[X86] Merge the different Jcc instructions for each condition code into single instructions that store the condition code as an operand.

Summary:
This avoids needing an isel pattern for each condition code. And it removes translation switches for converting between Jcc instructions and condition codes.

Now the printer, encoder and disassembler take care of converting the immediate. We use InstAliases to handle the assembly matching. But we print using the asm string in the instruction definition. The instruction itself is marked IsCodeGenOnly=1 to hide it from the assembly parser.

Reviewers: spatel, lebedev.ri, courbet, gchatelet, RKSimon

Reviewed By: RKSimon

Subscribers: MatzeB, qcolombet, eraman, hiraditya, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60228

llvm-svn: 357802

1 files changed, 7 insertions, 9 deletions

diff --git a/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp b/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp
index 6cf01c988d7..1b541390ce0 100644
--- a/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp
+++ b/llvm/lib/Target/X86/X86FlagsCopyLowering.cpp
@@ -251,13 +251,13 @@ static MachineBasicBlock &splitBlock(MachineBasicBlock &MBB,
          "Split instruction must be in the split block!");
   assert(SplitI.isBranch() &&
          "Only designed to split a tail of branch instructions!");
-  assert(X86::getCondFromBranchOpc(SplitI.getOpcode()) != X86::COND_INVALID &&
+  assert(X86::getCondFromBranch(SplitI) != X86::COND_INVALID &&
          "Must split on an actual jCC instruction!");
 
   // Dig out the previous instruction to the split point.
   MachineInstr &PrevI = *std::prev(SplitI.getIterator());
   assert(PrevI.isBranch() && "Must split after a branch!");
-  assert(X86::getCondFromBranchOpc(PrevI.getOpcode()) != X86::COND_INVALID &&
+  assert(X86::getCondFromBranch(PrevI) != X86::COND_INVALID &&
          "Must split after an actual jCC instruction!");
   assert(!std::prev(PrevI.getIterator())->isTerminator() &&
          "Must only have this one terminator prior to the split!");
@@ -587,13 +587,13 @@ bool X86FlagsCopyLoweringPass::runOnMachineFunction(MachineFunction &MF) {
         // branch folding or black placement. As a consequence, we get to deal
         // with the simpler formulation of conditional branches followed by tail
         // calls.
-        if (X86::getCondFromBranchOpc(MI.getOpcode()) != X86::COND_INVALID) {
+        if (X86::getCondFromBranch(MI) != X86::COND_INVALID) {
           auto JmpIt = MI.getIterator();
           do {
             JmpIs.push_back(&*JmpIt);
             ++JmpIt;
           } while (JmpIt != UseMBB.instr_end() &&
-                   X86::getCondFromBranchOpc(JmpIt->getOpcode()) !=
+                   X86::getCondFromBranch(*JmpIt) !=
                        X86::COND_INVALID);
           break;
         }
@@ -863,7 +863,7 @@ void X86FlagsCopyLoweringPass::rewriteCondJmp(
     MachineBasicBlock &TestMBB, MachineBasicBlock::iterator TestPos,
     DebugLoc TestLoc, MachineInstr &JmpI, CondRegArray &CondRegs) {
   // First get the register containing this specific condition.
-  X86::CondCode Cond = X86::getCondFromBranchOpc(JmpI.getOpcode());
+  X86::CondCode Cond = X86::getCondFromBranch(JmpI);
   unsigned CondReg;
   bool Inverted;
   std::tie(CondReg, Inverted) =
@@ -876,10 +876,8 @@ void X86FlagsCopyLoweringPass::rewriteCondJmp(
 
   // Rewrite the jump to use the !ZF flag from the test, and kill its use of
   // flags afterward.
-  JmpI.setDesc(TII->get(
-      X86::GetCondBranchFromCond(Inverted ? X86::COND_E : X86::COND_NE)));
-  const int ImplicitEFLAGSOpIdx = 1;
-  JmpI.getOperand(ImplicitEFLAGSOpIdx).setIsKill(true);
+  JmpI.getOperand(1).setImm(Inverted ? X86::COND_E : X86::COND_NE);
+  JmpI.findRegisterUseOperand(X86::EFLAGS)->setIsKill(true);
   LLVM_DEBUG(dbgs() << "    fixed jCC: "; JmpI.dump());
 }