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Added support for the llvm.readio and llvm.writeio intrinsics. 

On x86, memory operations occur in-order, so these are just lowered into
volatile loads and stores.

llvm-svn: 12936
This commit is contained in:
John Criswell 2004-04-13 22:13:14 +00:00
parent 9042e381d8
commit beded72a08
1 changed files with 29 additions and 0 deletions
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29
llvm/lib/Target/X86/InstSelectSimple.cpp
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@ -1541,6 +1541,35 @@ void ISel::LowerUnknownIntrinsicFunctionCalls(Function &F) {
case Intrinsic::writeport:
// We directly implement these intrinsics
break;
case Intrinsic::readio: {
// On X86, memory operations are in-order. Lower this intrinsic
// into a volatile load.
Instruction *Before = CI->getPrev();
LoadInst * LI = new LoadInst (CI->getOperand(1), "", true, CI);
CI->replaceAllUsesWith (LI);
BB->getInstList().erase (CI);
if (Before) { // Move iterator to instruction after call
I = Before; ++I;
} else {
I = BB->begin();
}
break;
}
case Intrinsic::writeio: {
// On X86, memory operations are in-order. Lower this intrinsic
// into a volatile store.
Instruction *Before = CI->getPrev();
StoreInst * LI = new StoreInst (CI->getOperand(1),
CI->getOperand(2), true, CI);
CI->replaceAllUsesWith (LI);
BB->getInstList().erase (CI);
if (Before) { // Move iterator to instruction after call
I = Before; ++I;
} else {
I = BB->begin();
}
break;
}
default:
// All other intrinsic calls we must lower.
Instruction *Before = CI->getPrev();