[dev.ssa] Merge branch 'master' into dev.ssa

Change-Id: Iabc80b6e0734efbd234d998271e110d2eaad41dd

diff --cc src/cmd/compile/internal/gc/ssa.go
Simple merge

diff --cc src/cmd/compile/internal/ssa/config.go
index 26f16bae580b3dc9fa351c2f10e372ca150cd936,e8ab17806c0e151b64ae71779028b1cd83a3a4ac..ddb58d9f79b92c166a2fd2ad221401927d2ab839
--- 1/src/cmd/compile/internal/ssa/config.go
--- 2/src/cmd/compile/internal/ssa/config.go
+++ b/src/cmd/compile/internal/ssa/config.go
@@@ -13,19 -14,19 +14,20 @@@ import 
  )
  
  type Config struct {
-       arch         string                     // "amd64", etc.
-       IntSize      int64                      // 4 or 8
-       PtrSize      int64                      // 4 or 8
-       lowerBlock   func(*Block) bool          // lowering function
-       lowerValue   func(*Value, *Config) bool // lowering function
-       registers    []Register                 // machine registers
-       flagRegMask  regMask                    // flag register mask
-       fe           Frontend                   // callbacks into compiler frontend
-       HTML         *HTMLWriter                // html writer, for debugging
-       ctxt         *obj.Link                  // Generic arch information
-       optimize     bool                       // Do optimization
-       noDuffDevice bool                       // Don't use Duff's device
-       curFunc      *Func
+       arch            string                     // "amd64", etc.
+       IntSize         int64                      // 4 or 8
+       PtrSize         int64                      // 4 or 8
+       lowerBlock      func(*Block) bool          // lowering function
+       lowerValue      func(*Value, *Config) bool // lowering function
+       registers       []Register                 // machine registers
++      flagRegMask     regMask                    // flag register mask
+       fe              Frontend                   // callbacks into compiler frontend
+       HTML            *HTMLWriter                // html writer, for debugging
+       ctxt            *obj.Link                  // Generic arch information
+       optimize        bool                       // Do optimization
+       noDuffDevice    bool                       // Don't use Duff's device
+       sparsePhiCutoff uint64                     // Sparse phi location algorithm used above this #blocks*#variables score
+       curFunc         *Func
  
        // TODO: more stuff. Compiler flags of interest, ...
  

diff --cc src/cmd/compile/internal/ssa/gen/genericOps.go
Simple merge

diff --cc src/cmd/compile/internal/ssa/opGen.go
Simple merge

diff --cc src/cmd/compile/internal/ssa/regalloc.go
Simple merge

diff --cc src/runtime/mgc.go
Simple merge

diff --cc src/runtime/runtime1.go
Simple merge