- <result> = udiv <ty> <op1>, <op2> ; yields {ty}:result
+ <result> = udiv <ty> <op1>, <op2> ; yields {ty}:result
+ <result> = udiv exact <ty> <op1>, <op2> ; yields {ty}:result
Division by zero leads to undefined behavior.
+If the exact keyword is present, the result value of the + udiv is a trap value if %op1 is not a + multiple of %op2 (as such, "((a udiv exact b) mul b) == a").
+ +
<result> = udiv i32 4, %var ; yields {i32}:result = 4 / %var
diff --git a/include/llvm/Bitcode/LLVMBitCodes.h b/include/llvm/Bitcode/LLVMBitCodes.h
index d15c3ce93ef..7692bd28720 100644
--- a/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/include/llvm/Bitcode/LLVMBitCodes.h
@@ -199,10 +199,10 @@ namespace bitc {
OBO_NO_SIGNED_WRAP = 1
};
- /// SDivOperatorOptionalFlags - Flags for serializing SDivOperator's
- /// SubclassOptionalData contents.
- enum SDivOperatorOptionalFlags {
- SDIV_EXACT = 0
+ /// PossiblyExactOperatorOptionalFlags - Flags for serializing
+ /// PossiblyExactOperator's SubclassOptionalData contents.
+ enum PossiblyExactOperatorOptionalFlags {
+ PEO_EXACT = 0
};
// The function body block (FUNCTION_BLOCK_ID) describes function bodies. It
diff --git a/include/llvm/Constants.h b/include/llvm/Constants.h
index a7653948f13..b782737d31a 100644
--- a/include/llvm/Constants.h
+++ b/include/llvm/Constants.h
@@ -725,6 +725,7 @@ public:
static Constant *getNSWMul(Constant *C1, Constant *C2);
static Constant *getNUWMul(Constant *C1, Constant *C2);
static Constant *getExactSDiv(Constant *C1, Constant *C2);
+ static Constant *getExactUDiv(Constant *C1, Constant *C2);
/// Transparently provide more efficient getOperand methods.
DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
diff --git a/include/llvm/InstrTypes.h b/include/llvm/InstrTypes.h
index 9dcf6883583..1bb50b78fae 100644
--- a/include/llvm/InstrTypes.h
+++ b/include/llvm/InstrTypes.h
@@ -341,7 +341,7 @@ public:
BO->setIsExact(true);
return BO;
}
-
+
/// Helper functions to construct and inspect unary operations (NEG and NOT)
/// via binary operators SUB and XOR:
///
diff --git a/include/llvm/Operator.h b/include/llvm/Operator.h
index 3aae586f144..288edf12244 100644
--- a/include/llvm/Operator.h
+++ b/include/llvm/Operator.h
@@ -173,30 +173,47 @@ public:
}
};
-/// SDivOperator - An Operator with opcode Instruction::SDiv.
-///
-class SDivOperator : public Operator {
+/// PossiblyExactOperator - A udiv or sdiv instruction, which can be marked as
+/// "exact", indicating that no bits are destroyed.
+class PossiblyExactOperator : public Operator {
public:
enum {
IsExact = (1 << 0)
};
-
-private:
- ~SDivOperator(); // do not implement
-
+
friend class BinaryOperator;
friend class ConstantExpr;
void setIsExact(bool B) {
SubclassOptionalData = (SubclassOptionalData & ~IsExact) | (B * IsExact);
}
-
+
+private:
+ ~PossiblyExactOperator(); // do not implement
public:
/// isExact - Test whether this division is known to be exact, with
/// zero remainder.
bool isExact() const {
return SubclassOptionalData & IsExact;
}
-
+
+ static inline bool classof(const ConstantExpr *CE) {
+ return CE->getOpcode() == Instruction::SDiv ||
+ CE->getOpcode() == Instruction::UDiv;
+ }
+ static inline bool classof(const Instruction *I) {
+ return I->getOpcode() == Instruction::SDiv ||
+ I->getOpcode() == Instruction::UDiv;
+ }
+ static inline bool classof(const Value *V) {
+ return (isa(V) && classof(cast(V))) ||
+ (isa(V) && classof(cast(V)));
+ }
+};
+
+/// SDivOperator - An Operator with opcode Instruction::SDiv.
+///
+class SDivOperator : public PossiblyExactOperator {
+public:
// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const SDivOperator *) { return true; }
static inline bool classof(const ConstantExpr *CE) {
@@ -211,6 +228,24 @@ public:
}
};
+/// UDivOperator - An Operator with opcode Instruction::SDiv.
