[Bug tree-optimization/61917] New: ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[Bug tree-optimization/61917] New: ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

            Bug ID: 61917
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu in
                    vectorizable_reduction, at tree-vect-loop.c:4913
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The following code causes an ICE when compiled with the current gcc trunk and
gcc 4.9 at -O3 on x86_64-linux-gnu (in both 32-bit and 64-bit modes).

It is a regression from 4.8.x.

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.10.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure --prefix=/usr/local/gcc-trunk
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 4.10.0 20140725 (experimental) [trunk revision 213036] (GCC) 
$ 
$ gcc-trunk -O2 -c small.c
$ gcc-4.8 -O3 -c small.c
$ 
$ gcc-trunk -O3 -c small.c
small.c: In function ‘fn1’:
small.c:4:1: internal compiler error: in vectorizable_reduction, at
tree-vect-loop.c:4913
 fn1 ()
 ^
0xb8eb3c vectorizable_reduction(gimple_statement_base*, gimple_stmt_iterator*,
gimple_statement_base**, _slp_tree*)
    ../../gcc-trunk/gcc/tree-vect-loop.c:4913
0xb8144f vect_analyze_stmt(gimple_statement_base*, bool*, _slp_tree*)
    ../../gcc-trunk/gcc/tree-vect-stmts.c:7103
0xb8ccee vect_analyze_loop_operations
    ../../gcc-trunk/gcc/tree-vect-loop.c:1505
0xb8ccee vect_analyze_loop_2
    ../../gcc-trunk/gcc/tree-vect-loop.c:1766
0xb8ccee vect_analyze_loop(loop*)
    ../../gcc-trunk/gcc/tree-vect-loop.c:1864
0xba50cf vectorize_loops()
    ../../gcc-trunk/gcc/tree-vectorizer.c:432
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 
$ gcc-4.9 -O3 -c small.c
small.c: In function ‘fn1’:
small.c:4:1: internal compiler error: in vectorizable_reduction, at
tree-vect-loop.c:4907
 fn1 ()
 ^
0x9b6f35 vectorizable_reduction(gimple_statement_base*, gimple_stmt_iterator*,
gimple_statement_base**, _slp_tree*)
    ../../gcc-4.9.0/gcc/tree-vect-loop.c:4907
0x9a94e8 vect_analyze_stmt(gimple_statement_base*, bool*, _slp_tree*)
    ../../gcc-4.9.0/gcc/tree-vect-stmts.c:7103
0x9b54e6 vect_analyze_loop_operations
    ../../gcc-4.9.0/gcc/tree-vect-loop.c:1505
0x9b54e6 vect_analyze_loop_2
    ../../gcc-4.9.0/gcc/tree-vect-loop.c:1765
0x9b54e6 vect_analyze_loop(loop*)
    ../../gcc-4.9.0/gcc/tree-vect-loop.c:1863
0x9c9f3b vectorize_loops()
    ../../gcc-4.9.0/gcc/tree-vectorizer.c:430
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 


----------------------------


int a, b, c, d;

int
fn1 ()
{
  for (; c; c++)
    for (b = 0; b < 2; b++)
      d = a - d;
  return d; 
}
>From gcc-bugs-return-457127-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Sat Jul 26 05:40:23 2014
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From: "mitya57 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug preprocessor/61918] New: With -isystem, symlinks are sometimes processed incorrectly
Date: Sat, 26 Jul 2014 05:40:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida918

            Bug ID: 61918
           Summary: With -isystem, symlinks are sometimes processed
                    incorrectly
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mitya57 at gmail dot com

Originally reported at
https://bugs.debian.org/cgi-bin/bugreport.cgi?bugu5767.

Here is the minimal test case:

$ ls -l correct
lrwxrwxrwx 1 dmitry dmitry 16 Jul 26 09:07 first.h -> ../wrong/first.h
-rw-r--r-- 1 dmitry dmitry  0 Jul 26 09:27 second.h
$ ls -l wrong
-rw-r--r-- 1 dmitry dmitry 20 Jul 26 09:07 first.h
-rw-r--r-- 1 dmitry dmitry 38 Jul 26 09:27 second.h
$ cat wrong/first.h
#include "second.h"
$ cat wrong/second.h
#warning Should not include this file
$ cat correct/second.h
$ cat test.c
#include "first.h"
$ cpp -I $(pwd)/correct test.c >/dev/null
$ cpp -isystem $(pwd)/correct test.c >/dev/null
In file included from /tmp/wrong/first.h:1:0,
                 from test.c:1:
/tmp/wrong/second.h:1:2: warning: #warning Should not include this file [-Wcpp]
 #warning Should not include this file
  ^
$ cpp -isystem ./correct test.c >/dev/null
$

As you can see, correct/first.h is a symlink to wrong/first.h, which in turn
includes second.h. However, I see no reason why cpp follows that symlinks and
opens second.h in wrong directory.

