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For amusement, implement SADDO, SSUBO, UADDO, USUBO

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for promoted integer types, eg: i16 on ppc-32, or
i24 on any platform.  Complete support for arbitrary
precision integers would require handling expanded
integer types, eg: i128, but I couldn't be bothered.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60834 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2008-12-10 12:30:42 +00:00
parent 0cfe05270c
commit ab0c578bfd
3 changed files with 123 additions and 20 deletions
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96
lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
View File

@ -92,11 +92,11 @@ void DAGTypeLegalizer::PromoteIntegerResult(SDNode *N, unsigned ResNo) {
case ISD::UREM: Result = PromoteIntRes_UDIV(N); break;
case ISD::SADDO:
case ISD::SSUBO: Result = PromoteIntRes_SADDSUBO(N, ResNo); break;
case ISD::UADDO:
case ISD::SSUBO:
case ISD::USUBO:
case ISD::USUBO: Result = PromoteIntRes_UADDSUBO(N, ResNo); break;
case ISD::SMULO:
case ISD::UMULO: Result = PromoteIntRes_XALUO(N, ResNo); break;
case ISD::UMULO: Result = PromoteIntRes_XMULO(N, ResNo); break;
case ISD::ATOMIC_LOAD_ADD_8:
case ISD::ATOMIC_LOAD_SUB_8:
@ -428,6 +428,49 @@ SDValue DAGTypeLegalizer::PromoteIntRes_LOAD(LoadSDNode *N) {
return Res;
}
/// Promote the overflow flag of an overflowing arithmetic node.
SDValue DAGTypeLegalizer::PromoteIntRes_Overflow(SDNode *N) {
// Simply change the return type of the boolean result.
MVT NVT = TLI.getTypeToTransformTo(N->getValueType(1));
MVT ValueVTs[] = { N->getValueType(0), NVT };
SDValue Ops[] = { N->getOperand(0), N->getOperand(1) };
SDValue Res = DAG.getNode(N->getOpcode(), DAG.getVTList(ValueVTs, 2), Ops, 2);
// Modified the sum result - switch anything that used the old sum to use
// the new one.
ReplaceValueWith(SDValue(N, 0), Res);
return SDValue(Res.getNode(), 1);
}
SDValue DAGTypeLegalizer::PromoteIntRes_SADDSUBO(SDNode *N, unsigned ResNo) {
if (ResNo == 1)
return PromoteIntRes_Overflow(N);
// The operation overflowed iff the result in the larger type is not the
// sign extension of its truncation to the original type.
SDValue LHS = SExtPromotedInteger(N->getOperand(0));
SDValue RHS = SExtPromotedInteger(N->getOperand(1));
MVT OVT = N->getOperand(0).getValueType();
MVT NVT = LHS.getValueType();
// Do the arithmetic in the larger type.
unsigned Opcode = N->getOpcode() == ISD::SADDO ? ISD::ADD : ISD::SUB;
SDValue Res = DAG.getNode(Opcode, NVT, LHS, RHS);
// Calculate the overflow flag: sign extend the arithmetic result from
// the original type.
SDValue Ofl = DAG.getNode(ISD::SIGN_EXTEND_INREG, NVT, Res,
DAG.getValueType(OVT));
// Overflowed if and only if this is not equal to Res.
Ofl = DAG.getSetCC(N->getValueType(1), Ofl, Res, ISD::SETNE);
// Use the calculated overflow everywhere.
ReplaceValueWith(SDValue(N, 1), Ofl);
return Res;
}
SDValue DAGTypeLegalizer::PromoteIntRes_SDIV(SDNode *N) {
// Sign extend the input.
SDValue LHS = SExtPromotedInteger(N->getOperand(0));
@ -515,6 +558,33 @@ SDValue DAGTypeLegalizer::PromoteIntRes_TRUNCATE(SDNode *N) {
return DAG.getNode(ISD::TRUNCATE, NVT, Res);
}
SDValue DAGTypeLegalizer::PromoteIntRes_UADDSUBO(SDNode *N, unsigned ResNo) {
if (ResNo == 1)
return PromoteIntRes_Overflow(N);
// The operation overflowed iff the result in the larger type is not the
// zero extension of its truncation to the original type.
SDValue LHS = ZExtPromotedInteger(N->getOperand(0));
SDValue RHS = ZExtPromotedInteger(N->getOperand(1));
MVT OVT = N->getOperand(0).getValueType();
MVT NVT = LHS.getValueType();
// Do the arithmetic in the larger type.
unsigned Opcode = N->getOpcode() == ISD::UADDO ? ISD::ADD : ISD::SUB;
SDValue Res = DAG.getNode(Opcode, NVT, LHS, RHS);
// Calculate the overflow flag: zero extend the arithmetic result from
// the original type.
SDValue Ofl = DAG.getZeroExtendInReg(Res, OVT);
// Overflowed if and only if this is not equal to Res.
Ofl = DAG.getSetCC(N->getValueType(1), Ofl, Res, ISD::SETNE);
// Use the calculated overflow everywhere.
ReplaceValueWith(SDValue(N, 1), Ofl);
return Res;
}
SDValue DAGTypeLegalizer::PromoteIntRes_UDIV(SDNode *N) {
// Zero extend the input.
SDValue LHS = ZExtPromotedInteger(N->getOperand(0));
@ -522,22 +592,6 @@ SDValue DAGTypeLegalizer::PromoteIntRes_UDIV(SDNode *N) {
return DAG.getNode(N->getOpcode(), LHS.getValueType(), LHS, RHS);
}
SDValue DAGTypeLegalizer::PromoteIntRes_XALUO(SDNode *N, unsigned ResNo) {
assert(ResNo == 1 && "Only boolean result promotion currently supported!");
// Simply change the return type of the boolean result.
MVT NVT = TLI.getTypeToTransformTo(N->getValueType(1));
MVT ValueVTs[] = { N->getValueType(0), NVT };
SDValue Ops[] = { N->getOperand(0), N->getOperand(1) };
SDValue Res = DAG.getNode(N->getOpcode(), DAG.getVTList(ValueVTs, 2), Ops, 2);
// Modified the sum result - switch anything that used the old sum to use
// the new one.
ReplaceValueWith(SDValue(N, 0), Res);
return SDValue(Res.getNode(), 1);
}
SDValue DAGTypeLegalizer::PromoteIntRes_UNDEF(SDNode *N) {
return DAG.getNode(ISD::UNDEF, TLI.getTypeToTransformTo(N->getValueType(0)));
}
@ -580,6 +634,10 @@ SDValue DAGTypeLegalizer::PromoteIntRes_VAARG(SDNode *N) {
return Res;
}
SDValue DAGTypeLegalizer::PromoteIntRes_XMULO(SDNode *N, unsigned ResNo) {
assert(ResNo == 1 && "Only boolean result promotion currently supported!");
return PromoteIntRes_Overflow(N);
}
//===----------------------------------------------------------------------===//
// Integer Operand Promotion

