[dev.ssa] Merge remote-tracking branch 'origin/master' into mergebranch

Semi-regular merge of tip to dev.ssa.

Complicated a bit by the move of cmd/internal/* to cmd/compile/internal/*.

Change-Id: I1c66d3c29bb95cce4a53c5a3476373aa5245303d

1 files changed, 112 insertions, 0 deletions

diff --git a/src/cmd/compile/internal/ssa/lower.go b/src/cmd/compile/internal/ssa/lower.go
new file mode 100644
index 0000000000..44f0b83fa8
--- /dev/null
+++ b/src/cmd/compile/internal/ssa/lower.go
@@ -0,0 +1,112 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssa
+
+import "log"
+
+//go:generate go run rulegen/rulegen.go rulegen/lower_amd64.rules lowerAmd64 lowerAmd64.go
+
+// convert to machine-dependent ops
+func lower(f *Func) {
+	// repeat rewrites until we find no more rewrites
+	applyRewrite(f, f.Config.lower)
+
+	// Check for unlowered opcodes, fail if we find one.
+	for _, b := range f.Blocks {
+		for _, v := range b.Values {
+			if v.Op < OpGenericEnd && v.Op != OpFP && v.Op != OpSP && v.Op != OpArg && v.Op != OpCopy && v.Op != OpPhi {
+				log.Panicf("%s not lowered", v.LongString())
+			}
+		}
+	}
+
+	// additional pass for 386/amd64, link condition codes directly to blocks
+	// TODO: do generically somehow?  Special "block" rewrite rules?
+	for _, b := range f.Blocks {
+		for {
+			switch b.Kind {
+			case BlockIf:
+				switch b.Control.Op {
+				case OpSETL:
+					b.Kind = BlockLT
+					b.Control = b.Control.Args[0]
+					continue
+				case OpSETNE:
+					b.Kind = BlockNE
+					b.Control = b.Control.Args[0]
+					continue
+				case OpSETB:
+					b.Kind = BlockULT
+					b.Control = b.Control.Args[0]
+					continue
+				case OpMOVBload:
+					b.Kind = BlockNE
+					b.Control = b.NewValue2(OpTESTB, TypeFlags, nil, b.Control, b.Control)
+					continue
+					// TODO: others
+				}
+			case BlockLT:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockGT
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockGT:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockLT
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockLE:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockGE
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockGE:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockLE
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockULT:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockUGT
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockUGT:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockULT
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockULE:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockUGE
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockUGE:
+				if b.Control.Op == OpInvertFlags {
+					b.Kind = BlockULE
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockEQ:
+				if b.Control.Op == OpInvertFlags {
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			case BlockNE:
+				if b.Control.Op == OpInvertFlags {
+					b.Control = b.Control.Args[0]
+					continue
+				}
+			}
+			break
+		}
+	}
+}