental) (GCC)
Tested revisions:
trunk r233588 - FAIL
5-branch r233581 - OK
4_9-branch r233576 - OK