5
lib/CodeGen/SelectionDAG/LegalizeTypes.h
View File

@ -257,6 +257,8 @@ private:
SDValue PromoteIntRes_FP_TO_XINT(SDNode *N);
SDValue PromoteIntRes_INT_EXTEND(SDNode *N);
SDValue PromoteIntRes_LOAD(LoadSDNode *N);
SDValue PromoteIntRes_Overflow(SDNode *N);
SDValue PromoteIntRes_SADDSUBO(SDNode *N, unsigned ResNo);
SDValue PromoteIntRes_SDIV(SDNode *N);
SDValue PromoteIntRes_SELECT(SDNode *N);
SDValue PromoteIntRes_SELECT_CC(SDNode *N);
@ -267,10 +269,11 @@ private:
SDValue PromoteIntRes_SRA(SDNode *N);
SDValue PromoteIntRes_SRL(SDNode *N);
SDValue PromoteIntRes_TRUNCATE(SDNode *N);
SDValue PromoteIntRes_UADDSUBO(SDNode *N, unsigned ResNo);
SDValue PromoteIntRes_UDIV(SDNode *N);
SDValue PromoteIntRes_UNDEF(SDNode *N);
SDValue PromoteIntRes_VAARG(SDNode *N);
SDValue PromoteIntRes_XALUO(SDNode *N, unsigned ResNo);
SDValue PromoteIntRes_XMULO(SDNode *N, unsigned ResNo);
// Integer Operand Promotion.
bool PromoteIntegerOperand(SDNode *N, unsigned OperandNo);

42
test/CodeGen/Generic/add-with-overflow-24.ll Normal file
View File

@ -0,0 +1,42 @@
; RUN: llvm-as < %s | llc
@ok = internal constant [4 x i8] c"%d\0A\00"
@no = internal constant [4 x i8] c"no\0A\00"
define i1 @func1(i24 signext %v1, i24 signext %v2) nounwind {
entry:
%t = call {i24, i1} @llvm.sadd.with.overflow.i24(i24 %v1, i24 %v2)
%sum = extractvalue {i24, i1} %t, 0
%sum32 = sext i24 %sum to i32
%obit = extractvalue {i24, i1} %t, 1
br i1 %obit, label %overflow, label %normal
normal:
%t1 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @ok, i32 0, i32 0), i32 %sum32 ) nounwind
ret i1 true
overflow:
%t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
ret i1 false
}
define i1 @func2(i24 zeroext %v1, i24 zeroext %v2) nounwind {
entry:
%t = call {i24, i1} @llvm.uadd.with.overflow.i24(i24 %v1, i24 %v2)
%sum = extractvalue {i24, i1} %t, 0
%sum32 = zext i24 %sum to i32
%obit = extractvalue {i24, i1} %t, 1
br i1 %obit, label %carry, label %normal
normal:
%t1 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @ok, i32 0, i32 0), i32 %sum32 ) nounwind
ret i1 true
carry:
%t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
ret i1 false
}
declare i32 @printf(i8*, ...) nounwind
declare {i24, i1} @llvm.sadd.with.overflow.i24(i24, i24)
declare {i24, i1} @llvm.uadd.with.overflow.i24(i24, i24)