cmd/internal/obj/loong64: realize all unconditional jumps with B/BL
The current practice of using the "PC-relative" `BEQ ZERO, ZERO` for
short jumps is inherited from the MIPS port, where the pre-R6 long
jumps are PC-regional instead of PC-relative. This quirk is not
present in LoongArch from the very beginning so there is no reason to
keep the behavior any more.
While at it, simplify the code to not place anything in the jump offset
field if a relocation is to take place. (It may be relic of a previous
REL-era treatment where the addend is to be stored in the instruction
word, but again, loong64 is exclusively RELA from day 1 so no point in
doing so either.)
Benchmark shows very slight improvement on a 3A5000 box, indicating the
LA464 micro-architecture presumably *not* seeing the always-true BEQs as
equivalent to B:
goos: linux
goarch: loong64
pkg: test/bench/go1
│
2ef70d9d0f │ this CL │
│ sec/op │ sec/op vs base │
BinaryTree17 14.57 ± 4% 14.54 ± 1% ~ (p=0.353 n=10)
Fannkuch11 3.570 ± 0% 3.570 ± 0% ~ (p=0.529 n=10)
FmtFprintfEmpty 92.84n ± 0% 92.84n ± 0% ~ (p=0.970 n=10)
FmtFprintfString 150.0n ± 0% 149.9n ± 0% ~ (p=0.350 n=10)
FmtFprintfInt 153.3n ± 0% 153.3n ± 0% ~ (p=1.000 n=10) ¹
FmtFprintfIntInt 235.8n ± 0% 235.8n ± 0% ~ (p=0.963 n=10)
FmtFprintfPrefixedInt 318.5n ± 0% 318.5n ± 0% ~ (p=0.474 n=10)
FmtFprintfFloat 410.4n ± 0% 410.4n ± 0% ~ (p=0.628 n=10)
FmtManyArgs 944.9n ± 0% 945.0n ± 0% ~ (p=0.240 n=10)
GobDecode 13.97m ± 12% 12.83m ± 21% ~ (p=0.165 n=10)
GobEncode 17.84m ± 5% 18.60m ± 4% ~ (p=0.123 n=10)
Gzip 421.0m ± 0% 421.0m ± 0% ~ (p=0.579 n=10)
Gunzip 89.80m ± 0% 89.77m ± 0% ~ (p=0.529 n=10)
HTTPClientServer 86.54µ ± 1% 86.25µ ± 0% -0.33% (p=0.003 n=10)
JSONEncode 18.57m ± 0% 18.57m ± 0% ~ (p=0.353 n=10)
JSONDecode 77.48m ± 0% 77.30m ± 0% -0.23% (p=0.035 n=10)
Mandelbrot200 7.217m ± 0% 7.217m ± 0% ~ (p=0.436 n=10)
GoParse 7.599m ± 2% 7.632m ± 1% ~ (p=0.353 n=10)
RegexpMatchEasy0_32 140.1n ± 0% 140.1n ± 0% ~ (p=0.582 n=10)
RegexpMatchEasy0_1K 1.538µ ± 0% 1.538µ ± 0% ~ (p=1.000 n=10) ¹
RegexpMatchEasy1_32 161.7n ± 0% 161.7n ± 0% ~ (p=1.000 n=10) ¹
RegexpMatchEasy1_1K 1.632µ ± 0% 1.632µ ± 0% ~ (p=1.000 n=10) ¹
RegexpMatchMedium_32 1.369µ ± 0% 1.369µ ± 0% ~ (p=1.000 n=10)
RegexpMatchMedium_1K 39.96µ ± 0% 39.96µ ± 0% +0.01% (p=0.010 n=10)
RegexpMatchHard_32 2.099µ ± 0% 2.099µ ± 0% ~ (p=1.000 n=10) ¹
RegexpMatchHard_1K 62.50µ ± 0% 62.50µ ± 0% ~ (p=0.099 n=10)
Revcomp 1.349 ± 0% 1.347 ± 0% -0.14% (p=0.001 n=10)
Template 118.4m ± 0% 118.0m ± 0% -0.36% (p=0.023 n=10)
TimeParse 407.8n ± 0% 407.9n ± 0% +0.02% (p=0.000 n=10)
TimeFormat 508.0n ± 0% 507.9n ± 0% ~ (p=0.421 n=10)
geomean 103.5µ 103.3µ -0.17%
¹ all samples are equal
│
2ef70d9d0f │ this CL │
│ B/s │ B/s vs base │
GobDecode 52.67Mi ± 11% 57.04Mi ± 17% ~ (p=0.149 n=10)
GobEncode 41.03Mi ± 4% 39.35Mi ± 4% ~ (p=0.118 n=10)
Gzip 43.95Mi ± 0% 43.95Mi ± 0% ~ (p=0.428 n=10)
Gunzip 206.1Mi ± 0% 206.1Mi ± 0% ~ (p=0.399 n=10)
JSONEncode 99.64Mi ± 0% 99.66Mi ± 0% ~ (p=0.304 n=10)
JSONDecode 23.88Mi ± 0% 23.94Mi ± 0% +0.22% (p=0.030 n=10)
GoParse 7.267Mi ± 2% 7.238Mi ± 1% ~ (p=0.360 n=10)
RegexpMatchEasy0_32 217.8Mi ± 0% 217.8Mi ± 0% -0.00% (p=0.006 n=10)
RegexpMatchEasy0_1K 635.0Mi ± 0% 635.0Mi ± 0% ~ (p=0.194 n=10)
RegexpMatchEasy1_32 188.7Mi ± 0% 188.7Mi ± 0% ~ (p=0.338 n=10)
RegexpMatchEasy1_1K 598.5Mi ± 0% 598.5Mi ± 0% -0.00% (p=0.000 n=10)
RegexpMatchMedium_32 22.30Mi ± 0% 22.30Mi ± 0% ~ (p=0.211 n=10)
RegexpMatchMedium_1K 24.43Mi ± 0% 24.43Mi ± 0% ~ (p=1.000 n=10)
RegexpMatchHard_32 14.54Mi ± 0% 14.54Mi ± 0% ~ (p=0.474 n=10)
RegexpMatchHard_1K 15.62Mi ± 0% 15.62Mi ± 0% ~ (p=1.000 n=10) ¹
Revcomp 179.7Mi ± 0% 180.0Mi ± 0% +0.14% (p=0.001 n=10)
Template 15.63Mi ± 0% 15.68Mi ± 0% +0.34% (p=0.022 n=10)
geomean 60.29Mi 60.44Mi +0.24%
¹ all samples are equal
Change-Id: I112dd663c49567386ea75dd4966a9f8127ffb90e
Reviewed-on: https://go-review.googlesource.com/c/go/+/478075
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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