https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119516
Sam James <sjames at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |compile-time-hog
--- Comment #1 from Sam James <sjames at gcc dot gnu.org> ---
At -O1 with checking:
```
$ g++ a.cxx -std=c++26 -O1 -ftime-report
Time variable wall GGC
phase setup : 0.00 ( 0%) 1813k ( 1%)
phase parsing : 0.96 ( 25%) 134M ( 58%)
phase lang. deferred : 0.42 ( 11%) 33M ( 15%)
phase opt and generate : 2.45 ( 64%) 61M ( 27%)
|name lookup : 0.15 ( 4%) 4534k ( 2%)
|overload resolution : 0.37 ( 10%) 37M ( 16%)
garbage collection : 0.31 ( 8%) 0 ( 0%)
callgraph construction : 0.03 ( 1%) 2445k ( 1%)
callgraph optimization : 0.02 ( 0%) 12k ( 0%)
callgraph functions expansion : 1.83 ( 48%) 33M ( 14%)
callgraph ipa passes : 0.54 ( 14%) 20M ( 9%)
ipa function summary : 0.02 ( 0%) 759k ( 0%)
ipa inlining heuristics : 0.01 ( 0%) 1013k ( 0%)
ipa pure const : 0.01 ( 0%) 39k ( 0%)
ipa modref : 0.01 ( 0%) 167k ( 0%)
cfg cleanup : 0.01 ( 0%) 8008 ( 0%)
CFG verifier : 0.13 ( 3%) 0 ( 0%)
trivially dead code : 0.01 ( 0%) 0 ( 0%)
df scan insns : 0.01 ( 0%) 2544 ( 0%)
df live regs : 0.03 ( 1%) 0 ( 0%)
df live&initialized regs : 0.01 ( 0%) 0 ( 0%)
df reg dead/unused notes : 0.02 ( 0%) 634k ( 0%)
alias analysis : 0.01 ( 0%) 719k ( 0%)
alias stmt walking : 0.02 ( 1%) 155k ( 0%)
preprocessing : 0.07 ( 2%) 4612k ( 2%)
parser (global) : 0.12 ( 3%) 49M ( 21%)
parser struct body : 0.11 ( 3%) 22M ( 10%)
parser function body : 0.02 ( 1%) 1874k ( 1%)
parser inl. func. body : 0.06 ( 2%) 6975k ( 3%)
parser inl. meth. body : 0.12 ( 3%) 13M ( 6%)
template instantiation : 0.47 ( 12%) 55M ( 24%)
constant expression evaluation : 0.05 ( 1%) 2622k ( 1%)
constraint normalization : 0.03 ( 1%) 1844k ( 1%)
constraint satisfaction : 0.11 ( 3%) 8590k ( 4%)
early inlining heuristics : 0.01 ( 0%) 466k ( 0%)
inline parameters : 0.02 ( 1%) 1374k ( 1%)
integration : 0.07 ( 2%) 17M ( 8%)
tree gimplify : 0.02 ( 1%) 3852k ( 2%)
tree CFG construction : 0.00 ( 0%) 1555k ( 1%)
tree CFG cleanup : 0.05 ( 1%) 117k ( 0%)
tree copy propagation : 0.01 ( 0%) 17k ( 0%)
tree PTA : 0.03 ( 1%) 321k ( 0%)
tree SSA rewrite : 0.01 ( 0%) 1033k ( 0%)
tree SSA incremental : 0.02 ( 1%) 978k ( 0%)
tree operand scan : 0.01 ( 0%) 3023k ( 1%)
dominator optimization : 0.12 ( 3%) 2120k ( 1%)
backwards jump threading : 0.01 ( 0%) 61k ( 0%)
tree SRA : 0.01 ( 0%) 622k ( 0%)
tree CCP : 0.05 ( 1%) 392k ( 0%)
tree FRE : 0.04 ( 1%) 632k ( 0%)
