[x86] Remove the 2-addr-to-3-addr "optimization" from shufps to pshufd.

This trades a (register-renamer-friendly) movaps for a floating point
/ integer domain cross. That is a very bad trade, even on architectures
where domain crossing is relatively fast. On any chip where there is
even a cycle stall, this is a Very Bad Idea. It doesn't even seem likely
to cause a spill to be introduced because the reason for the copy is to
destructively shuffle in place.

Thanks to Ben Kramer for fixing a bug in this code that my new shuffle
lowering exposed and highlighting that perhaps it should just go away.
=]

llvm-svn: 219090

1 files changed, 0 insertions, 28 deletions

diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp
index dc97185ed95..a7637f9e65d 100644
--- a/llvm/lib/Target/X86/X86InstrInfo.cpp
+++ b/llvm/lib/Target/X86/X86InstrInfo.cpp
@@ -2139,34 +2139,6 @@ X86InstrInfo::convertToThreeAddress(MachineFunction::iterator &MFI,
 
   unsigned MIOpc = MI->getOpcode();
   switch (MIOpc) {
-  case X86::SHUFPSrri: {
-    assert(MI->getNumOperands() == 4 && "Unknown shufps instruction!");
-    if (!Subtarget.hasSSE2()) return nullptr;
-
-    unsigned B = MI->getOperand(1).getReg();
-    unsigned C = MI->getOperand(2).getReg();
-    if (B != C) return nullptr;
-    int64_t M = MI->getOperand(3).getImm();
-    NewMI = BuildMI(MF, MI->getDebugLoc(), get(X86::PSHUFDri))
-      .addOperand(Dest).addOperand(Src).addImm(M);
-    break;
-  }
-  case X86::SHUFPDrri: {
-    assert(MI->getNumOperands() == 4 && "Unknown shufpd instruction!");
-    if (!Subtarget.hasSSE2()) return nullptr;
-
-    unsigned B = MI->getOperand(1).getReg();
-    unsigned C = MI->getOperand(2).getReg();
-    if (B != C) return nullptr;
-    unsigned M = MI->getOperand(3).getImm();
-
-    // Convert to PSHUFD mask.
-    M = ((M & 1) << 1) | ((M & 1) << 3) | ((M & 2) << 4) | ((M & 2) << 6)| 0x44;
-
-    NewMI = BuildMI(MF, MI->getDebugLoc(), get(X86::PSHUFDri))
-      .addOperand(Dest).addOperand(Src).addImm(M);
-    break;
-  }
   case X86::SHL64ri: {
     assert(MI->getNumOperands() >= 3 && "Unknown shift instruction!");
     unsigned ShAmt = getTruncatedShiftCount(MI, 2);