$ echo 'int main() { }' | gcc -xc - -Q
main
Analyzing compilation unit
Performing interprocedural optimizations
<*free_lang_data> {heap 868k} <visibility> {heap 868k} <build_ssa_passes> {heap 868k} <opt_local_passes> {heap 1060k} <remove_symbols> {heap 1060k} <targetclone> {heap 1060k} <free-fnsummary> {heap 1060k}Streaming LTO
<whole-program> {heap 1060k} <hsa> {heap 1060k} <fnsummary> {heap 1060k} <inline> {heap 1060k} <free-fnsummary> {heap 1060k} <single-use> {heap 1060k} <comdats> {heap 1060k}Assembling functions:
<materialize-all-clones> {heap 1060k} <simdclone> {heap 1060k} main
Time variable usr sys wall GGC
phase setup : 0.00 ( 0%) 0.01 (100%) 0.00 ( 0%) 1240 kB ( 86%)
phase parsing : 0.00 ( 0%) 0.00 ( 0%) 0.13 ( 45%) 132 kB ( 9%)
phase opt and generate : 0.00 ( 0%) 0.00 ( 0%) 0.11 ( 38%) 58 kB ( 4%)
callgraph optimization : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 0 kB ( 0%)
callgraph ipa passes : 0.00 ( 0%) 0.00 ( 0%) 0.02 ( 7%) 5 kB ( 0%)
trivially dead code : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 0 kB ( 0%)
parser (global) : 0.00 ( 0%) 0.00 ( 0%) 0.13 ( 45%) 122 kB ( 8%)
tree eh : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 0 kB ( 0%)
tree CFG construction : 0.00 ( 0%) 0.00 ( 0%) 0.02 ( 7%) 1 kB ( 0%)
tree SSA other : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 0 kB ( 0%)
integrated RA : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 24 kB ( 2%)
reload : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 0 kB ( 0%)
final : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 1 kB ( 0%)
initialize rtl : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 12 kB ( 1%)
rest of compilation : 0.00 ( 0%) 0.00 ( 0%) 0.01 ( 3%) 2 kB ( 0%)
TOTAL : 0.00 0.01 0.29 1441 kB
gcc --help=param -Q shows the parameters's minimal, maximal and default values.