4e428907c5
We generate a lot of pointless dead blocks during the AST to SSA conversion. There are a few commonly occurring kinds of statements that contain neither variables nor code and that switch to a new block themselves. Stop making dead blocks for them. For the code in #19379, this reduces compilation wall time by 36% and max rss by 28%. This also helps a little for regular code, particularly code heavy on switch statements. name old time/op new time/op delta Template 231ms ± 3% 230ms ± 5% ~ (p=0.402 n=17+16) Unicode 101ms ± 4% 103ms ± 5% ~ (p=0.221 n=19+18) GoTypes 635ms ± 5% 625ms ± 4% ~ (p=0.063 n=20+18) Compiler 2.93s ± 2% 2.89s ± 2% -1.22% (p=0.003 n=20+19) SSA 4.53s ± 3% 4.52s ± 3% ~ (p=0.380 n=20+19) Flate 132ms ± 4% 133ms ± 5% ~ (p=0.647 n=20+19) GoParser 161ms ± 3% 161ms ± 4% ~ (p=0.749 n=20+19) Reflect 403ms ± 4% 397ms ± 3% -1.53% (p=0.030 n=20+19) Tar 121ms ± 2% 121ms ± 8% ~ (p=0.544 n=19+19) XML 225ms ± 3% 224ms ± 4% ~ (p=0.396 n=20+19) name old user-ns/op new user-ns/op delta Template 302user-ms ± 1% 297user-ms ± 7% -1.49% (p=0.048 n=15+18) Unicode 142user-ms ± 3% 143user-ms ± 5% ~ (p=0.363 n=19+17) GoTypes 852user-ms ± 5% 851user-ms ± 3% ~ (p=0.851 n=20+18) Compiler 4.11user-s ± 6% 3.98user-s ± 3% -3.08% (p=0.000 n=20+19) SSA 6.91user-s ± 5% 6.82user-s ± 7% ~ (p=0.113 n=20+19) Flate 164user-ms ± 4% 168user-ms ± 4% +2.42% (p=0.001 n=18+19) GoParser 207user-ms ± 4% 206user-ms ± 4% ~ (p=0.176 n=20+18) Reflect 509user-ms ± 4% 505user-ms ± 4% ~ (p=0.113 n=20+19) Tar 153user-ms ± 7% 151user-ms ± 9% ~ (p=0.283 n=20+19) XML 284user-ms ± 4% 282user-ms ± 4% ~ (p=0.270 n=20+19) name old alloc/op new alloc/op delta Template 42.6MB ± 0% 41.9MB ± 0% -1.55% (p=0.000 n=19+19) Unicode 31.7MB ± 0% 31.7MB ± 0% ~ (p=0.828 n=20+18) GoTypes 124MB ± 0% 121MB ± 0% -2.11% (p=0.000 n=20+17) Compiler 534MB ± 0% 523MB ± 0% -2.06% (p=0.000 n=20+19) SSA 989MB ± 0% 977MB ± 0% -1.28% (p=0.000 n=20+19) Flate 27.8MB ± 0% 27.5MB ± 0% -0.98% (p=0.000 n=20+19) GoParser 34.3MB ± 0% 34.0MB ± 0% -0.81% (p=0.000 n=20+19) Reflect 84.6MB ± 0% 82.9MB ± 0% -2.00% (p=0.000 n=17+18) Tar 28.8MB ± 0% 28.3MB ± 0% -1.52% (p=0.000 n=16+18) XML 47.2MB ± 0% 45.8MB ± 0% -2.99% (p=0.000 n=20+19) name old allocs/op new allocs/op delta Template 421k ± 1% 419k ± 1% -0.41% (p=0.001 n=20+19) Unicode 338k ± 1% 338k ± 1% ~ (p=0.478 n=20+19) GoTypes 1.28M ± 0% 1.28M ± 0% -0.36% (p=0.000 n=20+18) Compiler 5.06M ± 0% 5.03M ± 0% -0.63% (p=0.000 n=20+19) SSA 9.14M ± 0% 9.11M ± 0% -0.34% (p=0.000 n=20+19) Flate 267k ± 1% 266k ± 1% ~ (p=0.149 n=20+19) GoParser 347k ± 0% 347k ± 1% ~ (p=0.103 n=19+19) Reflect 1.07M ± 0% 1.07M ± 0% -0.42% (p=0.000 n=16+18) Tar 274k ± 0% 273k ± 1% ~ (p=0.116 n=19+19) XML 449k ± 0% 446k ± 1% -0.60% (p=0.000 n=20+19) Updates #19379 Change-Id: Ie798c347a0c081f5e349e1529880bebaae290967 Reviewed-on: https://go-review.googlesource.com/37760 Reviewed-by: David Chase <drchase@google.com>
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