From 6548b63d6b5151a5063c92d4cffc7d861dfa0ed9 Mon Sep 17 00:00:00 2001 From: Josh Bleecher Snyder Date: Wed, 5 Aug 2015 16:11:57 -0700 Subject: [PATCH] [dev.ssa] cmd/compile: don't move OpSP and OpSB values regalloc expects to find all OpSP and OpSB values in the entry block. There is no value to moving them; don't. Change-Id: I775198f03ce7420348721ffc5e7d2bab065465b1 Reviewed-on: https://go-review.googlesource.com/13266 Reviewed-by: Keith Randall --- src/cmd/compile/internal/ssa/regalloc.go | 3 ++- src/cmd/compile/internal/ssa/tighten.go | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index dac107dd18..9056531634 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -101,7 +101,8 @@ func regalloc(f *Func) { var oldSched []*Value - // Hack to find sp and sb Values and assign them a register. (TODO: make not so hacky) + // Hack to find sp and sb Values and assign them a register. + // TODO: make not so hacky; update the tighten pass when this is done var sp, sb *Value for _, v := range f.Entry.Values { switch v.Op { diff --git a/src/cmd/compile/internal/ssa/tighten.go b/src/cmd/compile/internal/ssa/tighten.go index a43218095e..02b1f701f5 100644 --- a/src/cmd/compile/internal/ssa/tighten.go +++ b/src/cmd/compile/internal/ssa/tighten.go @@ -57,6 +57,13 @@ func tighten(f *Func) { if v.Op == OpPhi { continue } + if v.Op == OpSB || v.Op == OpSP { + // regalloc expects OpSP and OpSB values to be in the entry block, + // so don't move them. + // TODO: Handle this more gracefully in regalloc and + // remove this restriction. + continue + } if uses[v.ID] == 1 && !phi[v.ID] && home[v.ID] != b && len(v.Args) < 2 { // v is used in exactly one block, and it is not b. // Furthermore, it takes at most one input,