diff options
| author | Cherry Zhang <cherryyz@google.com> | 2017-03-14 18:21:23 -0400 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2017-03-14 22:55:52 +0000 |
| commit | 8a44c8efaefbbda6dd7ab4ee9a5e449fefbf5e1a (patch) | |
| tree | 08ec3c066e1c4fd5c33423850af652f57cd0c291 /src/cmd/compile/internal/ssa/regalloc.go | |
| parent | 2d78538c12ed63cc931b552c9c98b7c93b91b21d (diff) | |
| download | go-8a44c8efaefbbda6dd7ab4ee9a5e449fefbf5e1a.tar.xz | |
cmd/compile: don't spill rematerializeable value when resolving merge edges
Fixes #19515.
Change-Id: I4bcce152cef52d00fbb5ab4daf72a6e742bae27c
Reviewed-on: https://go-review.googlesource.com/38158
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa/regalloc.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/regalloc.go | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index aac950a76b..e40fe17ad4 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -2227,6 +2227,7 @@ func (e *edgeState) findRegFor(typ Type) Location { // 1) an unused register // 2) a non-unique register not holding a final value // 3) a non-unique register + // 4) TODO: a register holding a rematerializeable value x := m &^ e.usedRegs if x != 0 { return &e.s.registers[pickReg(x)] @@ -2252,10 +2253,12 @@ func (e *edgeState) findRegFor(typ Type) Location { a := e.cache[vid] for _, c := range a { if r, ok := e.s.f.getHome(c.ID).(*Register); ok && m>>uint(r.num)&1 != 0 { - x := e.p.NewValue1(c.Pos, OpStoreReg, c.Type, c) - e.set(t, vid, x, false, c.Pos) - if e.s.f.pass.debug > regDebug { - fmt.Printf(" SPILL %s->%s %s\n", r.Name(), t.Name(), x.LongString()) + if !c.rematerializeable() { + x := e.p.NewValue1(c.Pos, OpStoreReg, c.Type, c) + e.set(t, vid, x, false, c.Pos) + if e.s.f.pass.debug > regDebug { + fmt.Printf(" SPILL %s->%s %s\n", r.Name(), t.Name(), x.LongString()) + } } // r will now be overwritten by the caller. At some point // later, the newly saved value will be moved back to its |