[llvm] r274128 - [Docs][CodeGenerator] Don't specify the number of operands in BuildMI

[Krzysztof Parzyszek via llvm-commits]

Author: kparzysz
Date: Wed Jun 29 09:14:59 2016
New Revision: 274128

URL: http://llvm.org/viewvc/llvm-project?rev=274128&view=rev
Log:
[Docs][CodeGenerator] Don't specify the number of operands in BuildMI

Patch by Visoiu Mistrih Francis.

Differential Revision: http://reviews.llvm.org/D21819

Modified:
    llvm/trunk/docs/CodeGenerator.rst
    llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h

Modified: llvm/trunk/docs/CodeGenerator.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/CodeGenerator.rst?rev=274128&r1=274127&r2=274128&view=diff
==============================================================================
--- llvm/trunk/docs/CodeGenerator.rst (original)
+++ llvm/trunk/docs/CodeGenerator.rst Wed Jun 29 09:14:59 2016
@@ -386,32 +386,27 @@ functions make it easy to build arbitrar
 .. code-block:: c++
 
   // Create a 'DestReg = mov 42' (rendered in X86 assembly as 'mov DestReg, 42')
-  // instruction.  The '1' specifies how many operands will be added.
-  MachineInstr *MI = BuildMI(X86::MOV32ri, 1, DestReg).addImm(42);
-
-  // Create the same instr, but insert it at the end of a basic block.
+  // instruction and insert it at the end of the given MachineBasicBlock.
+  const TargetInstrInfo &TII = ...
   MachineBasicBlock &MBB = ...
-  BuildMI(MBB, X86::MOV32ri, 1, DestReg).addImm(42);
+  DebugLoc DL;
+  MachineInstr *MI = BuildMI(MBB, DL, TII.get(X86::MOV32ri), DestReg).addImm(42);
 
   // Create the same instr, but insert it before a specified iterator point.
   MachineBasicBlock::iterator MBBI = ...
-  BuildMI(MBB, MBBI, X86::MOV32ri, 1, DestReg).addImm(42);
+  BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri), DestReg).addImm(42);
 
   // Create a 'cmp Reg, 0' instruction, no destination reg.
-  MI = BuildMI(X86::CMP32ri, 2).addReg(Reg).addImm(0);
+  MI = BuildMI(MBB, DL, TII.get(X86::CMP32ri8)).addReg(Reg).addImm(42);
 
   // Create an 'sahf' instruction which takes no operands and stores nothing.
-  MI = BuildMI(X86::SAHF, 0);
+  MI = BuildMI(MBB, DL, TII.get(X86::SAHF));
 
   // Create a self looping branch instruction.
-  BuildMI(MBB, X86::JNE, 1).addMBB(&MBB);
+  BuildMI(MBB, DL, TII.get(X86::JNE)).addMBB(&MBB);
 
-The key thing to remember with the ``BuildMI`` functions is that you have to
-specify the number of operands that the machine instruction will take.  This
-allows for efficient memory allocation.  You also need to specify if operands
-default to be uses of values, not definitions.  If you need to add a definition
-operand (other than the optional destination register), you must explicitly mark
-it as such:
+If you need to add a definition operand (other than the optional destination
+register), you must explicitly mark it as such:
 
 .. code-block:: c++
 

Modified: llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h?rev=274128&r1=274127&r2=274128&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineInstrBuilder.h Wed Jun 29 09:14:59 2016
@@ -10,7 +10,9 @@
 // This file exposes a function named BuildMI, which is useful for dramatically
 // simplifying how MachineInstr's are created.  It allows use of code like this:
 //
-//   M = BuildMI(X86::ADDrr8, 2).addReg(argVal1).addReg(argVal2);
+//   M = BuildMI(MBB, MI, DL, TII.get(X86::ADD8rr), Dst)
+//           .addReg(argVal1)
+//           .addReg(argVal2);
 //
 //===----------------------------------------------------------------------===//