/// Return true if the value is negative zero or null value.
bool isZeroValue() const;
+ /// \brief Return true if the value is the smallest signed value.
+ bool isMinSignedValue() const;
+
/// canTrap - Return true if evaluation of this constant could trap. This is
/// true for things like constant expressions that could divide by zero.
bool canTrap() const;
return false;
}
+bool Constant::isMinSignedValue() const {
+ // Check for INT_MIN integers
+ if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
+ return CI->isMinValue(/*isSigned=*/true);
+
+ // Check for FP which are bitcasted from INT_MIN integers
+ if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
+ return CFP->getValueAPF().bitcastToAPInt().isMinSignedValue();
+
+ // Check for constant vectors which are splats of INT_MIN values.
+ if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
+ if (Constant *Splat = CV->getSplatValue())
+ return Splat->isMinSignedValue();
+
+ // Check for constant vectors which are splats of INT_MIN values.
+ if (const ConstantDataVector *CV = dyn_cast<ConstantDataVector>(this))
+ if (Constant *Splat = CV->getSplatValue())
+ return Splat->isMinSignedValue();
+
+ return false;
+}
+
// Constructor to create a '0' constant of arbitrary type...
Constant *Constant::getNullValue(Type *Ty) {
switch (Ty->getTypeID()) {
return BinaryOperator::CreateAnd(Op0,
Builder->CreateNot(Y, Y->getName() + ".not"));
- // 0 - (X sdiv C) -> (X sdiv -C)
- if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) &&
- match(Op0, m_Zero()))
+ // 0 - (X sdiv C) -> (X sdiv -C) provided the negation doesn't overflow.
+ if (match(Op1, m_SDiv(m_Value(X), m_Constant(C))) && match(Op0, m_Zero()) &&
+ !C->isMinSignedValue())
return BinaryOperator::CreateSDiv(X, ConstantExpr::getNeg(C));
// 0 - (X << Y) -> (-X << Y) when X is freely negatable.
; CHECK-NEXT: %sub = mul <2 x i64> %A, <i64 7, i64 15>
; CHECK-NEXT: ret <2 x i64> %sub
}
+
+define <2 x i64> @test37(<2 x i64> %A) {
+ %shl = shl <2 x i64> %A, <i64 3, i64 4>
+ %sub = sub <2 x i64> %shl, %A
+ ret <2 x i64> %sub
+; CHECK-LABEL: @test37(
+; CHECK-NEXT: %sub = mul <2 x i64> %A, <i64 7, i64 15>
+; CHECK-NEXT: ret <2 x i64> %sub
+}
+
+define i32 @test38(i32 %A) {
+ %div = sdiv i32 %A, -2147483648
+ %sub = sub nsw i32 0, %div
+ ret i32 %sub
+; CHECK-LABEL: @test38(
+; CHECK-NEXT: [[DIV:%.*]] = sdiv i32 %A, -2147483648
+; CHECK-NEXT: [[SUB:%.*]] = sub nsw i32 0, [[DIV]]
+; CHECK-NEXT: ret i32 [[SUB]]
+}