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| author | Keith Randall <khr@google.com> | 2018-01-22 09:43:27 -0800 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2018-08-09 21:44:22 +0000 |
| commit | dea961ebd9f871b39b3bdaab32f952037f28cd71 (patch) | |
| tree | 11732f9ab254aea890b2733c3057fd87fecebaa9 | |
| parent | b8ae3569c8aa8cb8d569f2941939e30c3d342444 (diff) | |
| download | go-dea961ebd9f871b39b3bdaab32f952037f28cd71.tar.gz go-dea961ebd9f871b39b3bdaab32f952037f28cd71.zip | |
[release-branch.go1.10] cmd/compile: reset branch prediction when deleting a branch
When we go from a branch block to a plain block, reset the
branch prediction bit. Downstream passes asssume that if the
branch prediction is set, then the block has 2 successors.
Fixes #23504
Fixes #26851
Change-Id: I2898ec002228b2e34fe80ce420c6939201c0a5aa
Reviewed-on: https://go-review.googlesource.com/88955
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
(cherry picked from commit 4313d7767d830e863e8f8b53a2b48ca8d0bf0a79)
Reviewed-on: https://go-review.googlesource.com/128855
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
| -rw-r--r-- | src/cmd/compile/internal/ssa/check.go | 2 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/fuse.go | 1 | ||||
| -rw-r--r-- | test/fixedbugs/issue23504.go | 15 |
3 files changed, 17 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/ssa/check.go b/src/cmd/compile/internal/ssa/check.go index 1c2fcd7948..f2d7c9e220 100644 --- a/src/cmd/compile/internal/ssa/check.go +++ b/src/cmd/compile/internal/ssa/check.go @@ -102,7 +102,7 @@ func checkFunc(f *Func) { f.Fatalf("plain/dead block %s has a control value", b) } } - if len(b.Succs) > 2 && b.Likely != BranchUnknown { + if len(b.Succs) != 2 && b.Likely != BranchUnknown { f.Fatalf("likeliness prediction %d for block %s with %d successors", b.Likely, b, len(b.Succs)) } diff --git a/src/cmd/compile/internal/ssa/fuse.go b/src/cmd/compile/internal/ssa/fuse.go index f00356a7b2..45b13a050d 100644 --- a/src/cmd/compile/internal/ssa/fuse.go +++ b/src/cmd/compile/internal/ssa/fuse.go @@ -92,6 +92,7 @@ func fuseBlockIf(b *Block) bool { b.removeEdge(1) } b.Kind = BlockPlain + b.Likely = BranchUnknown b.SetControl(nil) // Trash the empty blocks s0 & s1. diff --git a/test/fixedbugs/issue23504.go b/test/fixedbugs/issue23504.go new file mode 100644 index 0000000000..77f3184149 --- /dev/null +++ b/test/fixedbugs/issue23504.go @@ -0,0 +1,15 @@ +// compile + +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package p + +func f() { + var B bool + B2 := (B || B && !B) && !B + B3 := B2 || B + for (B3 || B2) && !B2 && B { + } +} |