[Bug tree-optimization/105368] New: [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[Bug tree-optimization/105368] New: [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

            Bug ID: 105368
           Summary: [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost
                    (tree-ssa-math-opts.cc:1441) with -Ofast and
                    __builtin_powf()
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu

Created attachment 52861
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=52861&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -Ofast testcase.c -wrapper valgrind,-q
==11132== Invalid read of size 1
==11132==    at 0x15381AE: powi_lookup_cost (tree-ssa-math-opts.cc:1441)
==11132==    by 0x15381AE: powi_cost(long) [clone .part.0]
(tree-ssa-math-opts.cc:1489)
==11132==    by 0x153EA67: powi_cost (tree-ssa-math-opts.cc:1461)
==11132==    by 0x153EA67: gimple_expand_builtin_pow(gimple_stmt_iterator*,
unsigned int, tree_node*, tree_node*) (tree-ssa-math-opts.cc:2048)
==11132==    by 0x153EDE9: (anonymous
namespace)::pass_cse_sincos::execute(function*) (tree-ssa-math-opts.cc:2317)
==11132==    by 0x1298129: execute_one_pass(opt_pass*) (passes.cc:2638)
==11132==    by 0x12989EF: execute_pass_list_1(opt_pass*) (passes.cc:2738)
==11132==    by 0x1298A01: execute_pass_list_1(opt_pass*) (passes.cc:2739)
==11132==    by 0x1298A28: execute_pass_list(function*, opt_pass*)
(passes.cc:2749)
==11132==    by 0xEBD785: expand (cgraphunit.cc:1835)
==11132==    by 0xEBD785: cgraph_node::expand() (cgraphunit.cc:1788)
==11132==    by 0xEBED1F: expand_all_functions (cgraphunit.cc:1999)
==11132==    by 0xEBED1F: symbol_table::compile() [clone .part.0]
(cgraphunit.cc:2349)
==11132==    by 0xEC1957: compile (cgraphunit.cc:2262)
==11132==    by 0xEC1957: symbol_table::finalize_compilation_unit()
(cgraphunit.cc:2530)
==11132==    by 0x13A405F: compile_file() (toplev.cc:479)
==11132==    by 0xD0523D: do_compile (toplev.cc:2168)
==11132==    by 0xD0523D: toplev::main(int, char**) (toplev.cc:2320)
==11132==  Address 0x8000001ffeffec10 is not stack'd, malloc'd or (recently)
free'd
==11132== 
during GIMPLE pass: sincos
testcase.c: In function 'foo':
testcase.c:6:1: internal compiler error: Segmentation fault
    6 | foo (short s, long l)
      | ^~~
0x13a3d9f crash_signal
        /repo/gcc-trunk/gcc/toplev.cc:322
0x15381ae powi_lookup_cost
        /repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:1441
0x15381ae powi_cost
        /repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:1489
0x153ea67 powi_cost
        /repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:1461
0x153ea67 gimple_expand_builtin_pow
        /repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:2048
0x153ede9 execute
        /repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:2317
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ 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-r12-8236-20220424133922-g6b7441a46c7-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.1/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
--disable-bootstrap --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-r12-8236-20220424133922-g6b7441a46c7-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.1 20220424 (experimental) (GCC)

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I can't reproduce but I also don't see how the code could crash there.

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #2 from Zdenek Sojka <zsojka at seznam dot cz> ---
(gdb) disas
Dump of assembler code for function powi_cost(long):
   0x0000000001538160 <+0>:       push   %r14
   0x0000000001538162 <+2>:       mov    $0x20,%ecx
   0x0000000001538167 <+7>:       push   %r13
   0x0000000001538169 <+9>:       push   %r12
   0x000000000153816b <+11>:      push   %rbp
   0x000000000153816c <+12>:      push   %rbx
   0x000000000153816d <+13>:      mov    %rdi,%rbx
   0x0000000001538170 <+16>:      sub    $0x100,%rsp
   0x0000000001538177 <+23>:      neg    %rbx
   0x000000000153817a <+26>:      cmovs  %rdi,%rbx
   0x000000000153817e <+30>:      mov    %rsp,%r13
   0x0000000001538181 <+33>:      xor    %eax,%eax
   0x0000000001538183 <+35>:      xor    %r12d,%r12d
   0x0000000001538186 <+38>:      mov    %r13,%rdi
   0x0000000001538189 <+41>:      rep stos %rax,%es:(%rdi)
   0x000000000153818c <+44>:      movb   $0x1,0x1(%rsp)
=> 0x0000000001538191 <+49>:      cmp    $0xff,%rbx
   0x0000000001538198 <+56>:      jg     0x15381b0 <powi_cost(long)+80>
   0x000000000153819a <+58>:      jmp    0x1538207 <powi_cost(long)+167>

1463    
1464      /* Ignore the reciprocal when calculating the cost.  */
1465      val = (n < 0) ? -n : n;
   0x000000000153816d <+13>:      mov    %rdi,%rbx

1454    powi_cost (HOST_WIDE_INT n)
   0x0000000001538170 <+16>:      sub    $0x100,%rsp

1455    {
1456      bool cache[POWI_TABLE_SIZE];
1457      unsigned HOST_WIDE_INT digit;
1458      unsigned HOST_WIDE_INT val;
1459      int result;
1460    
1461      if (n == 0)
1462        return 0;
--Type <RET> for more, q to quit, c to continue without paging--
1463    
1464      /* Ignore the reciprocal when calculating the cost.  */
1465      val = (n < 0) ? -n : n;
   0x0000000001538177 <+23>:      neg    %rbx
   0x000000000153817a <+26>:      cmovs  %rdi,%rbx

...

