diff options
Diffstat (limited to 'src/cmd/compile/internal/ssa/expand_calls.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/expand_calls.go | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go index 79434f33d3..a0f0e653aa 100644 --- a/src/cmd/compile/internal/ssa/expand_calls.go +++ b/src/cmd/compile/internal/ssa/expand_calls.go @@ -1098,6 +1098,17 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) { if a.MemoryArg() != m0 { x.f.Fatalf("Op...LECall and OpDereference have mismatched mem, %s and %s", v.LongString(), a.LongString()) } + if v.Op == OpTailLECall { + // It's common for a tail call passing the same arguments (e.g. method wrapper), + // so this would be a self copy. Detect this and optimize it out. + a0 := a.Args[0] + if a0.Op == OpLocalAddr { + n := a0.Aux.(*ir.Name) + if n.Class == ir.PPARAM && n.FrameOffset()+x.f.Config.ctxt.FixedFrameSize() == aOffset { + continue + } + } + } // "Dereference" of addressed (probably not-SSA-eligible) value becomes Move // TODO(register args) this will be more complicated with registers in the picture. mem = x.rewriteDereference(v.Block, sp, a, mem, aOffset, aux.SizeOfArg(auxI), aType, a.Pos) @@ -1110,6 +1121,14 @@ func (x *expandState) rewriteArgs(v *Value, firstArg int) { } else { aOffset = aux.OffsetOfArg(auxI) } + if v.Op == OpTailLECall && a.Op == OpArg && a.AuxInt == 0 { + // It's common for a tail call passing the same arguments (e.g. method wrapper), + // so this would be a self copy. Detect this and optimize it out. + n := a.Aux.(*ir.Name) + if n.Class == ir.PPARAM && n.FrameOffset()+x.f.Config.ctxt.FixedFrameSize() == aOffset { + continue + } + } if x.debug > 1 { x.Printf("...storeArg %s, %v, %d\n", a.LongString(), aType, aOffset) } |