https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94451
Bug ID: 94451
Summary: April 1st 2020 GCC does not compile spec 2017 gcc_r
benchmark with -O3
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: meissner at gcc dot gnu.org
Target Milestone: ---
Created attachment 48166
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48166&action=edit
decimal64.i file that shows the bug.
I was building Spec 2017 with the current master compiler branch, and it failed
in 3 benchmarks.
I looked at the failure of the gcc_r benchmark, and I discovered that the
decimal64.c function gets a compiler error when I build a compiler with default
checks enabled. I narrowed it down so that it fails with -O2 -fsplit-loops
-ftree-vectorize and -fgnu89-inline (the -fgnu89-inline is not needed for the
failure, but it is generally needed to compile Spec 2017).
-perch-> /opt/at13.0/bin/gdb cc1
GNU gdb (GDB) 8.3.1.20191211-git
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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Type "show copying" and "show warranty" for details.
This GDB was configured as "powerpc64le-linux-gnu".
Type "show configuration" for configuration details.
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Reading symbols from cc1...
Breakpoint 1 at 0x101dba40: file /home/meissner/fsf-src/trunk/gcc/diagnostic.c,
line 1777.
Breakpoint 2 at 0x1193e368: file /home/meissner/fsf-src/trunk/gcc/diagnostic.c,
line 1706.
Breakpoint 3 at 0x11a15fe8
Breakpoint 4 at 0x11a15fc4
File tree.h will be skipped when stepping.
File is-a.h will be skipped when stepping.
File line-map.h will be skipped when stepping.
File timevar.h will be skipped when stepping.
Function rtx_expr_list::next will be skipped when stepping.
Function rtx_expr_list::element will be skipped when stepping.
Function rtx_insn_list::next will be skipped when stepping.
Function rtx_insn_list::insn will be skipped when stepping.
Function rtx_sequence::len will be skipped when stepping.
Function rtx_sequence::element will be skipped when stepping.
Function rtx_sequence::insn will be skipped when stepping.
Function INSN_UID will be skipped when stepping.
Function PREV_INSN will be skipped when stepping.
Function SET_PREV_INSN will be skipped when stepping.
Function NEXT_INSN will be skipped when stepping.
Function SET_NEXT_INSN will be skipped when stepping.
Function BLOCK_FOR_INSN will be skipped when stepping.
Function PATTERN will be skipped when stepping.
Function INSN_LOCATION will be skipped when stepping.
Function INSN_HAS_LOCATION will be skipped when stepping.
Function JUMP_LABEL_AS_INSN will be skipped when stepping.
Successfully loaded GDB hooks for GCC
(gdb) r -O2 -fsplit-loops -ftree-vectorize -fgnu89-inline -quiet
foo-decimal64.i
Starting program: /home/meissner/fsf-build-ppc64le/trunk/gcc/cc1 -O2
-fsplit-loops -ftree-vectorize -fgnu89-inline -quiet foo-decimal64.i
decimal64.c: In function ‘decDigitsToDPD’:
decimal64.c:662:6: error: missing definition
for SSA_NAME: _292 in statement:
target_205 = _292;
Breakpoint 2, internal_error (gmsgid=0x11acd0d0 "verify_ssa failed") at
/home/meissner/fsf-src/trunk/gcc/diagnostic.c:1787
1787 global_dc->diagnostic_group_nesting_depth++;
(gdb) where
