cl::desc("Maximum depth of recursive SExt/ZExt"),
cl::init(8));
+static cl::opt<unsigned>
+ MaxAddRecSize("scalar-evolution-max-add-rec-size", cl::Hidden,
+ cl::desc("Max coefficients in AddRec during evolving"),
+ cl::init(16));
+
//===----------------------------------------------------------------------===//
// SCEV class definitions
//===----------------------------------------------------------------------===//
if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop)
continue;
+ // Limit max number of arguments to avoid creation of unreasonably big
+ // SCEVAddRecs with very complex operands.
+ if (AddRec->getNumOperands() + OtherAddRec->getNumOperands() - 1 >
+ MaxAddRecSize)
+ continue;
+
bool Overflow = false;
Type *Ty = AddRec->getType();
bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64;
--- /dev/null
+; RUN: opt -analyze -scalar-evolution -scalar-evolution-max-add-rec-size=3 < %s | FileCheck %s
+
+; Show that we are able to avoid creation of huge SCEVs by capping the max
+; AddRec size.
+define i32 @test_01(i32 %a, i32 %b) {
+
+; CHECK-LABEL: Classifying expressions for: @test_01
+; CHECK-NEXT: %iv = phi i32 [ %a, %entry ], [ %iv.next, %loop ]
+; CHECK-NEXT: --> {%a,+,%b}<%loop> U: full-set S: full-set
+; CHECK-NEXT: %iv.next = add i32 %iv, %b
+; CHECK-NEXT: --> {(%a + %b),+,%b}<%loop> U: full-set S: full-set
+; CHECK-NEXT: %x1 = mul i32 %iv, %iv.next
+; CHECK-NEXT: --> {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> U: full-set S: full-set
+; CHECK-NEXT: %x2 = mul i32 %x1, %x1
+; CHECK-NEXT: --> ({((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop>) U: full-set S: full-set
+; CHECK-NEXT: %x3 = mul i32 %x2, %x1
+; CHECK-NEXT: --> ({((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop>) U: full-set S: full-set
+
+entry:
+ br label %loop
+
+loop:
+ %iv = phi i32 [ %a, %entry ], [ %iv.next, %loop ]
+ %iv.next = add i32 %iv, %b
+ %cond = icmp slt i32 %iv.next, 1000
+ br i1 %cond, label %loop, label %exit
+
+exit:
+ %x1 = mul i32 %iv, %iv.next
+ %x2 = mul i32 %x1, %x1
+ %x3 = mul i32 %x2, %x1
+ ret i32 %x3
+}