[Bug c/89436] New: [8/9 Regression] ICE in glibc/sysdeps/ieee754/dbl-64/e_pow.c (internal compiler error: in decompose, at rtl.h:2266)

[przemyslaw.wirkus at arm dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89436

            Bug ID: 89436
           Summary: [8/9 Regression] ICE in
                    glibc/sysdeps/ieee754/dbl-64/e_pow.c (internal
                    compiler error: in decompose, at rtl.h:2266)
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: przemyslaw.wirkus at arm dot com
  Target Milestone: ---

# GCC Version
    revision r268990

# Host system type
    Linux machine 4.15.0-43-generic #46-Ubuntu SMP Thu Dec 6 14:45:28 UTC 2018
x86_64 x86_64 x86_64 GNU/Linux
    Ubuntu 18.04.2 LTS

# Options given when GCC was configured/built (gcc2 stage)
    --target=arm-none-linux-gnueabi \
    --enable-shared \
    --disable-libatomic \
    --without-cloog \
    --without-isl \
    --disable-libssp \
    --disable-libgomp \
    --disable-libmudflap \
    --disable-libquadmath \
    --enable-checking=yes \
    --enable-languages=c  \
    --with-float=softfp \
    --with-fpu=crypto-neon-fp-armv8 \
    --with-mode=thumb \
    --with-arch=armv8-a \
    --with-arch=armv7-a

# Reduced testcase and command line that triggers the bug

$cat e_pow_cpp.c
typedef double a;
b;
c() {
  a d, e;
  b = d + d * e;
}

$ ./arm-none-linux-gnueabi-gcc -O2 -g e_pow_cpp.c -S -w -march=armv8-a
-mfloat-abi=softfp -mfpu=crypto-neon-fp-armv8
e_pow_cpp.c:2:1: warning: data definition has no type or storage class
    2 | b;
      | ^
e_pow_cpp.c:2:1: warning: type defaults to ‘int’ in declaration of ‘b’
[-Wimplicit-int]
e_pow_cpp.c:3:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
    3 | c() {
      | ^
e_pow_cpp.c: In function ‘c’:
e_pow_cpp.c:6:1: error: qsort comparator non-negative on sorted output: 0
    6 | }
      | ^
during RTL pass: cprop_hardreg
e_pow_cpp.c:6:1: internal compiler error: qsort checking failed
0x5a3764 qsort_chk_error
        $src/gcc/gcc/vec.c:214
0x14f0b09 qsort_chk(void*, unsigned long, unsigned long, int (*)(void const*,
void const*))
        $src/gcc/gcc/vec.c:257
0x151d1b1 gcc_qsort(void*, unsigned long, unsigned long, int (*)(void const*,
void const*))
        $src/gcc/gcc/sort.cc:238
0x7a6fa8 vec<df_mw_hardreg*, va_heap, vl_embed>::qsort(int (*)(void const*,
void const*))
        $src/gcc/gcc/vec.h:1114
0x7a6fa8 vec<df_mw_hardreg*, va_heap, vl_ptr>::qsort(int (*)(void const*, void
const*))
        $src/gcc/gcc/vec.h:1898
0x7a6fa8 df_sort_and_compress_mws
        $src/gcc/gcc/df-scan.c:2252
0x7a6fa8 df_canonize_collection_rec
        $src/gcc/gcc/df-scan.c:2281
0x7a932f df_insn_refs_collect
        $src/gcc/gcc/df-scan.c:3229
0x7a973a df_insn_refs_verify
        $src/gcc/gcc/df-scan.c:4088
0x7ab403 df_insn_rescan(rtx_insn*)
        $src/gcc/gcc/df-scan.c:1065
0xb44897 confirm_change_group()
        $src/gcc/gcc/recog.c:503
0xb47c1c apply_change_group()
        $src/gcc/gcc/recog.c:516
0xb4bbc8 copyprop_hardreg_forward_1
        $src/gcc/gcc/regcprop.c:1001
0xb4bfb9 execute
        $src/gcc/gcc/regcprop.c:1307
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