tree code sinking : 0.01 ( 0%) 747k ( 0%)
tree linearize phis : 0.01 ( 0%) 109k ( 0%)
tree forward propagate : 0.03 ( 1%) 345k ( 0%)
tree conservative DCE : 0.01 ( 0%) 40k ( 0%)
tree aggressive DCE : 0.01 ( 0%) 42k ( 0%)
tree DSE : 0.02 ( 0%) 66k ( 0%)
tree loop invariant motion : 0.01 ( 0%) 10k ( 0%)
tree iv optimization : 0.01 ( 0%) 645k ( 0%)
tree copy headers : 0.01 ( 0%) 184k ( 0%)
tree SSA verifier : 0.20 ( 5%) 0 ( 0%)
tree STMT verifier : 0.39 ( 10%) 0 ( 0%)
tree modref : 0.01 ( 0%) 325k ( 0%)
callgraph verifier : 0.02 ( 1%) 0 ( 0%)
dominance computation : 0.07 ( 2%) 0 ( 0%)
expand vars : 0.01 ( 0%) 394k ( 0%)
expand : 0.03 ( 1%) 4796k ( 2%)
forward prop : 0.02 ( 1%) 99k ( 0%)
CSE : 0.02 ( 1%) 81k ( 0%)
dead store elim1 : 0.02 ( 1%) 356k ( 0%)
dead store elim2 : 0.02 ( 0%) 540k ( 0%)
loop init : 0.05 ( 1%) 1583k ( 1%)
branch prediction : 0.01 ( 0%) 245k ( 0%)
combiner : 0.05 ( 1%) 1738k ( 1%)
if-conversion : 0.01 ( 0%) 279k ( 0%)
integrated RA : 0.08 ( 2%) 3314k ( 1%)
LRA non-specific : 0.04 ( 1%) 435k ( 0%)
LRA virtuals elimination : 0.01 ( 0%) 417k ( 0%)
LRA reload inheritance : 0.01 ( 0%) 48k ( 0%)
LRA create live ranges : 0.02 ( 0%) 81k ( 0%)
reload CSE regs : 0.02 ( 1%) 372k ( 0%)
thread pro- & epilogue : 0.02 ( 0%) 166k ( 0%)
hard reg cprop : 0.01 ( 0%) 9456 ( 0%)
reorder blocks : 0.01 ( 0%) 359k ( 0%)
shorten branches : 0.01 ( 0%) 360 ( 0%)
final : 0.02 ( 0%) 1156k ( 0%)
access analysis : 0.02 ( 0%) 18k ( 0%)
rest of compilation : 0.04 ( 1%) 726k ( 0%)
remove unused locals : 0.01 ( 0%) 11k ( 0%)
address taken : 0.01 ( 0%) 0 ( 0%)
verify RTL sharing : 0.09 ( 2%) 0 ( 0%)
repair loop structures : 0.01 ( 0%) 0 ( 0%)
TOTAL : 3.83 231M
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --enable-checking=release to disable checks.
```
At -O2 with checking:
```
$ g++ a.cxx -std=c++26 -O2 -ftime-report
Time variable wall GGC
phase setup : 0.01 ( 0%) 1813k ( 1%)
phase parsing : 2.50 ( 24%) 134M ( 54%)
phase lang. deferred : 0.87 ( 8%) 33M ( 13%)
phase opt and generate : 7.19 ( 68%) 80M ( 32%)
|name lookup : 0.34 ( 3%) 4534k ( 2%)
|overload resolution : 0.77 ( 7%) 37M ( 15%)
garbage collection : 1.25 ( 12%) 0 ( 0%)
dump files : 0.01 ( 0%) 0 ( 0%)
callgraph construction : 0.08 ( 1%) 2515k ( 1%)
callgraph optimization : 0.05 ( 1%) 16k ( 0%)
callgraph functions expansion : 5.28 ( 50%) 47M ( 19%)
callgraph ipa passes : 1.71 ( 16%) 24M ( 10%)
ipa function summary : 0.02 ( 0%) 552k ( 0%)
ipa dead code removal : 0.01 ( 0%) 0 ( 0%)
