From 08a87938bb95ae8859600be20a998fbb4b904915 Mon Sep 17 00:00:00 2001 From: David Chase Date: Mon, 30 Sep 2019 11:10:36 -0400 Subject: [PATCH] cmd/compile: make nilcheck more careful about statement relocations The earlier code was picking nodes that were "poor choices" and thus sometimes losing statements altogether. Change-Id: Ibe5ed800ffbd3c926c0ab1bc10c77d72d3042e45 Reviewed-on: https://go-review.googlesource.com/c/go/+/198478 Run-TryBot: David Chase Reviewed-by: Jeremy Faller --- src/cmd/compile/internal/ssa/nilcheck.go | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/ssa/nilcheck.go b/src/cmd/compile/internal/ssa/nilcheck.go index 009c68afa1..9516d58a6e 100644 --- a/src/cmd/compile/internal/ssa/nilcheck.go +++ b/src/cmd/compile/internal/ssa/nilcheck.go @@ -153,12 +153,20 @@ func nilcheckelim(f *Func) { work = append(work, bp{op: ClearPtr, ptr: ptr}) fallthrough // a non-eliminated nil check might be a good place for a statement boundary. default: - if pendingLines.contains(v.Pos) && v.Pos.IsStmt() != src.PosNotStmt { + if v.Pos.IsStmt() != src.PosNotStmt && !isPoorStatementOp(v.Op) && pendingLines.contains(v.Pos) { v.Pos = v.Pos.WithIsStmt() pendingLines.remove(v.Pos) } } } + // This reduces the lost statement count in "go" by 5 (out of 500 total). + for j := 0; j < i; j++ { // is this an ordering problem? + v := b.Values[j] + if v.Pos.IsStmt() != src.PosNotStmt && !isPoorStatementOp(v.Op) && pendingLines.contains(v.Pos) { + v.Pos = v.Pos.WithIsStmt() + pendingLines.remove(v.Pos) + } + } if pendingLines.contains(b.Pos) { b.Pos = b.Pos.WithIsStmt() pendingLines.remove(b.Pos)