[SCEV] Strengthen StrengthenNoWrapFlags (reapply r334428).

Summary:
Comment on Transforms/LoopVersioning/incorrect-phi.ll: With the change
SCEV is able to prove that the loop doesn't wrap-self (due to zext i16
to i64), disabling the entire loop versioning pass. Removed the zext and
just use i64.

Reviewers: sanjoy

Subscribers: jlebar, hiraditya, javed.absar, bixia, llvm-commits

Differential Revision: https://reviews.llvm.org/D48409

llvm-svn: 336140

1 files changed, 10 insertions, 6 deletions

diff --git a/llvm/test/Analysis/ScalarEvolution/zext-mul.ll b/llvm/test/Analysis/ScalarEvolution/zext-mul.ll
index ae93a9288d8..0c0f16c1dea 100644
--- a/llvm/test/Analysis/ScalarEvolution/zext-mul.ll
+++ b/llvm/test/Analysis/ScalarEvolution/zext-mul.ll
@@ -19,16 +19,20 @@ define void @no_range() {
 }
 
 ; CHECK-LABEL: @range
-;
-; This had to be disabled when r334428 was reverted.  We should enable this test
-; when r334428 is reapplied with a fix.
 define void @range() {
-  %a = call i32 @get_int(), !range !0
+  %a = call i32 @get_int(), !range !{i32 0, i32 100}
   %b = mul i32 %a, 4
   %c = zext i32 %b to i64
   ; CHECK: %c
-  ; CHECK-NEXT: --> (zext i32 (4 * %a) to i64)
+  ; CHECK-NEXT: --> (4 * (zext i32 %a to i64))<nuw><nsw>
   ret void
 }
 
-!0 = !{i32 0, i32 100}
+; CHECK-LABEL: @no_nuw
+define void @no_nuw() {
+  %a = call i32 @get_int(), !range !{i32 0, i32 3}
+  %b = mul i32 %a, -100
+  ; CHECK: %b
+  ; CHECK-NEXT: -->  (-100 * %a)<nsw>
+  ret void
+}