// Put the new code above the original add, in case there are any uses of the
// add between the add and the compare.
- Builder->SetInsertPoint(OrigAdd->getParent(), BasicBlock::iterator(OrigAdd));
+ Builder->SetInsertPoint(OrigAdd);
Value *TruncA = Builder->CreateTrunc(A, NewType, A->getName()+".trunc");
Value *TruncB = Builder->CreateTrunc(B, NewType, B->getName()+".trunc");
return ExtractValueInst::Create(Call, 1, "sadd.overflow");
}
+static Instruction *ProcessUAddIdiom(Instruction &I, Value *OrigAddV,
+ InstCombiner &IC) {
+ // Don't bother doing this transformation for pointers, don't do it for
+ // vectors.
+ if (!isa<IntegerType>(OrigAddV->getType())) return 0;
+
+ // If the add is a constant expr, then we don't bother transforming it.
+ Instruction *OrigAdd = dyn_cast<Instruction>(OrigAddV);
+ if (OrigAdd == 0) return 0;
+
+ Value *LHS = OrigAdd->getOperand(0), *RHS = OrigAdd->getOperand(1);
+
+ // Put the new code above the original add, in case there are any uses of the
+ // add between the add and the compare.
+ InstCombiner::BuilderTy *Builder = IC.Builder;
+ Builder->SetInsertPoint(OrigAdd);
+
+ Module *M = I.getParent()->getParent()->getParent();
+ const Type *Ty = LHS->getType();
+ Value *F = Intrinsic::getDeclaration(M, Intrinsic::uadd_with_overflow, &Ty,1);
+ CallInst *Call = Builder->CreateCall2(F, LHS, RHS, "uadd");
+ Value *Add = Builder->CreateExtractValue(Call, 0);
+
+ IC.ReplaceInstUsesWith(*OrigAdd, Add);
+
+ // The original icmp gets replaced with the overflow value.
+ return ExtractValueInst::Create(Call, 1, "uadd.overflow");
+}
+
Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
bool Changed = false;
}
unsigned BitWidth = 0;
- if (TD)
- BitWidth = TD->getTypeSizeInBits(Ty->getScalarType());
- else if (Ty->isIntOrIntVectorTy())
+ if (Ty->isIntOrIntVectorTy())
BitWidth = Ty->getScalarSizeInBits();
-
+ else if (TD) // Pointers require TD info to get their size.
+ BitWidth = TD->getTypeSizeInBits(Ty->getScalarType());
+
bool isSignBit = false;
// See if we are doing a comparison with a constant.
if (match(Op0, m_Not(m_Value(A))) &&
match(Op1, m_Not(m_Value(B))))
return new ICmpInst(I.getPredicate(), B, A);
+
+ // (a+b) <u a --> llvm.uadd.with.overflow.
+ // (a+b) <u b --> llvm.uadd.with.overflow.
+ if (I.getPredicate() == ICmpInst::ICMP_ULT &&
+ match(Op0, m_Add(m_Value(A), m_Value(B))) &&
+ (Op1 == A || Op1 == B))
+ if (Instruction *R = ProcessUAddIdiom(I, Op0, *this))
+ return R;
+
+ // a >u (a+b) --> llvm.uadd.with.overflow.
+ // b >u (a+b) --> llvm.uadd.with.overflow.
+ if (I.getPredicate() == ICmpInst::ICMP_UGT &&
+ match(Op1, m_Add(m_Value(A), m_Value(B))) &&
+ (Op0 == A || Op0 == B))
+ if (Instruction *R = ProcessUAddIdiom(I, Op1, *this))
+ return R;
}
if (I.isEquality()) {
; CHECK: ret i8
}
+; CHECK: @test5
+; CHECK: llvm.uadd.with.overflow
+; CHECK: ret i64
+define i64 @test5(i64 %a, i64 %b) nounwind ssp {
+entry:
+ %add = add i64 %b, %a
+ %cmp = icmp ult i64 %add, %a
+ %Q = select i1 %cmp, i64 %b, i64 42
+ ret i64 %Q
+}
+
+; CHECK: @test6
+; CHECK: llvm.uadd.with.overflow
+; CHECK: ret i64
+define i64 @test6(i64 %a, i64 %b) nounwind ssp {
+entry:
+ %add = add i64 %b, %a
+ %cmp = icmp ult i64 %add, %b
+ %Q = select i1 %cmp, i64 %b, i64 42
+ ret i64 %Q
+}
+
+; CHECK: @test7
+; CHECK: llvm.uadd.with.overflow
+; CHECK: ret i64
+define i64 @test7(i64 %a, i64 %b) nounwind ssp {
+entry:
+ %add = add i64 %b, %a
+ %cmp = icmp ugt i64 %b, %add
+ %Q = select i1 %cmp, i64 %b, i64 42
+ ret i64 %Q
+}
+
+