Rename canUseAsImmediateForOpcode to getImmediateForOpcode to better

  indicate that it is not a boolean function.
Properly emit the pseudo instruction for conditional branch, so that we
  can fix up conditional branches whose displacements are too large.
Reserve the right amount of opcode space for said pseudo instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21094 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPC32ISelSimple.cpp b/lib/Target/PowerPC/PPC32ISelSimple.cpp
index 78d16885c04933c3377ba2ac406047650c3bf862..80c554c824a8783ec5f0d1c6c5f8f82eea077a63 100644 (file)
--- a/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -1585,11 +1585,11 @@ void PPC32ISel::visitBranchInst(BranchInst &BI) {
       .addImm(0);
     if (BI.getSuccessor(1) == NextBB) {
       if (BI.getSuccessor(0) != NextBB)
-        BuildMI(BB, PPC::COND_BRANCH, 3).addReg(PPC::CR0).addImm(PPC::BNE)
+        BuildMI(BB, PPC::COND_BRANCH, 4).addReg(PPC::CR0).addImm(PPC::BNE)
           .addMBB(MBBMap[BI.getSuccessor(0)])
           .addMBB(MBBMap[BI.getSuccessor(1)]);
     } else {
-      BuildMI(BB, PPC::COND_BRANCH, 3).addReg(PPC::CR0).addImm(PPC::BEQ)
+      BuildMI(BB, PPC::COND_BRANCH, 4).addReg(PPC::CR0).addImm(PPC::BEQ)
         .addMBB(MBBMap[BI.getSuccessor(1)])
         .addMBB(MBBMap[BI.getSuccessor(0)]);
       if (BI.getSuccessor(0) != NextBB)
@@ -1604,7 +1604,7 @@ void PPC32ISel::visitBranchInst(BranchInst &BI) {
   OpNum = EmitComparison(OpNum, SCI->getOperand(0), SCI->getOperand(1), BB,MII);
   
   if (BI.getSuccessor(0) != NextBB) {
-    BuildMI(BB, PPC::COND_BRANCH, 3).addReg(PPC::CR0).addImm(Opcode)
+    BuildMI(BB, PPC::COND_BRANCH, 4).addReg(PPC::CR0).addImm(Opcode)
       .addMBB(MBBMap[BI.getSuccessor(0)])
       .addMBB(MBBMap[BI.getSuccessor(1)]);
     if (BI.getSuccessor(1) != NextBB)
@@ -1613,7 +1613,7 @@ void PPC32ISel::visitBranchInst(BranchInst &BI) {
     // Change to the inverse condition...
     if (BI.getSuccessor(1) != NextBB) {
       Opcode = PPC32InstrInfo::invertPPCBranchOpcode(Opcode);
-      BuildMI(BB, PPC::COND_BRANCH, 3).addReg(PPC::CR0).addImm(Opcode)
+      BuildMI(BB, PPC::COND_BRANCH, 4).addReg(PPC::CR0).addImm(Opcode)
         .addMBB(MBBMap[BI.getSuccessor(1)])
         .addMBB(MBBMap[BI.getSuccessor(0)]);
     }

diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 3b599c580ef04035395a61b345948f7be56e98f7..f480ed21eb66d0bc6eae12ce0bba69165da8210d 100644 (file)
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -497,17 +497,17 @@ static unsigned ExactLog2(unsigned Val) {
   return Count;
 }
 
-/// canUseAsImmediateForOpcode - This method returns a value indicating whether
+/// getImmediateForOpcode - This method returns a value indicating whether
 /// the ConstantSDNode N can be used as an immediate to Opcode.  The return
 /// values are either 0, 1 or 2.  0 indicates that either N is not a
 /// ConstantSDNode, or is not suitable for use by that opcode.  A return value 
 /// of 1 indicates that the constant may be used in normal immediate form.  A
 /// return value of 2 indicates that the constant may be used in shifted
-/// immediate form.  If the return value is nonzero, the constant value is
-/// placed in Imm.
+/// immediate form.  A return value of 3 indicates that log base 2 of the
+/// constant may be used.
 ///
-static unsigned canUseAsImmediateForOpcode(SDOperand N, unsigned Opcode,
-                                           unsigned& Imm, bool U = false) {
+static unsigned getImmediateForOpcode(SDOperand N, unsigned Opcode,
+                                      unsigned& Imm, bool U = false) {
   if (N.getOpcode() != ISD::Constant) return 0;
 
   int v = (int)cast<ConstantSDNode>(N)->getSignExtended();
@@ -533,7 +533,7 @@ static unsigned canUseAsImmediateForOpcode(SDOperand N, unsigned Opcode,
     if (!U && (v <= 32767 && v >= -32768)) { Imm = v & 0xFFFF; return 1; }
     break;
   case ISD::SDIV:
-    if (0 != ExactLog2(v)) { Imm = ExactLog2(v); return 1; }
+    if ((Imm = ExactLog2(v))) { return 3; }
     break;
   }
   return 0;
@@ -619,10 +619,10 @@ unsigned ISel::SelectSetCR0(SDOperand CC) {
     Opc = getBCCForSetCC(SetCC->getCondition(), U);
     Tmp1 = SelectExpr(SetCC->getOperand(0));
 
