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Add support for the PowerPC-specific inline asm Z constraint and y modifier.

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The Z constraint specifies an r+r memory address, and the y modifier expands
to the "r, r" in the asm string. For this initial implementation, the base
register is forced to r0 (which has the special meaning of 0 for r+r addressing
on PowerPC) and the full address is taken in the second register. In the
future, this should be improved.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167388 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel
2012-11-05 18:18:42 +00:00
parent cfe09ed28d
commit 827b7a070d
3 changed files with 41 additions and 2 deletions
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18
lib/Target/PowerPC/PPCAsmPrinter.cpp
View File

@@ -284,8 +284,22 @@ bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant,
const char *ExtraCode,
raw_ostream &O) {
if (ExtraCode && ExtraCode[0])
return true; // Unknown modifier.
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
switch (ExtraCode[0]) {
default: return true; // Unknown modifier.
case 'y': // A memory reference for an X-form instruction
{
const char *RegName = "r0";
if (!Subtarget.isDarwin()) RegName = stripRegisterPrefix(RegName);
O << RegName << ", ";
printOperand(MI, OpNo, O);
return false;
}
}
}
assert(MI->getOperand(OpNo).isReg());
O << "0(";
printOperand(MI, OpNo, O);

11
lib/Target/PowerPC/PPCISelLowering.cpp
View File

@@ -6443,6 +6443,14 @@ PPCTargetLowering::getConstraintType(const std::string &Constraint) const {
case 'v':
case 'y':
return C_RegisterClass;
case 'Z':
// FIXME: While Z does indicate a memory constraint, it specifically
// indicates an r+r address (used in conjunction with the 'y' modifier
// in the replacement string). Currently, we're forcing the base
// register to be r0 in the asm printer (which is interpreted as zero)
// and forming the complete address in the second register. This is
// suboptimal.
return C_Memory;
}
}
return TargetLowering::getConstraintType(Constraint);
@@ -6485,6 +6493,9 @@ PPCTargetLowering::getSingleConstraintMatchWeight(
case 'y':
weight = CW_Register;
break;
case 'Z':
weight = CW_Memory;
break;
}
return weight;
}