diff options
Diffstat (limited to 'src/cmd/compile/internal/ssa/regalloc.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/regalloc.go | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/regalloc.go b/src/cmd/compile/internal/ssa/regalloc.go index 8309af2997..4180868932 100644 --- a/src/cmd/compile/internal/ssa/regalloc.go +++ b/src/cmd/compile/internal/ssa/regalloc.go @@ -460,6 +460,18 @@ func (s *regAllocState) allocValToReg(v *Value, mask regMask, nospill bool, line return c } +// isLeaf reports whether f performs any calls. +func isLeaf(f *Func) bool { + for _, b := range f.Blocks { + for _, v := range b.Values { + if opcodeTable[v.Op].call { + return false + } + } + } + return true +} + func (s *regAllocState) init(f *Func) { s.f = f s.registers = f.Config.registers @@ -510,6 +522,12 @@ func (s *regAllocState) init(f *Func) { s.allocatable &^= 1 << 12 // R12 } } + if s.f.Config.LinkReg != -1 { + if isLeaf(f) { + // Leaf functions don't save/restore the link register. + s.allocatable &^= 1 << uint(s.f.Config.LinkReg) + } + } if s.f.Config.ctxt.Flag_dynlink { switch s.f.Config.arch { case "amd64": |