-    // Pass the optional argument U to canUseAsImmediateForOpcode for SETCC,
+    // Pass the optional argument U to getImmediateForOpcode for SETCC,
     // so that it knows whether the SETCC immediate range is signed or not.
-    if (1 == canUseAsImmediateForOpcode(SetCC->getOperand(1), ISD::SETCC, 
-                                        Tmp2, U)) {
+    if (1 == getImmediateForOpcode(SetCC->getOperand(1), ISD::SETCC, 
+                                   Tmp2, U)) {
       if (U)
         BuildMI(BB, PPC::CMPLWI, 2, PPC::CR0).addReg(Tmp1).addImm(Tmp2);
       else
@@ -647,7 +647,7 @@ bool ISel::SelectAddr(SDOperand N, unsigned& Reg, int& offset)
   unsigned imm = 0, opcode = N.getOpcode();
   if (N.getOpcode() == ISD::ADD) {
     Reg = SelectExpr(N.getOperand(0));
-    if (1 == canUseAsImmediateForOpcode(N.getOperand(1), opcode, imm)) {
+    if (1 == getImmediateForOpcode(N.getOperand(1), opcode, imm)) {
       offset = imm;
       return false;
     } 
@@ -665,9 +665,15 @@ void ISel::SelectBranchCC(SDOperand N)
   MachineBasicBlock *Dest = 
     cast<BasicBlockSDNode>(N.getOperand(2))->getBasicBlock();
 
+  // Get the MBB we will fall through to so that we can hand it off to the
+  // branch selection pass as an argument to the PPC::COND_BRANCH pseudo op.
+  ilist<MachineBasicBlock>::iterator It = BB;
+  MachineBasicBlock *Fallthrough = ++It;
+  
   Select(N.getOperand(0));  //chain
   unsigned Opc = SelectSetCR0(N.getOperand(1));
-  BuildMI(BB, Opc, 2).addReg(PPC::CR0).addMBB(Dest);
+  BuildMI(BB, PPC::COND_BRANCH, 4).addReg(PPC::CR0).addImm(Opc)
+    .addMBB(Dest).addMBB(Fallthrough);
   return;
 }
 
@@ -1285,7 +1291,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
   case ISD::ADD:
     assert (DestType == MVT::i32 && "Only do arithmetic on i32s!");
     Tmp1 = SelectExpr(N.getOperand(0));
-    switch(canUseAsImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
+    switch(getImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
       default: assert(0 && "unhandled result code");
       case 0: // No immediate
         Tmp2 = SelectExpr(N.getOperand(1));
@@ -1303,7 +1309,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
   case ISD::AND:
   case ISD::OR:
     Tmp1 = SelectExpr(N.getOperand(0));
-    switch(canUseAsImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
+    switch(getImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
       default: assert(0 && "unhandled result code");
       case 0: // No immediate
         Tmp2 = SelectExpr(N.getOperand(1));
@@ -1364,7 +1370,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
       return Result;
     }
     Tmp1 = SelectExpr(N.getOperand(0));
-    switch(canUseAsImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
+    switch(getImmediateForOpcode(N.getOperand(1), opcode, Tmp2)) {
       default: assert(0 && "unhandled result code");
       case 0: // No immediate
         Tmp2 = SelectExpr(N.getOperand(1));
@@ -1382,7 +1388,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
 
   case ISD::SUB:
     Tmp2 = SelectExpr(N.getOperand(1));
-    if (1 == canUseAsImmediateForOpcode(N.getOperand(0), opcode, Tmp1))
+    if (1 == getImmediateForOpcode(N.getOperand(0), opcode, Tmp1))
       BuildMI(BB, PPC::SUBFIC, 2, Result).addReg(Tmp2).addSImm(Tmp1);
     else {
       Tmp1 = SelectExpr(N.getOperand(0));
@@ -1392,7 +1398,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
     
   case ISD::MUL:
     Tmp1 = SelectExpr(N.getOperand(0));
-    if (1 == canUseAsImmediateForOpcode(N.getOperand(1), opcode, Tmp2))
+    if (1 == getImmediateForOpcode(N.getOperand(1), opcode, Tmp2))
       BuildMI(BB, PPC::MULLI, 2, Result).addReg(Tmp1).addSImm(Tmp2);
     else {
       Tmp2 = SelectExpr(N.getOperand(1));
@@ -1402,7 +1408,7 @@ unsigned ISel::SelectExpr(SDOperand N) {
 
   case ISD::SDIV:
   case ISD::UDIV:
-    if (1 == canUseAsImmediateForOpcode(N.getOperand(1), opcode, Tmp3)) {
+    if (3 == getImmediateForOpcode(N.getOperand(1), opcode, Tmp3)) {
       Tmp1 = MakeReg(MVT::i32);
       Tmp2 = SelectExpr(N.getOperand(0));
       BuildMI(BB, PPC::SRAWI, 2, Tmp1).addReg(Tmp2).addImm(Tmp3);