https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83325
Bug ID: 83325
Summary: Compile time hog w/ -Os -fwrapv
Product: gcc
Version: unknown
Status: UNCONFIRMED
Keywords: compile-time-hog
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: asolokha at gmx dot com
Target Milestone: ---
Created attachment 42814
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42814&action=edit
Testcase
gcc-8.0.0-alpha20171126 snapshot (r255155) takes indefinite time when compiling
the attached testcase w/ -Os -fwrapv for 32-bit BE powerpc targets (but not for
x86_64 in my setup):
% timeout 20 powerpc-e300c3-linux-gnu-gcc-8.0.0-alpha20171126 -Os -fwrapv -w -c
zxwg8bwp.c
zsh: exit 124 timeout 20 powerpc-e300c3-linux-gnu-gcc-8.0.0-alpha20171126 -Os
-fwrapv -w -c
Some perf top entries:
13.74% cc1 [.] operand_equal_p
13.20% cc1 [.] visit_use
8.57% cc1 [.] hash_table<vn_phi_hasher,
xcallocator>::find_slot_with_hash
7.17% cc1 [.] VN_INFO
5.49% cc1 [.] vn_phi_eq
4.77% cc1 [.] vn_phi_compute_hash
4.54% cc1 [.] inchash::add_expr
3.61% cc1 [.] expressions_equal_p
3.22% cc1 [.] tree_strip_nop_conversions
3.05% cc1 [.] set_ssa_val_to
2.44% cc1 [.] DFS
2.31% cc1 [.] iterative_hash_hashval_t
2.24% cc1 [.] element_precision
2.03% cc1 [.] ssa_undefined_value_p
1.64% cc1 [.] ssa_defined_default_def_p
1.24% cc1 [.] mark_use_processed
1.17% cc1 [.] is_gimple_min_invariant
1.15% cc1 [.] vec<tree_node*, va_heap,
vl_ptr>::safe_grow
gcc 7.2.0 also takes indefinite time when compiling the attached snippet for
x86_64-pc-linux-gnu w/ the same options.
This may be a duplicate of PR82952.
