https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80747
Bug ID: 80747
Summary: gcc.dg/tree-ssa/tailrecursion-4.c fails with ICE when
compiled with options "-fprofile-use
-freorder-blocks-and-partition"
Product: gcc
Version: 6.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: zwzhangwen.zhang at huawei dot com
Target Milestone: ---
Created attachment 41355
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41355&action=edit
my patch for fix this ICE.
When I test bb-reorder pass with deja testcase, this ICE has been found.
Compile line is as follow:
./install/bin/mips-sde-elf-gcc -fprofile-use -freorder-blocks-and-partition
-O1 -foptimize-sibling-calls -S tailrecursion-4.c
The ICE information is:
tailrecursion-4.c: In function 't':
tailrecursion-4.c:16:1: internal compiler error: in df_compact_blocks, at
df-core.c:1743
}
^
0x859fce df_compact_blocks()
/home/wangtao/SDK_CPU_HCC_TEST/hi1822/SDK_CPU_HCC/build/script/1822/hi1822_build_dir/src/gcc-6.3.0/gcc/df-core.c:1743
0x11f3abe compact_blocks()
/home/wangtao/SDK_CPU_HCC_TEST/hi1822/SDK_CPU_HCC/build/script/1822/hi1822_build_dir/src/gcc-6.3.0/gcc/cfg.c:159
0x813fea relink_block_chain(bool)
/home/wangtao/SDK_CPU_HCC_TEST/hi1822/SDK_CPU_HCC/build/script/1822/hi1822_build_dir/src/gcc-6.3.0/gcc/cfgrtl.c:3654
0x11e85c9 reorder_basic_blocks
/home/wangtao/SDK_CPU_HCC_TEST/hi1822/SDK_CPU_HCC/build/script/1822/hi1822_build_dir/src/gcc-6.3.0/gcc/bb-reorder.c:2501
0x11e862c execute
/home/wangtao/SDK_CPU_HCC_TEST/hi1822/SDK_CPU_HCC/build/script/1822/hi1822_build_dir/src/gcc-6.3.0/gcc/bb-reorder.c:2591
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.
I debug it, and find that there is a bug when reorder bb according to cold/hot
partition in function reorder_basic_blocks_simple. In
find_rarely_executed_basic_blocks_and_crossing_edges will not set partition for
the first bb(cfun->cfg->x_entry_block_ptr), but reorderring bb in
reorder_basic_blocks_simple may be according to the partition of the first bb.
Therefore, after reorderring, some bbs have been lost, which triggered ICE.
According to the above, I set a default partition for reorderring bb when
partition is neither hot nor cold, which as the attachment shows. Please check
my solution and give some suggestion.
Thanks a lot.
