diff options
author | Cherry Zhang <cherryyz@google.com> | 2016-08-17 13:29:19 -0400 |
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committer | Cherry Zhang <cherryyz@google.com> | 2016-08-17 21:03:26 +0000 |
commit | 3d5cf72ca9beaedc5dcc8b094945de95fa35a670 (patch) | |
tree | 0e8f9bf57a432aa0a3833e979679280820fed7c7 /src/cmd/compile/internal/ssa/cse.go | |
parent | 2b8e143dc302d2f3817cb3df1c1cc0b2cde3bbc1 (diff) | |
download | go-3d5cf72ca9beaedc5dcc8b094945de95fa35a670.tar.gz go-3d5cf72ca9beaedc5dcc8b094945de95fa35a670.zip |
cmd/compile: CSE copied tuple selectors
In CSE if a tuple generator is CSE'd to a different block, its
selectors are copied to the same block. In this case, also CES
the copied selectors.
Test copied from Keith's CL 27202.
Fixes #16741.
Change-Id: I2fc8b9513d430f10d6104275cfff5fb75d3ef3d9
Reviewed-on: https://go-review.googlesource.com/27236
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa/cse.go')
-rw-r--r-- | src/cmd/compile/internal/ssa/cse.go | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/cse.go b/src/cmd/compile/internal/ssa/cse.go index a000c577d1..c0ddc83681 100644 --- a/src/cmd/compile/internal/ssa/cse.go +++ b/src/cmd/compile/internal/ssa/cse.go @@ -166,7 +166,10 @@ func cse(f *Func) { // if we rewrite a tuple generator to a new one in a different block, // copy its selectors to the new generator's block, so tuple generator // and selectors stay together. + // be careful not to copy same selectors more than once (issue 16741). + copiedSelects := make(map[ID][]*Value) for _, b := range f.Blocks { + out: for _, v := range b.Values { if rewrite[v.ID] != nil { continue @@ -180,8 +183,16 @@ func cse(f *Func) { t := rewrite[v.Args[0].ID] if t != nil && t.Block != b { // v.Args[0] is tuple generator, CSE'd into a different block as t, v is left behind + for _, c := range copiedSelects[t.ID] { + if v.Op == c.Op { + // an equivalent selector is already copied + rewrite[v.ID] = c + continue out + } + } c := v.copyInto(t.Block) rewrite[v.ID] = c + copiedSelects[t.ID] = append(copiedSelects[t.ID], c) } } } |