ipa cp : 0.03 ( 0%) 441k ( 0%)
ipa inlining heuristics : 0.06 ( 1%) 1958k ( 1%)
ipa function splitting : 0.01 ( 0%) 450k ( 0%)
ipa pure const : 0.02 ( 0%) 32k ( 0%)
ipa icf : 0.01 ( 0%) 0 ( 0%)
ipa SRA : 0.01 ( 0%) 253k ( 0%)
ipa modref : 0.02 ( 0%) 207k ( 0%)
cfg cleanup : 0.07 ( 1%) 626k ( 0%)
CFG verifier : 0.28 ( 3%) 0 ( 0%)
trivially dead code : 0.02 ( 0%) 0 ( 0%)
df scan insns : 0.02 ( 0%) 2736 ( 0%)
df reaching defs : 0.05 ( 0%) 0 ( 0%)
df live regs : 0.16 ( 2%) 0 ( 0%)
df live&initialized regs : 0.06 ( 1%) 0 ( 0%)
df use-def / def-use chains : 0.03 ( 0%) 0 ( 0%)
df reg dead/unused notes : 0.05 ( 0%) 645k ( 0%)
register information : 0.01 ( 0%) 0 ( 0%)
alias analysis : 0.04 ( 0%) 1376k ( 1%)
alias stmt walking : 0.06 ( 1%) 245k ( 0%)
register scan : 0.01 ( 0%) 10k ( 0%)
rebuild jump labels : 0.01 ( 0%) 96 ( 0%)
preprocessing : 0.14 ( 1%) 4612k ( 2%)
parser (global) : 0.30 ( 3%) 49M ( 20%)
parser struct body : 0.29 ( 3%) 22M ( 9%)
parser function body : 0.04 ( 0%) 1874k ( 1%)
parser inl. func. body : 0.20 ( 2%) 6975k ( 3%)
parser inl. meth. body : 0.28 ( 3%) 13M ( 6%)
template instantiation : 0.96 ( 9%) 55M ( 22%)
constant expression evaluation : 0.09 ( 1%) 2622k ( 1%)
constraint normalization : 0.05 ( 1%) 1844k ( 1%)
constraint satisfaction : 0.22 ( 2%) 8590k ( 3%)
early inlining heuristics : 0.02 ( 0%) 512k ( 0%)
inline parameters : 0.04 ( 0%) 1419k ( 1%)
integration : 0.16 ( 2%) 18M ( 7%)
tree gimplify : 0.05 ( 0%) 3921k ( 2%)
tree eh : 0.01 ( 0%) 476k ( 0%)
tree CFG construction : 0.01 ( 0%) 1590k ( 1%)
tree CFG cleanup : 0.12 ( 1%) 224k ( 0%)
tree tail merge : 0.01 ( 0%) 360k ( 0%)
tree VRP : 0.14 ( 1%) 838k ( 0%)
tree Early VRP : 0.07 ( 1%) 946k ( 0%)
tree copy propagation : 0.02 ( 0%) 20k ( 0%)
tree PTA : 0.10 ( 1%) 390k ( 0%)
tree SSA rewrite : 0.01 ( 0%) 1046k ( 0%)
tree SSA incremental : 0.06 ( 1%) 1265k ( 0%)
tree operand scan : 0.02 ( 0%) 3446k ( 1%)
dominator optimization : 0.20 ( 2%) 2187k ( 1%)
backwards jump threading : 0.24 ( 2%) 2023k ( 1%)
tree SRA : 0.03 ( 0%) 742k ( 0%)
tree CCP : 0.10 ( 1%) 363k ( 0%)
tree reassociation : 0.01 ( 0%) 13k ( 0%)
tree PRE : 0.09 ( 1%) 1021k ( 0%)
tree FRE : 0.12 ( 1%) 838k ( 0%)
tree code sinking : 0.01 ( 0%) 786k ( 0%)
tree linearize phis : 0.01 ( 0%) 119k ( 0%)
tree forward propagate : 0.04 ( 0%) 339k ( 0%)
tree conservative DCE : 0.01 ( 0%) 46k ( 0%)
tree aggressive DCE : 0.02 ( 0%) 949k ( 0%)
tree DSE : 0.03 ( 0%) 196k ( 0%)
