[SCEV] Introduce add operation inlining limit

Inlining in getAddExpr() can cause abnormal computational time in some cases.
New parameter -scev-addops-inline-threshold is intruduced with default value 500.

Reviewers: sanjoy

Subscribers: mzolotukhin, llvm-commits

Differential Revision: https://reviews.llvm.org/D28812

llvm-svn: 293176

1 files changed, 17 insertions, 0 deletions

diff --git a/llvm/test/Analysis/ScalarEvolution/max-addops-inline.ll b/llvm/test/Analysis/ScalarEvolution/max-addops-inline.ll
new file mode 100644
index 00000000000..2701ed32839
--- /dev/null
+++ b/llvm/test/Analysis/ScalarEvolution/max-addops-inline.ll
@@ -0,0 +1,17 @@
+; RUN: opt -analyze -scalar-evolution -scev-addops-inline-threshold=1 < %s | FileCheck --check-prefix=CHECK1 %s
+; RUN: opt -analyze -scalar-evolution -scev-addops-inline-threshold=10 < %s | FileCheck --check-prefix=CHECK10 %s
+
+define i32 @foo(i64 %p0, i32 %p1) {
+; CHECK1: %add2 = add nsw i32 %mul1, %add
+; CHECK1-NEXT: -->  ((trunc i64 %p0 to i32) * (1 + (trunc i64 %p0 to i32)) * (1 + %p1))
+
+; CHECK10: %add2 = add nsw i32 %mul1, %add
+; CHECK10-NEXT: -->  ((trunc i64 %p0 to i32) * (1 + ((trunc i64 %p0 to i32) * (1 + %p1)) + %p1))
+entry:
+  %tr = trunc i64 %p0 to i32
+  %mul = mul nsw i32 %tr, %p1
+  %add = add nsw i32 %mul, %tr
+  %mul1 = mul nsw i32 %add, %tr
+  %add2 = add nsw i32 %mul1, %add
+  ret i32 %add2
+}