When I use -I instead of -isystem, or use relative file path instead of
absolute, the behavior is correct. Also, clang always handles this correctly.

[Bug tree-optimization/61917] [4.9/5.0 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-07-27
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |4.9.2
            Summary|ICE on valid code at -O3 on |[4.9/5.0 Regression] ICE on
                   |x86_64-linux-gnu in         |valid code at -O3 on
                   |vectorizable_reduction, at  |x86_64-linux-gnu in
                   |tree-vect-loop.c:4913       |vectorizable_reduction, at
                   |                            |tree-vect-loop.c:4913
     Ever confirmed|0                           |1

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r203625.

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.9.2                       |4.9.3

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.2 has been released.

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
                 CC|                            |congh at google dot com

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[tarasevich at cs dot uni-saarland.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Andrey Tarasevich <tarasevich at cs dot uni-saarland.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tarasevich at cs dot uni-saarland.
                   |                            |de

--- Comment #3 from Andrey Tarasevich <tarasevich at cs dot uni-saarland.de> ---
Is it the same bug? It is triggered only if printf() is called. 


→ /home/tarasevich/build/bin/gcc492 -v -save-temps -O3 test_case_3001.c 
Using built-in specs.
COLLECT_GCC=/home/tarasevich/build/bin/gcc492
COLLECT_LTO_WRAPPER=/home/tarasevich/build/libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../../source/gcc_492/configure --enable-coverage
--prefix=/home/tarasevich/build/ --program-suffix=492 --disable-multilib
Thread model: posix
gcc version 4.9.2 (GCC) 
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-O3' '-mtune=generic' '-march=x86-64'
 /home/tarasevich/build/libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/cc1 -E
-quiet -v -imultiarch x86_64-linux-gnu test_case_3001.c -mtune=generic
-march=x86-64 -O3 -fpch-preprocess -o test_case_3001.i
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/home/tarasevich/build/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /home/tarasevich/build/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/include
 /usr/local/include
 /home/tarasevich/build/include
 /home/tarasevich/build/lib/gcc/x86_64-unknown-linux-gnu/4.9.2/include-fixed
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-O3' '-mtune=generic' '-march=x86-64'
 /home/tarasevich/build/libexec/gcc/x86_64-unknown-linux-gnu/4.9.2/cc1
-fpreprocessed test_case_3001.i -quiet -dumpbase test_case_3001.c
-mtune=generic -march=x86-64 -auxbase test_case_3001 -O3 -version -o
test_case_3001.s
GNU C (GCC) version 4.9.2 (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.9.2, GMP version 4.3.2, MPFR version 2.4.2, MPC
version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C (GCC) version 4.9.2 (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.9.2, GMP version 4.3.2, MPFR version 2.4.2, MPC
version 0.8.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: fc102f9fe8436bee9826789629a3ba6f
test_case_3001.c: In function ‘main’:
test_case_3001.c:10:5: warning: incompatible implicit declaration of built-in
function ‘printf’
     printf("%d", var4);
     ^
test_case_3001.c:1:5: internal compiler error: in vectorizable_reduction, at
tree-vect-loop.c:4913
 int main() {
     ^
0x118d0c2 vectorizable_reduction(gimple_statement_base*, gimple_stmt_iterator*,
gimple_statement_base**, _slp_tree*)
    ../../../source/gcc_492/gcc/tree-vect-loop.c:4913
0x116e79d vect_analyze_stmt(gimple_statement_base*, bool*, _slp_tree*)
    ../../../source/gcc_492/gcc/tree-vect-stmts.c:7106
0x117e50d vect_analyze_loop_operations
    ../../../source/gcc_492/gcc/tree-vect-loop.c:1505
0x117f5a3 vect_analyze_loop_2
    ../../../source/gcc_492/gcc/tree-vect-loop.c:1766
0x117fdd3 vect_analyze_loop(loop*)
    ../../../source/gcc_492/gcc/tree-vect-loop.c:1864
0x11b536c vectorize_loops()
    ../../../source/gcc_492/gcc/tree-vectorizer.c:430
0x102fb8d tree_loop_vectorize
    ../../../source/gcc_492/gcc/tree-ssa-loop.c:154
0x102fcc4 execute
    ../../../source/gcc_492/gcc/tree-ssa-loop.c:189
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.


