diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp index 41734f6ac9d..57fe870158b 100644 --- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp +++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp @@ -1450,7 +1450,16 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) { return Builder->CreateICmp(LHSCC, NewOr, LHSCst); } } - + + // (icmp ult (X + CA), C1) | (icmp eq X, C2) -> (icmp ult (X + CA), C1 + 1) + // iff C2 + CA == C1. + if (LHSCC == ICmpInst::ICMP_ULT) { + ConstantInt *AddCst; + if (match(Val, m_Add(m_Specific(Val2), m_ConstantInt(AddCst)))) + if (RHSCst->getValue() + AddCst->getValue() == LHSCst->getValue()) + return Builder->CreateICmp(LHSCC, Val, AddOne(LHSCst)); + } + // From here on, we only handle: // (icmp1 A, C1) | (icmp2 A, C2) --> something simpler. if (Val != Val2) return 0; diff --git a/test/Transforms/InstCombine/or.ll b/test/Transforms/InstCombine/or.ll index 500cad2ad64..f82f9faab2d 100644 --- a/test/Transforms/InstCombine/or.ll +++ b/test/Transforms/InstCombine/or.ll @@ -376,3 +376,17 @@ define i32 @test35(i32 %a, i32 %b) { ; CHECK-NEXT: or i32 %a, %b ; CHECK-NEXT: or i32 %1, 1135 } + +define i1 @test36(i32 %x) { + %cmp1 = icmp eq i32 %x, 23 + %cmp2 = icmp eq i32 %x, 24 + %ret1 = or i1 %cmp1, %cmp2 + %cmp3 = icmp eq i32 %x, 25 + %ret2 = or i1 %ret1, %cmp3 + ret i1 %ret2 +; CHECK: @test36 +; CHECK-NEXT: %x.off = add i32 %x, -23 +; CHECK-NEXT: icmp ult i32 %x.off, 3 +; CHECK-NEXT: ret i1 +} +