+///
+class UDivOperator : public PossiblyExactOperator {
+public:
+ // Methods for support type inquiry through isa, cast, and dyn_cast:
+ static inline bool classof(const UDivOperator *) { return true; }
+ static inline bool classof(const ConstantExpr *CE) {
+ return CE->getOpcode() == Instruction::UDiv;
+ }
+ static inline bool classof(const Instruction *I) {
+ return I->getOpcode() == Instruction::UDiv;
+ }
+ static inline bool classof(const Value *V) {
+ return (isa(V) && classof(cast(V))) ||
+ (isa(V) && classof(cast(V)));
+ }
+};
+
class GEPOperator : public Operator {
enum {
IsInBounds = (1 << 0)
diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 8ef46344175..6d71c9e3e60 100644
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -2304,7 +2304,7 @@ bool LLParser::ParseValID(ValID &ID, PerFunctionState *PFS) {
if (EatIfPresent(lltok::kw_nuw))
NUW = true;
}
- } else if (Opc == Instruction::SDiv) {
+ } else if (Opc == Instruction::SDiv || Opc == Instruction::UDiv) {
if (EatIfPresent(lltok::kw_exact))
Exact = true;
}
@@ -2347,7 +2347,7 @@ bool LLParser::ParseValID(ValID &ID, PerFunctionState *PFS) {
unsigned Flags = 0;
if (NUW) Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
if (NSW) Flags |= OverflowingBinaryOperator::NoSignedWrap;
- if (Exact) Flags |= SDivOperator::IsExact;
+ if (Exact) Flags |= PossiblyExactOperator::IsExact;
Constant *C = ConstantExpr::get(Opc, Val0, Val1, Flags);
ID.ConstantVal = C;
ID.Kind = ValID::t_Constant;
@@ -3032,7 +3032,8 @@ int LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
case lltok::kw_fsub:
case lltok::kw_fmul: return ParseArithmetic(Inst, PFS, KeywordVal, 2);
- case lltok::kw_sdiv: {
+ case lltok::kw_sdiv:
+ case lltok::kw_udiv: {
bool Exact = false;
if (EatIfPresent(lltok::kw_exact))
Exact = true;
@@ -3043,7 +3044,6 @@ int LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
return Result;
}
- case lltok::kw_udiv:
case lltok::kw_urem:
case lltok::kw_srem: return ParseArithmetic(Inst, PFS, KeywordVal, 1);
case lltok::kw_fdiv:
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index adcad749891..a744d833026 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1090,8 +1090,9 @@ bool BitcodeReader::ParseConstants() {
Flags |= OverflowingBinaryOperator::NoSignedWrap;
if (Record[3] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
- } else if (Opc == Instruction::SDiv) {
- if (Record[3] & (1 << bitc::SDIV_EXACT))
+ } else if (Opc == Instruction::SDiv ||
+ Opc == Instruction::UDiv) {
+ if (Record[3] & (1 << bitc::PEO_EXACT))
Flags |= SDivOperator::IsExact;
}
}
@@ -1905,8 +1906,9 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
cast(I)->setHasNoSignedWrap(true);
if (Record[OpNum] & (1 << bitc::OBO_NO_UNSIGNED_WRAP))
cast(I)->setHasNoUnsignedWrap(true);
- } else if (Opc == Instruction::SDiv) {
- if (Record[OpNum] & (1 << bitc::SDIV_EXACT))
+ } else if (Opc == Instruction::SDiv ||
+ Opc == Instruction::UDiv) {
+ if (Record[OpNum] & (1 << bitc::PEO_EXACT))
cast(I)->setIsExact(true);
}
}
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 702a611cbe5..f8ef8c668c4 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -470,9 +470,10 @@ static uint64_t GetOptimizationFlags(const Value *V) {
Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
if (OBO->hasNoUnsignedWrap())
Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
- } else if (const SDivOperator *Div = dyn_cast(V)) {
- if (Div->isExact())
- Flags |= 1 << bitc::SDIV_EXACT;
+ } else if (const PossiblyExactOperator *PEO =
+ dyn_cast(V)) {
+ if (PEO->isExact())
+ Flags |= 1 << bitc::PEO_EXACT;
}
return Flags;
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 035ee721bfd..559788b4a90 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -135,8 +135,8 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
BO->getOpcode() == Instruction::SDiv)) {
Value *Op0BO = BO->getOperand(0), *Op1BO = BO->getOperand(1);
- // If the division is exact, X % Y is zero.
- if (SDivOperator *SDiv = dyn_cast(BO))
+ // If the division is exact, X % Y is zero, so we end up with X or -X.