-------------------------------

int main() {
    int var4 = 1;
    int var5 = -10;
    for (; var5 <= 0; ++var5) {
        int var6 = -1979310964;
        for (; var6 <= -1979310946; ++var6) {
            var4 = var5 - var4;
        }
    }
    printf("%d", var4);
}
>From gcc-bugs-return-470270-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Thu Dec 11 13:38:28 2014
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From: "mpolacek at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913
Date: Thu, 11 Dec 2014 13:38:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ida917

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Yes, I think that is the same bug.

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ktietz at gcc dot gnu.org

--- Comment #5 from Kai Tietz <ktietz at gcc dot gnu.org> ---
It is the same bug.  All is related to the issue that 'dt' might become
'vect_internal_def' with 'orig_stmt' being NULL.
By extending the assert at line 4993 as 'gcc_assert (orig_stmt || dt ==
vect_internal_def);' solves the issue for me for both provided samples.

Index: tree-vect-loop.c
===================================================================
--- tree-vect-loop.c    (Revision 220748)
+++ tree-vect-loop.c    (Arbeitskopie)
@@ -4990,7 +4990,7 @@ vectorizable_reduction (gimple stmt, gimple_stmt_i
       /* For pattern recognized stmts, orig_stmt might be a reduction,
         but some helper statements for the pattern might not, or
         might be COND_EXPRs with reduction uses in the condition.  */
-      gcc_assert (orig_stmt);
+      gcc_assert (orig_stmt || dt == vect_internal_def);
       return false;
     }
   if (!found_nested_cycle_def)

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #6 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Author: ktietz
Date: Wed Feb 25 13:36:00 2015
New Revision: 220966

URL: https://gcc.gnu.org/viewcvs?rev=220966&root=gcc&view=rev
Log:
2015-02-25  Richard Biener  <rguenther@suse.de>
    Kai Tietz  <ktietz@redhat.com>

    PR tree-optimization/61917
    * tree-vect-loop.c (vectorizable_reduction): Allow
    vect_internal_def without reduction to exit graceful.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-vect-loop.c

[Bug tree-optimization/61917] [4.9/5 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #7 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Author: ktietz
Date: Wed Feb 25 13:42:12 2015
New Revision: 220967

URL: https://gcc.gnu.org/viewcvs?rev=220967&root=gcc&view=rev
Log:
    PR tree-optimization/61917
    * gcc.dg/vect/vect-pr61917.c: New file.


Added:
    trunk/gcc/testsuite/gcc.dg/vect/vect-pr61917.c
Modified:
    trunk/gcc/testsuite/ChangeLog

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at redhat dot com
            Summary|[4.9/5 Regression] ICE on   |[4.9 Regression] ICE on
                   |valid code at -O3 on        |valid code at -O3 on
                   |x86_64-linux-gnu in         |x86_64-linux-gnu in
                   |vectorizable_reduction, at  |vectorizable_reduction, at
                   |tree-vect-loop.c:4913       |tree-vect-loop.c:4913

--- Comment #8 from Jeffrey A. Law <law at redhat dot com> ---
Fixed on trunk.

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #9 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Author: ktietz
Date: Wed Feb 25 14:12:46 2015
New Revision: 220968

URL: https://gcc.gnu.org/viewcvs?rev=220968&root=gcc&view=rev
Log:

2015-02-25  Richard Biener  <rguenther@suse.de>
    Kai Tietz  <ktietz@redhat.com>

    Backport from mainline
    PR tree-optimization/61917
    * tree-vect-loop.c (vectorizable_reduction): Allow
    vect_internal_def without reduction to exit graceful.

ChangeLog testsuite/

2015-02-25  Kai Tietz  <ktietz@redhat.com>

    Backport from mainline
    PR tree-optimization/61917
    * gcc.dg/vect/vect-pr61917.c: New file.


Added:
    branches/gcc-4_9-branch/gcc/testsuite/gcc.dg/vect/vect-pr61917.c
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_9-branch/gcc/tree-vect-loop.c

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

Kai Tietz <ktietz at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #10 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Fixed on trunk and 4.9

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #12 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Hmm, just retested it for gcc's trunk.  Can't reproduce it.  I will retest with
current trunk, I might have a different patch in tree, which makes the
difference here.
Additionally, what target you are using?

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #13 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Kai Tietz from comment #12)
> Hmm, just retested it for gcc's trunk.  Can't reproduce it.  I will retest
> with current trunk, I might have a different patch in tree, which makes the
> difference here.
> Additionally, what target you are using?

