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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6010 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index a65a427..3a12d5e 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -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);