[llvm-commits] [llvm] r108073 - /llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Sun Jul 11 00:16:54 2010
New Revision: 108073

URL: http://llvm.org/viewvc/llvm-project?rev=108073&view=rev
Log:
Use COPY for fast-isel bitconvert, but don't create cross-class copies.

This doesn't change the behavior of SelectBitcast for X86.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp?rev=108073&r1=108072&r2=108073&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/FastISel.cpp Sun Jul 11 00:16:54 2010
@@ -671,13 +671,12 @@
   if (SrcVT.getSimpleVT() == DstVT.getSimpleVT()) {
     TargetRegisterClass* SrcClass = TLI.getRegClassFor(SrcVT);
     TargetRegisterClass* DstClass = TLI.getRegClassFor(DstVT);
-    ResultReg = createResultReg(DstClass);
-    
-    bool InsertedCopy = TII.copyRegToReg(*FuncInfo.MBB, FuncInfo.InsertPt,
-                                         ResultReg, Op0,
-                                         DstClass, SrcClass, DL);
-    if (!InsertedCopy)
-      ResultReg = 0;
+    // Don't attempt a cross-class copy. It will likely fail.
+    if (SrcClass == DstClass) {
+      ResultReg = createResultReg(DstClass);
+      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(TargetOpcode::COPY),
+              ResultReg).addReg(Op0);
+    }
   }
   
   // If the reg-reg copy failed, select a BIT_CONVERT opcode.