Also happened on 4.9 branch:

[hjl@gnu-6 gcc]$ ./xgcc -v
Using built-in specs.
COLLECT_GCC=./xgcc
Target: x86_64-unknown-linux-gnu
Configured with: /export/gnu/import/git/sources/gcc/configure
--enable-languages=c,c++ --disable-bootstrap --prefix=/usr/gcc-5.0.0
--with-local-prefix=/usr/local --enable-gnu-indirect-function --with-fpmath=sse
Thread model: posix
gcc version 5.0.0 20150225 (experimental) (GCC) 
[hjl@gnu-6 gcc]$

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #14 from Kai Tietz <ktietz at gcc dot gnu.org> ---
(In reply to H.J. Lu from comment #13)
> (In reply to Kai Tietz from comment #12)
> > Hmm, just retested it for gcc's trunk.  Can't reproduce it.  I will retest
> > with current trunk, I might have a different patch in tree, which makes the
> > difference here.
> > Additionally, what target you are using?
> 
> Also happened on 4.9 branch:

So for me it doesn't happen on trunk, so the "Also" seems to me something
special for you.  I will recheck 4.9, as here we might have a regression I
didn't caught ...

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #15 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Kai Tietz from comment #14)
> (In reply to H.J. Lu from comment #13)
> > (In reply to Kai Tietz from comment #12)
> > > Hmm, just retested it for gcc's trunk.  Can't reproduce it.  I will retest
> > > with current trunk, I might have a different patch in tree, which makes the
> > > difference here.
> > > Additionally, what target you are using?
> > 
> > Also happened on 4.9 branch:
> 
> So for me it doesn't happen on trunk, so the "Also" seems to me something
> special for you.  I will recheck 4.9, as here we might have a regression I
> didn't caught ...

I don't know why you didn't see it:

Starting program: /export/build/gnu/gcc-4.9/build-x86_64-linux/gcc/cc1
-fpreprocessed /tmp/x.i -quiet -dumpbase x.i -mtune=generic -march=x86-64
-auxbase x -O -version -ftree-vectorize -o x.i
GNU C (GCC) version 4.9.3 20150225 (prerelease) (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.8.3 20140911 (Red Hat 4.8.3-7), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C (GCC) version 4.9.3 20150225 (prerelease) (x86_64-unknown-linux-gnu)
    compiled by GNU C version 4.8.3 20140911 (Red Hat 4.8.3-7), GMP version
5.1.2, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: e64a271cb64a39ff067a5fd30c57a8d9

