[llvm-commits] CVS: llvm/lib/Target/X86/InstSelectSimple.cpp

[Chris Lattner]

Changes in directory llvm/lib/Target/X86:

InstSelectSimple.cpp updated: 1.91 -> 1.92

---
Log message:

Emit pseudo instructions to indicate that some registers are live on entrance
and exit of the function.  This fixes bug: Jello/2003-05-06-LivenessClobber.llx
and the Fhourstones benchmark



---
Diffs of the changes:

Index: llvm/lib/Target/X86/InstSelectSimple.cpp
diff -u llvm/lib/Target/X86/InstSelectSimple.cpp:1.91 llvm/lib/Target/X86/InstSelectSimple.cpp:1.92
--- llvm/lib/Target/X86/InstSelectSimple.cpp:1.91	Fri May  2 21:18:17 2003
+++ llvm/lib/Target/X86/InstSelectSimple.cpp	Tue May  6 16:32:22 2003
@@ -78,6 +78,11 @@
         F->getBasicBlockList().push_back(MBBMap[I] = new MachineBasicBlock(I));
 
       BB = &F->front();
+
+      // Declare that the stack pointer is live on entrance to the function
+      BuildMI(BB, X86::IMPLICIT_DEF, 0, X86::ESP);
+
+      // Copy incoming arguments off of the stack...
       LoadArgumentsToVirtualRegs(Fn);
 
       // Instruction select everything except PHI nodes
@@ -671,13 +676,19 @@
   case cShort:
   case cInt:
     promote32(X86::EAX, ValueRecord(RetReg, RetVal->getType()));
+    // Declare that EAX is live on exit
+    BuildMI(BB, X86::IMPLICIT_USE, 1).addReg(X86::EAX);
     break;
   case cFP:                   // Floats & Doubles: Return in ST(0)
     BuildMI(BB, X86::FpSETRESULT, 1).addReg(RetReg);
+    // Declare that top-of-stack is live on exit
+    BuildMI(BB, X86::IMPLICIT_USE, 1).addReg(X86::ST0);
     break;
   case cLong:
     BuildMI(BB, X86::MOVrr32, 1, X86::EAX).addReg(RetReg);
     BuildMI(BB, X86::MOVrr32, 1, X86::EDX).addReg(RetReg+1);
+    // Declare that EAX & EDX are live on exit
+    BuildMI(BB, X86::IMPLICIT_USE, 2).addReg(X86::EAX).addReg(X86::EDX);
     break;
   default:
     visitInstruction(I);