cmd/internal/gc: inline runtime.getg
This more closely restores what the old C runtime did.
(In C, g was an 'extern register' with the same effective
implementation as in this CL.)
On a late 2012 MacBookPro10,2, best of 5 old vs best of 5 new:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 4981312777 4463426605 -10.40%
BenchmarkFannkuch11 3046495712 3006819428 -1.30%
BenchmarkFmtFprintfEmpty 89.3 79.8 -10.64%
BenchmarkFmtFprintfString 284 262 -7.75%
BenchmarkFmtFprintfInt 282 262 -7.09%
BenchmarkFmtFprintfIntInt 480 448 -6.67%
BenchmarkFmtFprintfPrefixedInt 382 358 -6.28%
BenchmarkFmtFprintfFloat 529 486 -8.13%
BenchmarkFmtManyArgs 1849 1773 -4.11%
BenchmarkGobDecode 12835963 11794385 -8.11%
BenchmarkGobEncode 10527170 10288422 -2.27%
BenchmarkGzip 436109569 438422516 +0.53%
BenchmarkGunzip 110121663 109843648 -0.25%
BenchmarkHTTPClientServer 81930 85446 +4.29%
BenchmarkJSONEncode 24638574 24280603 -1.45%
BenchmarkJSONDecode 93022423 85753546 -7.81%
BenchmarkMandelbrot200 4703899 4735407 +0.67%
BenchmarkGoParse 5319853 5086843 -4.38%
BenchmarkRegexpMatchEasy0_32 151 151 +0.00%
BenchmarkRegexpMatchEasy0_1K 452 453 +0.22%
BenchmarkRegexpMatchEasy1_32 131 132 +0.76%
BenchmarkRegexpMatchEasy1_1K 761 722 -5.12%
BenchmarkRegexpMatchMedium_32 228 224 -1.75%
BenchmarkRegexpMatchMedium_1K 63751 64296 +0.85%
BenchmarkRegexpMatchHard_32 3188 3238 +1.57%
BenchmarkRegexpMatchHard_1K 95396 96756 +1.43%
BenchmarkRevcomp 661587262 687107364 +3.86%
BenchmarkTemplate 108312598 104008540 -3.97%
BenchmarkTimeParse 453 459 +1.32%
BenchmarkTimeFormat 475 441 -7.16%
The garbage benchmark from the benchmarks subrepo gets 2.6% faster as well.
Change-Id: I320aeda332db81012688b26ffab23f6581c59cfa
Reviewed-on: https://go-review.googlesource.com/8460
Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
diff --git a/src/cmd/internal/gc/syntax.go b/src/cmd/internal/gc/syntax.go
index 736c7af..11cdf29 100644
--- a/src/cmd/internal/gc/syntax.go
+++ b/src/cmd/internal/gc/syntax.go
@@ -304,6 +304,7 @@
ORETJMP // return to other function
OPS // compare parity set (for x86 NaN check)
OSQRT // sqrt(float64), on systems that have hw support
+ OGETG // runtime.getg() (read g pointer)
OEND
)
