diff options
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 48 | ||||
| -rw-r--r-- | test/Transforms/InstSimplify/maxmin.ll | 88 |
2 files changed, 134 insertions, 2 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 3028f17..e7ef6ff 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/lib/Analysis/InstructionSimplify.cpp @@ -1873,7 +1873,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE; CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B". - // Signed max/min. + // Signed variants on "max(a,b)>=a -> true". if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { if (A != RHS) std::swap(A, B); // smax(A, B) pred A. EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B". @@ -1929,7 +1929,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, } } - // Unsigned max/min. + // Unsigned variants on "max(a,b)>=a -> true". P = CmpInst::BAD_ICMP_PREDICATE; if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) { if (A != RHS) std::swap(A, B); // umax(A, B) pred A. @@ -1986,6 +1986,50 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, } } + // Variants on "max(x,y) >= min(x,z)". + Value *C, *D; + if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && + match(RHS, m_SMin(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // max(x, ?) pred min(x, ?). + if (Pred == CmpInst::ICMP_SGE) + // Always true. + return Constant::getAllOnesValue(ITy); + if (Pred == CmpInst::ICMP_SLT) + // Always false. + return Constant::getNullValue(ITy); + } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) && + match(RHS, m_SMax(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // min(x, ?) pred max(x, ?). + if (Pred == CmpInst::ICMP_SLE) + // Always true. + return Constant::getAllOnesValue(ITy); + if (Pred == CmpInst::ICMP_SGT) + // Always false. + return Constant::getNullValue(ITy); + } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && + match(RHS, m_UMin(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // max(x, ?) pred min(x, ?). + if (Pred == CmpInst::ICMP_UGE) + // Always true. + return Constant::getAllOnesValue(ITy); + if (Pred == CmpInst::ICMP_ULT) + // Always false. + return Constant::getNullValue(ITy); + } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) && + match(RHS, m_UMax(m_Value(C), m_Value(D))) && + (A == C || A == D || B == C || B == D)) { + // min(x, ?) pred max(x, ?). + if (Pred == CmpInst::ICMP_ULE) + // Always true. + return Constant::getAllOnesValue(ITy); + if (Pred == CmpInst::ICMP_UGT) + // Always false. + return Constant::getNullValue(ITy); + } + // If the comparison is with the result of a select instruction, check whether // comparing with either branch of the select always yields the same value. if (isa<SelectInst>(LHS) || isa<SelectInst>(RHS)) diff --git a/test/Transforms/InstSimplify/maxmin.ll b/test/Transforms/InstSimplify/maxmin.ll index 6d92259..707422c 100644 --- a/test/Transforms/InstSimplify/maxmin.ll +++ b/test/Transforms/InstSimplify/maxmin.ll @@ -143,3 +143,91 @@ define i1 @min8(i32 %x, i32 %y) { ret i1 %r ; CHECK: ret i1 true } + +define i1 @maxmin1(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin1 + %c1 = icmp sge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp sge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp sge i32 %max, %min + ret i1 %c +; CHECK: ret i1 true +} + +define i1 @maxmin2(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin2 + %c1 = icmp sge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp sge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp sgt i32 %min, %max + ret i1 %c +; CHECK: ret i1 false +} + +define i1 @maxmin3(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin3 + %c1 = icmp sge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp sge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp sle i32 %min, %max + ret i1 %c +; CHECK: ret i1 true +} + +define i1 @maxmin4(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin4 + %c1 = icmp sge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp sge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp slt i32 %max, %min + ret i1 %c +; CHECK: ret i1 false +} + +define i1 @maxmin5(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin5 + %c1 = icmp uge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp uge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp uge i32 %max, %min + ret i1 %c +; CHECK: ret i1 true +} + +define i1 @maxmin6(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin6 + %c1 = icmp uge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp uge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp ugt i32 %min, %max + ret i1 %c +; CHECK: ret i1 false +} + +define i1 @maxmin7(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin7 + %c1 = icmp uge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp uge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp ule i32 %min, %max + ret i1 %c +; CHECK: ret i1 true +} + +define i1 @maxmin8(i32 %x, i32 %y, i32 %z) { +; CHECK: @maxmin8 + %c1 = icmp uge i32 %x, %y + %max = select i1 %c1, i32 %x, i32 %y + %c2 = icmp uge i32 %x, %z + %min = select i1 %c2, i32 %z, i32 %x + %c = icmp ult i32 %max, %min + ret i1 %c +; CHECK: ret i1 false +} |