Fix the problems with callee popped argument lists
llvm-svn: 21988
diff --git a/llvm/lib/Target/X86/X86ISelPattern.cpp b/llvm/lib/Target/X86/X86ISelPattern.cpp
index ba36443..72403be 100644
--- a/llvm/lib/Target/X86/X86ISelPattern.cpp
+++ b/llvm/lib/Target/X86/X86ISelPattern.cpp
@@ -3746,7 +3746,43 @@
// Amount the callee added to the stack pointer.
Tmp2 = cast<ConstantSDNode>(N.getOperand(2))->getValue();
- BuildMI(BB, X86::ADJCALLSTACKUP, 2).addImm(Tmp1).addImm(Tmp2);
+
+ // This hackery is due to the fact that we don't want to emit this code:
+ // call foo
+ // mov vreg, EAX
+ // adjcallstackup
+ //
+ // Because if foo is a fastcc call and if vreg gets spilled, we might end up
+ // with this:
+ // call foo
+ // mov [ESP+offset], EAX ;; Offset doesn't consider the 12!
+ // sub ESP, 12
+ //
+ // To avoid this, we force the adjcallstackup instruction before the 0, 1 or
+ // 2 moves that occur after the call. The correct way to fix this is to use
+ // target-specific DAG nodes in the call sequence. FIXME!
+ //
+ if (EnableFastCC) {
+ // This code should be safe. Be defensive for LLVM 1.5 release though.
+ assert(!BB->empty());
+ MachineBasicBlock::iterator PrevI = --BB->end();
+ if (PrevI->getOpcode() == X86::CALLpcrel32 ||
+ PrevI->getOpcode() == X86::CALL32r)
+ ++PrevI;
+ else if (PrevI != BB->begin() &&
+ ((--PrevI)->getOpcode() == X86::CALLpcrel32 ||
+ PrevI->getOpcode() == X86::CALL32r))
+ ++PrevI;
+ else if (PrevI != BB->begin() &&
+ ((--PrevI)->getOpcode() == X86::CALLpcrel32 ||
+ PrevI->getOpcode() == X86::CALL32r))
+ ++PrevI;
+ else
+ PrevI = BB->end();
+ BuildMI(*BB, PrevI, X86::ADJCALLSTACKUP, 2).addImm(Tmp1).addImm(Tmp2);
+ } else {
+ BuildMI(*BB, PrevI, X86::ADJCALLSTACKUP, 2).addImm(Tmp1).addImm(Tmp2);
+ }
return;
case ISD::MEMSET: {
Select(N.getOperand(0)); // Select the chain.