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This change makes compiler frontend dead code elimination of const expr if statements introduced in https://golang.org/cl/38773 treat both if constCondTrue { ...; returnStmt } toBeRemoved... if constCondFalse { ...; } else { returnStmt } toBeRemoved... identically to: if constCondTrue { ...; returnStmt } else { toBeRemoved... } Where "constCondTrue" is a an expression that can be evaluated to "true" during compile time. The additional checks are only triggered for const expr if conditions that evaluate to true. name old time/op new time/op delta Template 431ms ± 2% 429ms ± 1% ~ (p=0.491 n=8+6) Unicode 198ms ± 4% 201ms ± 2% ~ (p=0.234 n=7+6) GoTypes 1.40s ± 1% 1.41s ± 2% ~ (p=0.053 n=7+7) Compiler 6.72s ± 2% 6.81s ± 1% +1.35% (p=0.011 n=7+7) SSA 17.3s ± 1% 17.3s ± 2% ~ (p=0.731 n=6+7) Flate 275ms ± 2% 275ms ± 2% ~ (p=0.902 n=7+7) GoParser 340ms ± 2% 339ms ± 2% ~ (p=0.902 n=7+7) Reflect 910ms ± 2% 905ms ± 1% ~ (p=0.310 n=6+6) Tar 403ms ± 1% 403ms ± 2% ~ (p=0.366 n=7+6) XML 486ms ± 1% 490ms ± 1% ~ (p=0.065 n=6+6) StdCmd 56.2s ± 1% 56.6s ± 2% ~ (p=0.620 n=7+7) name old user-time/op new user-time/op delta Template 559ms ± 8% 557ms ± 7% ~ (p=0.713 n=8+7) Unicode 266ms ±13% 277ms ± 9% ~ (p=0.157 n=8+7) GoTypes 1.83s ± 2% 1.84s ± 1% ~ (p=0.522 n=8+7) Compiler 8.67s ± 4% 8.89s ± 4% ~ (p=0.077 n=7+7) SSA 23.9s ± 1% 24.2s ± 1% +1.31% (p=0.005 n=7+7) Flate 351ms ± 4% 342ms ± 5% ~ (p=0.105 n=7+7) GoParser 437ms ± 2% 423ms ± 5% -3.14% (p=0.016 n=7+7) Reflect 1.16s ± 3% 1.15s ± 2% ~ (p=0.362 n=7+7) Tar 517ms ± 4% 511ms ± 3% ~ (p=0.538 n=7+7) XML 619ms ± 3% 617ms ± 4% ~ (p=0.483 n=7+7) Fixes #23521 Change-Id: I165a7827d869aeb93ce6047d026ff873d039a4f3 Reviewed-on: https://go-review.googlesource.com/91056 Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
44 lines
773 B
Go
44 lines
773 B
Go
// errorcheck -0 -m
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Issue 23521: improve early DCE for if without explicit else.
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package p
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//go:noinline
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func nonleaf() {}
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const truth = true
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func f() int { // ERROR "can inline f"
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if truth {
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return 0
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}
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// If everything below is removed, as it should,
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// function f should be inlineable.
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nonleaf()
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for {
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panic("")
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}
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}
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func g() int { // ERROR "can inline g"
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return f() // ERROR "inlining call to f"
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}
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func f2() int { // ERROR "can inline f2"
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if !truth {
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nonleaf()
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} else {
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return 0
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}
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panic("")
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}
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func g2() int { // ERROR "can inline g2"
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return f2() // ERROR "inlining call to f2"
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}
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