+ if (PossiblyExactOperator *SDiv = dyn_cast(BO))
if (SDiv->isExact()) {
if (Op1BO == Op1C)
return ReplaceInstUsesWith(I, Op0BO);
diff --git a/lib/VMCore/AsmWriter.cpp b/lib/VMCore/AsmWriter.cpp
index 1a11d9c7980..5b56cb572cf 100644
--- a/lib/VMCore/AsmWriter.cpp
+++ b/lib/VMCore/AsmWriter.cpp
@@ -831,7 +831,8 @@ static void WriteOptimizationInfo(raw_ostream &Out, const User *U) {
Out << " nuw";
if (OBO->hasNoSignedWrap())
Out << " nsw";
- } else if (const SDivOperator *Div = dyn_cast(U)) {
+ } else if (const PossiblyExactOperator *Div =
+ dyn_cast(U)) {
if (Div->isExact())
Out << " exact";
} else if (const GEPOperator *GEP = dyn_cast(U)) {
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 62117b22e6c..d2359e5bcda 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -683,7 +683,12 @@ Constant* ConstantExpr::getNUWMul(Constant* C1, Constant* C2) {
Constant* ConstantExpr::getExactSDiv(Constant* C1, Constant* C2) {
return getTy(C1->getType(), Instruction::SDiv, C1, C2,
- SDivOperator::IsExact);
+ PossiblyExactOperator::IsExact);
+}
+
+Constant* ConstantExpr::getExactUDiv(Constant* C1, Constant* C2) {
+ return getTy(C1->getType(), Instruction::UDiv, C1, C2,
+ PossiblyExactOperator::IsExact);
}
// Utility function for determining if a ConstantExpr is a CastOp or not. This
diff --git a/lib/VMCore/Instructions.cpp b/lib/VMCore/Instructions.cpp
index 6b561f34af2..d1290281cb1 100644
--- a/lib/VMCore/Instructions.cpp
+++ b/lib/VMCore/Instructions.cpp
@@ -1822,7 +1822,7 @@ void BinaryOperator::setHasNoSignedWrap(bool b) {
}
void BinaryOperator::setIsExact(bool b) {
- cast(this)->setIsExact(b);
+ cast(this)->setIsExact(b);
}
bool BinaryOperator::hasNoUnsignedWrap() const {
@@ -1834,7 +1834,7 @@ bool BinaryOperator::hasNoSignedWrap() const {
}
bool BinaryOperator::isExact() const {
- return cast(this)->isExact();
+ return cast(this)->isExact();
}
//===----------------------------------------------------------------------===//
diff --git a/test/Assembler/flags.ll b/test/Assembler/flags.ll
index 32419090597..82b35b5c210 100644
--- a/test/Assembler/flags.ll
+++ b/test/Assembler/flags.ll
@@ -104,6 +104,19 @@ define i64 @sdiv_plain(i64 %x, i64 %y) {
ret i64 %z
}
+define i64 @udiv_exact(i64 %x, i64 %y) {
+; CHECK: %z = udiv exact i64 %x, %y
+ %z = udiv exact i64 %x, %y
+ ret i64 %z
+}
+
+define i64 @udiv_plain(i64 %x, i64 %y) {
+; CHECK: %z = udiv i64 %x, %y
+ %z = udiv i64 %x, %y
+ ret i64 %z
+}
+
+
define i64* @gep_nw(i64* %p, i64 %x) {
; CHECK: %z = getelementptr inbounds i64* %p, i64 %x
%z = getelementptr inbounds i64* %p, i64 %x
@@ -136,6 +149,11 @@ define i64 @sdiv_exact_ce() {
ret i64 sdiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
}
+define i64 @udiv_exact_ce() {
+; CHECK: ret i64 udiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
+ ret i64 udiv exact (i64 ptrtoint (i64* @addr to i64), i64 91)
+}
+
define i64* @gep_nw_ce() {
; CHECK: ret i64* getelementptr inbounds (i64* @addr, i64 171)
ret i64* getelementptr inbounds (i64* @addr, i64 171)
@@ -210,3 +228,4 @@ define i64 @mul_unsigned_ce() {
; CHECK: ret i64 mul nuw (i64 ptrtoint (i64* @addr to i64), i64 91)
ret i64 mul nuw (i64 ptrtoint (i64* @addr to i64), i64 91)
}
+
diff --git a/test/Transforms/InstCombine/exact-sdiv.ll b/test/Transforms/InstCombine/exact.ll
similarity index 87%
rename from test/Transforms/InstCombine/exact-sdiv.ll
rename to test/Transforms/InstCombine/exact.ll
index e5677541e95..940469ea711 100644
--- a/test/Transforms/InstCombine/exact-sdiv.ll
+++ b/test/Transforms/InstCombine/exact.ll
@@ -50,3 +50,11 @@ define i32 @b1(i32 %x) {
%z = mul i32 %y, -3
ret i32 %z
}
+
+; CHECK: i32 @b2
+; CHECK: ret i32 %x
+define i32 @b2(i32 %x, i32 %w) {
+ %y = udiv exact i32 %x, %w
+ %z = mul i32 %y, %w
+ ret i32 %z
+}