Program received signal SIGSEGV, Segmentation fault.
0x0000000000c1efa1 in gimple_code (g=0x0)
    at /export/gnu/import/git/gcc-release/gcc/gimple.h:1406
1406      return g->code;
(gdb) bt
#0  0x0000000000c1efa1 in gimple_code (g=0x0)
    at /export/gnu/import/git/gcc-release/gcc/gimple.h:1406
#1  0x0000000000c2bc5d in vectorizable_reduction (
    stmt=<gimple_assign 0x7ffff19e0000>, gsi=0x0, vec_stmt=0x0, slp_node=0x0)
    at /export/gnu/import/git/gcc-release/gcc/tree-vect-loop.c:4915
#2  0x0000000000c1bcca in vect_analyze_stmt (
    stmt=<gimple_assign 0x7ffff19e0000>, need_to_vectorize=0x7fffffffd6af, 
    node=0x0) at /export/gnu/import/git/gcc-release/gcc/tree-vect-stmts.c:7107
#3  0x0000000000c1b723 in vect_analyze_stmt (
    stmt=<gimple_assign 0x7ffff19d32c0>, need_to_vectorize=0x7fffffffd6af, 
    node=0x0) at /export/gnu/import/git/gcc-release/gcc/tree-vect-stmts.c:7023
#4  0x0000000000c24048 in vect_analyze_loop_operations (loop_vinfo=0x1a75950, 
    slp=false) at /export/gnu/import/git/gcc-release/gcc/tree-vect-loop.c:1505
#5  0x0000000000c247ee in vect_analyze_loop_2 (loop_vinfo=0x1a75950)
    at /export/gnu/import/git/gcc-release/gcc/tree-vect-loop.c:1766
#6  0x0000000000c24b73 in vect_analyze_loop (loop=0x7ffff19d50a0)
    at /export/gnu/import/git/gcc-release/gcc/tree-vect-loop.c:1864
#7  0x0000000000c41516 in vectorize_loops ()
    at /export/gnu/import/git/gcc-release/gcc/tree-vectorizer.c:430
#8  0x0000000000b713d3 in tree_loop_vectorize ()
    at /export/gnu/import/git/gcc-release/gcc/tree-ssa-loop.c:154
#9  0x0000000000b7145d in (anonymous namespace)::pass_vectorize::execute (
    this=0x1a20150)
---Type <return> to continue, or q <return> to quit---
    at /export/gnu/import/git/gcc-release/gcc/tree-ssa-loop.c:189
#10 0x000000000095dde6 in execute_one_pass (
    pass=<opt_pass* 0x1a20150 "vect"(119)>)
    at /export/gnu/import/git/gcc-release/gcc/passes.c:2233
#11 0x000000000095dfff in execute_pass_list (
    pass=<opt_pass* 0x1a20150 "vect"(119)>)
    at /export/gnu/import/git/gcc-release/gcc/passes.c:2286
#12 0x000000000095e030 in execute_pass_list (
    pass=<opt_pass* 0x1a1fa30 "loop"(101)>)
    at /export/gnu/import/git/gcc-release/gcc/passes.c:2287
#13 0x000000000095e030 in execute_pass_list (
    pass=<opt_pass* 0x1a1e950 "*all_optimizations"(-1)>)
    at /export/gnu/import/git/gcc-release/gcc/passes.c:2287
#14 0x00000000006bb569 in expand_function (
    node=<cgraph_node* 0x7ffff18a9e18 "f">)
    at /export/gnu/import/git/gcc-release/gcc/cgraphunit.c:1774
#15 0x00000000006bb9ca in expand_all_functions ()
    at /export/gnu/import/git/gcc-release/gcc/cgraphunit.c:1908
#16 0x00000000006bc2ed in compile ()
    at /export/gnu/import/git/gcc-release/gcc/cgraphunit.c:2252
#17 0x00000000006bc3c8 in finalize_compilation_unit ()
    at /export/gnu/import/git/gcc-release/gcc/cgraphunit.c:2329
#18 0x00000000005817c7 in c_write_global_declarations ()
---Type <return> to continue, or q <return> to quit---q
 at /export/gnu/import/gQuit
(gdb) f 2
#2  0x0000000000c1bcca in vect_analyze_stmt (
    stmt=<gimple_assign 0x7ffff19e0000>, need_to_vectorize=0x7fffffffd6af, 
    node=0x0) at /export/gnu/import/git/gcc-release/gcc/tree-vect-stmts.c:7107
7107                || vectorizable_reduction (stmt, NULL, NULL, NULL)
(gdb) call debug_gimple_stmt (stmt)
patt_25 = a_lsm.8_11 < 0 ? 7 : 0;
(gdb) f 1
#1  0x0000000000c2bc5d in vectorizable_reduction (
    stmt=<gimple_assign 0x7ffff19e0000>, gsi=0x0, vec_stmt=0x0, slp_node=0x0)
    at /export/gnu/import/git/gcc-release/gcc/tree-vect-loop.c:4915
4915      if (gimple_code (reduc_def_stmt) != GIMPLE_PHI)
(gdb) p reduc_def_stmt
$2 = <gimple 0x0>
(gdb)

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #16 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I certainly can reproduce it, the problem is that reduc_def_stmt is NULL.
dt is vect_constant_def.

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #17 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Just posted a fix.  For the 4.9 branch I could finally reproduce this error. 
It is caused by the PHI-check for a vector-constant, which obviously has no
valid statment ...

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #18 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Author: ktietz
Date: Wed Feb 25 18:20:34 2015
New Revision: 220986

URL: https://gcc.gnu.org/viewcvs?rev=220986&root=gcc&view=rev
Log:
2015-02-25  Kai Tietz  <ktietz@redhat.com>

    PR tree-optimization/61917
    * tree-vect-loop.c (vectorizable_reduction): Handle obvious case
    that reduc_def_stmt is null.


Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/tree-vect-loop.c

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #19 from Kai Tietz <ktietz at gcc dot gnu.org> ---
Author: ktietz
Date: Wed Feb 25 18:21:37 2015
New Revision: 220987

URL: https://gcc.gnu.org/viewcvs?rev=220987&root=gcc&view=rev
Log:
    PR tree-optimization/61917
    * tree-vect-loop.c (vectorizable_reduction): Handle obvious case
    that reduc_def_stmt is null.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-vect-loop.c

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[ktietz at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

--- Comment #20 from Kai Tietz <ktietz at gcc dot gnu.org> ---
HJ: Does recent patch fixes issue for you too?

[Bug tree-optimization/61917] [4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu in vectorizable_reduction, at tree-vect-loop.c:4913

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61917

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #21 from H.J. Lu <hjl.tools at gmail dot com> ---
Fixed.