Add support for the rep movs[bwd] instructions, and emit them when code
generating the llvm.memcpy intrinsic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11351 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp
index 9df7697..67849e2 100644
--- a/lib/Target/X86/X86ISelSimple.cpp
+++ b/lib/Target/X86/X86ISelSimple.cpp
@@ -1157,6 +1157,7 @@
case Intrinsic::va_start:
case Intrinsic::va_copy:
case Intrinsic::va_end:
+ case Intrinsic::memcpy:
// We directly implement these intrinsics
break;
default:
@@ -1188,6 +1189,58 @@
return;
case Intrinsic::va_end: return; // Noop on X86
+ case Intrinsic::memcpy: {
+ assert(CI.getNumOperands() == 5 && "Illegal llvm.memcpy call!");
+ unsigned Align = 1;
+ if (ConstantInt *AlignC = dyn_cast<ConstantInt>(CI.getOperand(4))) {
+ Align = AlignC->getRawValue();
+ if (Align == 0) Align = 1;
+ }
+
+ // Turn the byte code into # iterations
+ unsigned ByteReg = getReg(CI.getOperand(3));
+ unsigned CountReg;
+
+ switch (Align & 3) {
+ case 2: // WORD aligned
+ CountReg = makeAnotherReg(Type::IntTy);
+ BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(1);
+ break;
+ case 0: // DWORD aligned
+ CountReg = makeAnotherReg(Type::IntTy);
+ BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(2);
+ break;
+ case 1: // BYTE aligned
+ case 3: // BYTE aligned
+ CountReg = ByteReg;
+ break;
+ }
+
+ // No matter what the alignment is, we put the source in ESI, the
+ // destination in EDI, and the count in ECX.
+ TmpReg1 = getReg(CI.getOperand(1));
+ TmpReg2 = getReg(CI.getOperand(2));
+ BuildMI(BB, X86::MOVrr32, 1, X86::ECX).addReg(CountReg);
+ BuildMI(BB, X86::MOVrr32, 1, X86::EDI).addReg(TmpReg1);
+ BuildMI(BB, X86::MOVrr32, 1, X86::ESI).addReg(TmpReg2);
+
+ unsigned Bytes = getReg(CI.getOperand(3));
+ switch (Align & 3) {
+ case 1: // BYTE aligned
+ case 3: // BYTE aligned
+ BuildMI(BB, X86::REP_MOVSB, 0);
+ break;
+ case 2: // WORD aligned
+ BuildMI(BB, X86::REP_MOVSW, 0);
+ break;
+ case 0: // DWORD aligned
+ BuildMI(BB, X86::REP_MOVSD, 0);
+ break;
+ }
+
+ return;
+ }
+
default: assert(0 && "Error: unknown intrinsics should have been lowered!");
}
}