#0 internal_error (gmsgid=0x11acd0d0 "verify_ssa failed") at
/home/meissner/fsf-src/trunk/gcc/diagnostic.c:1787
#1 0x0000000010e2efac in verify_ssa (check_modified_stmt=<optimized out>,
check_ssa_operands=<optimized out>) at
/home/meissner/fsf-src/trunk/gcc/tree-ssa.c:1208
#2 0x00000000109b6ea0 in execute_function_todo (fn=0x7ffff5a41550,
data=<optimized out>) at /home/meissner/fsf-src/trunk/gcc/passes.c:1992
#3 0x00000000109b80d4 in do_per_function (callback=<optimized out>,
data=<optimized out>) at /home/meissner/fsf-src/trunk/gcc/passes.c:1640
#4 0x00000000109b82fc in execute_todo (flags=<optimized out>) at
/home/meissner/fsf-src/trunk/gcc/passes.c:2039
#5 0x00000000109bbcc4 in execute_one_pass (pass=pass@entry=<opt_pass*
0x12230e70 "vect"(166)>) at /home/meissner/fsf-src/trunk/gcc/passes.c:2539
#6 0x00000000109bca64 in execute_pass_list_1 (pass=<opt_pass* 0x12230e70
"vect"(166)>) at /home/meissner/fsf-src/trunk/gcc/passes.c:2590
#7 0x00000000109bca7c in execute_pass_list_1 (pass=<opt_pass* 0x12230680
"loop"(145)>) at /home/meissner/fsf-src/trunk/gcc/passes.c:2591
#8 0x00000000109bca7c in execute_pass_list_1 (pass=<opt_pass* 0x1222f310
"*all_optimizations"(-1)>) at /home/meissner/fsf-src/trunk/gcc/passes.c:2591
#9 0x00000000109bcb08 in execute_pass_list (fn=<optimized out>,
pass=<optimized out>) at /home/meissner/fsf-src/trunk/gcc/passes.c:2601
#10 0x0000000010474e00 in cgraph_node::expand (this=<cgraph_node * const
0x7ffff59c2d00 "decDigitsToDPD"/37>) at
/home/meissner/fsf-src/trunk/gcc/context.h:48
#11 0x000000001047689c in expand_all_functions () at
/home/meissner/fsf-src/trunk/gcc/cgraphunit.c:2470
#12 symbol_table::compile (this=this@entry=0x7ffff5780000) at
/home/meissner/fsf-src/trunk/gcc/cgraphunit.c:2820
#13 0x000000001047a654 in symbol_table::compile (this=0x7ffff5780000) at
/home/meissner/fsf-src/trunk/gcc/cgraphunit.c:3000
#14 symbol_table::finalize_compilation_unit (this=0x7ffff5780000) at
/home/meissner/fsf-src/trunk/gcc/cgraphunit.c:3000
#15 0x0000000010afb2b8 in compile_file () at
/home/meissner/fsf-src/trunk/gcc/toplev.c:483
#16 0x00000000101de57c in do_compile () at
/home/meissner/fsf-src/trunk/gcc/toplev.c:2273
#17 toplev::main (this=0x7fffffffdc40, argc=<optimized out>, argv=<optimized
out>) at /home/meissner/fsf-src/trunk/gcc/toplev.c:2412
#18 0x00000000101e0718 in main (argc=<optimized out>, argv=0x7fffffffe068) at
/home/meissner/fsf-src/trunk/gcc/main.c:39
I did a pull later in the day, and I got Peter Bergner's lower-subreg patches,
but it did not help with the failure. The git hash for the branch is
918b89b7623b6c42b09f37b7e3ef807d1abbabb8.
I fell back to the version of the compiler I pulled on March 27th with a git
hash of 71d69548a1b2c85220ac6354564fd272beb9263f, and it builds Spec 2017 gcc_r
fine with my normal options (-Ofast -mveclibabi=mass -mrecip, etc.).
I did a diff of the gcc/config/rs6000 files, and the following 3 files were
modified:
gcc/config/rs6000/rs6000-call.c
gcc/config/rs6000/rs6000.c
gcc/config/rs6000/rs6000.md
However, if I replace these files in the 4/1 compiler, it still fails. So it
does not appear to be due to PowerPC specific changes.
I'm including an attachment of decimal64.i that shows the error with the -O2
-fsplit-loops -ftree-vectorize -fgnu89-inline options.