tree loop invariant motion : 0.01 ( 0%) 12k ( 0%)
tree canonical iv : 0.01 ( 0%) 96k ( 0%)
complete unrolling : 0.01 ( 0%) 231k ( 0%)
tree vectorization : 0.01 ( 0%) 209k ( 0%)
tree slp vectorization : 0.04 ( 0%) 2509k ( 1%)
tree iv optimization : 0.02 ( 0%) 670k ( 0%)
tree copy headers : 0.02 ( 0%) 193k ( 0%)
tree SSA verifier : 0.43 ( 4%) 0 ( 0%)
tree STMT verifier : 0.89 ( 8%) 0 ( 0%)
tree strlen optimization : 0.02 ( 0%) 104k ( 0%)
tree modref : 0.02 ( 0%) 482k ( 0%)
callgraph verifier : 0.07 ( 1%) 0 ( 0%)
dominance frontiers : 0.01 ( 0%) 0 ( 0%)
dominance computation : 0.18 ( 2%) 0 ( 0%)
out of ssa : 0.01 ( 0%) 9456 ( 0%)
expand vars : 0.01 ( 0%) 397k ( 0%)
expand : 0.06 ( 1%) 4759k ( 2%)
post expand cleanups : 0.01 ( 0%) 557k ( 0%)
lower subreg : 0.01 ( 0%) 17k ( 0%)
forward prop : 0.06 ( 1%) 94k ( 0%)
CSE : 0.10 ( 1%) 299k ( 0%)
dead code elimination : 0.01 ( 0%) 0 ( 0%)
dead store elim1 : 0.03 ( 0%) 336k ( 0%)
dead store elim2 : 0.04 ( 0%) 575k ( 0%)
loop init : 0.12 ( 1%) 2226k ( 1%)
loop unrolling : 0.02 ( 0%) 108k ( 0%)
CPROP : 0.08 ( 1%) 1059k ( 0%)
PRE : 0.03 ( 0%) 122k ( 0%)
CSE 2 : 0.06 ( 1%) 190k ( 0%)
branch prediction : 0.02 ( 0%) 249k ( 0%)
combiner : 0.10 ( 1%) 2128k ( 1%)
late combiner : 0.06 ( 1%) 98k ( 0%)
if-conversion : 0.01 ( 0%) 282k ( 0%)
integrated RA : 0.18 ( 2%) 3802k ( 1%)
LRA non-specific : 0.08 ( 1%) 474k ( 0%)
LRA virtuals elimination : 0.02 ( 0%) 498k ( 0%)
LRA reload inheritance : 0.01 ( 0%) 134k ( 0%)
LRA create live ranges : 0.04 ( 0%) 78k ( 0%)
LRA hard reg assignment : 0.01 ( 0%) 0 ( 0%)
LRA rematerialization : 0.01 ( 0%) 0 ( 0%)
reload CSE regs : 0.06 ( 1%) 737k ( 0%)
ree : 0.01 ( 0%) 19k ( 0%)
thread pro- & epilogue : 0.03 ( 0%) 160k ( 0%)
peephole 2 : 0.01 ( 0%) 76k ( 0%)
hard reg cprop : 0.02 ( 0%) 6696 ( 0%)
scheduling 2 : 0.13 ( 1%) 241k ( 0%)
machine dep reorg : 0.01 ( 0%) 42k ( 0%)
reorder blocks : 0.01 ( 0%) 380k ( 0%)
shorten branches : 0.01 ( 0%) 0 ( 0%)
final : 0.03 ( 0%) 1160k ( 0%)
access analysis : 0.04 ( 0%) 19k ( 0%)
ext dce : 0.01 ( 0%) 0 ( 0%)
fold mem offsets : 0.01 ( 0%) 79k ( 0%)
rest of compilation : 0.08 ( 1%) 468k ( 0%)
remove unused locals : 0.03 ( 0%) 1504 ( 0%)
address taken : 0.01 ( 0%) 0 ( 0%)
verify RTL sharing : 0.22 ( 2%) 0 ( 0%)
repair loop structures : 0.01 ( 0%) 384 ( 0%)
TOTAL : 10.57 250M
Extra diagnostic checks enabled; compiler may run slowly.
Configure with --enable-checking=release to disable checks.
```
.. so I can't yet reproduce.