/repo/gcc-trunk/gcc/tree-ssa-math-opts.cc:
1469      cache[1] = true;
   0x000000000153818c <+44>:      movb   $0x1,0x1(%rsp)

1472    
1473      while (val >= POWI_TABLE_SIZE)
=> 0x0000000001538191 <+49>:      cmp    $0xff,%rbx
   0x0000000001538198 <+56>:      jg     0x15381b0 <powi_cost(long)+80>
   0x000000000153819a <+58>:      jmp    0x1538207 <powi_cost(long)+167>


(gdb) p/x n
$19 = 0x8000000000000000
(gdb) p/x val
$20 = 0x8000000000000000
(gdb) p/x $rbx
$22 = 0x8000000000000000

The "while (val >= POWI_TABLE_SIZE)" check seems to be done in signed
arithmetics ("jg" conditional jump), so the value is not reduced and cache[i]
accesses out of bounds.

This happens with both boostrapped and non-bootstrapped compiler (using host
gcc-11.3.0)

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #3 from Zdenek Sojka <zsojka at seznam dot cz> ---
I think the issue might be in the:

> 1463    
> 1464      /* Ignore the reciprocal when calculating the cost.  */
> 1465      val = (n < 0) ? -n : n;

expression, for the case n == LONG_MIN, but I am not a language lawyer. (-n is
not representable in the (promoted) signed type)

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-04-25
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Zdenek Sojka from comment #3)
> I think the issue might be in the:
> 
> > 1463    
> > 1464      /* Ignore the reciprocal when calculating the cost.  */
> > 1465      val = (n < 0) ? -n : n;
> 
> expression, for the case n == LONG_MIN, but I am not a language lawyer. (-n
> is not representable in the (promoted) signed type)

Ah, good point.

diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 102b7a2cc99..7555793948e 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -1462,7 +1462,7 @@ powi_cost (HOST_WIDE_INT n)
     return 0;

   /* Ignore the reciprocal when calculating the cost.  */
-  val = (n < 0) ? -n : n;
+  val = absu_hwi (n);

   /* Initialize the exponent cache.  */
   memset (cache, 0, POWI_TABLE_SIZE * sizeof (bool));


should fix that.

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Might be easier to reproduce using ubsan too.

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:f0e170f72f8bfaa2a64e1d09ebdfd48f917420f1

commit r12-8242-gf0e170f72f8bfaa2a64e1d09ebdfd48f917420f1
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Apr 25 10:55:21 2022 +0200

    tree-optimization/105368 - avoid overflow in powi_cost

    The following avoids undefined signed overflow when computing
    the absolute of the exponent in powi_cost.

    2022-04-25  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/105368
            * tree-ssa-math-opts.cc (powi_cost): Use absu_hwi.

[Bug tree-optimization/105368] [10/11/12 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #7 from Zdenek Sojka <zsojka at seznam dot cz> ---
I can confirm the patch fixes the testcase for me.

[Bug tree-optimization/105368] [10/11 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|12.0                        |
            Summary|[10/11/12 Regression] ICE:  |[10/11 Regression] ICE:
                   |SIGSEGV in powi_lookup_cost |SIGSEGV in powi_lookup_cost
                   |(tree-ssa-math-opts.cc:1441 |(tree-ssa-math-opts.cc:1441
                   |) with -Ofast and           |) with -Ofast and
                   |__builtin_powf()            |__builtin_powf()
      Known to work|                            |12.0

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Thanks.

[Bug tree-optimization/105368] [10/11 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
   Target Milestone|---                         |10.4

[Bug tree-optimization/105368] [10/11 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:3e6ae76385c60ad1ef63270ba969729a40ca1245

commit r11-10019-g3e6ae76385c60ad1ef63270ba969729a40ca1245
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Apr 25 10:55:21 2022 +0200

    tree-optimization/105368 - avoid overflow in powi_cost

    The following avoids undefined signed overflow when computing
    the absolute of the exponent in powi_cost.

    2022-04-25  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/105368
            * tree-ssa-math-opts.c (powi_cost): Use absu_hwi.

    (cherry picked from commit f0e170f72f8bfaa2a64e1d09ebdfd48f917420f1)

[Bug tree-optimization/105368] [10 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:ebe6ffee1aa2d819e4fbdf4130e054a33c274b38

commit r10-10764-gebe6ffee1aa2d819e4fbdf4130e054a33c274b38
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Apr 25 10:55:21 2022 +0200

    tree-optimization/105368 - avoid overflow in powi_cost

    The following avoids undefined signed overflow when computing
    the absolute of the exponent in powi_cost.

    2022-04-25  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/105368
            * tree-ssa-math-opts.c (powi_cost): Use absu_hwi.

    (cherry picked from commit f0e170f72f8bfaa2a64e1d09ebdfd48f917420f1)

[Bug tree-optimization/105368] [10 Regression] ICE: SIGSEGV in powi_lookup_cost (tree-ssa-math-opts.cc:1441) with -Ofast and __builtin_powf()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105368

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|                            |10.3.1
         Resolution|---                         |FIXED
      Known to fail|                            |10.3.0

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.