MIPS64: r6 compact branch optimization.

src/mips64/constants-mips64.cc

Index: src/mips64/constants-mips64.cc
diff --git a/src/mips64/constants-mips64.cc b/src/mips64/constants-mips64.cc
index efabfe4f264c94f045386edd8a66874afd1b9380..31cc44887b8a965a009a3a7c6e5c9abc6a286c51 100644
--- a/src/mips64/constants-mips64.cc
+++ b/src/mips64/constants-mips64.cc
@@ -126,24 +126,28 @@ int FPURegisters::Number(const char* name) {
 // -----------------------------------------------------------------------------
 // Instructions.
 
-bool Instruction::IsForbiddenInBranchDelay() const {
-  const int op = OpcodeFieldRaw();
-  switch (op) {
+bool Instruction::IsForbiddenAfterBranchInstr(Instr instr) {
+  Opcode opcode = static_cast<Opcode>(instr & kOpcodeMask);
+  switch (opcode) {
     case J:
     case JAL:
     case BEQ:
     case BNE:
-    case BLEZ:
-    case BGTZ:
+    case BLEZ:  // POP06 bgeuc/bleuc, blezalc, bgezalc
+    case BGTZ:  // POP07 bltuc/bgtuc, bgtzalc, bltzalc
     case BEQL:
     case BNEL:
-    case BLEZL:
-    case BGTZL:
+    case BLEZL:  // POP26 bgezc, blezc, bgec/blec
+    case BGTZL:  // POP27 bgtzc, bltzc, bltc/bgtc
     case BC:
     case BALC:
+    case POP10:  // beqzalc, bovc, beqc
+    case POP30:  // bnezalc, bvnc, bnec

[balazs.kilvady, 2015/12/18 19:18:05]

I mistyped again, please: s/bvnc/bnvc

[ivica.bogosavljevic, 2015/12/22 10:22:39]

Acknowledged.

+    case POP66:  // beqzc, jic
+    case POP76:  // bnezc, jialc
       return true;
     case REGIMM:
-      switch (RtFieldRaw()) {
+      switch (instr & kRtFieldMask) {
         case BLTZ:
         case BGEZ:
         case BLTZAL:
@@ -154,7 +158,7 @@ bool Instruction::IsForbiddenInBranchDelay() const {
       }
       break;
     case SPECIAL:
-      switch (FunctionFieldRaw()) {
+      switch (instr & kFunctionFieldMask) {
         case JR:
         case JALR:
           return true;
@@ -162,6 +166,17 @@ bool Instruction::IsForbiddenInBranchDelay() const {
           return false;
       }
       break;
+    case COP1:
+      switch (instr & kRsFieldMask) {
+        case BC1:
+        case BC1EQZ:
+        case BC1NEZ:
+          return true;
+          break;
+        default:
+          return false;
+      }
+      break;
     default:
       return false;
   }
@@ -169,8 +184,7 @@ bool Instruction::IsForbiddenInBranchDelay() const {
 
 
 bool Instruction::IsLinkingInstruction() const {
-  const int op = OpcodeFieldRaw();
-  switch (op) {
+  switch (OpcodeFieldRaw()) {
     case JAL:
       return true;
     case POP76: