teach SCEV that the scale and addition of an inbounds gep don't NSW.

This fixes a FIXME in scev-aa.ll (allowing a new no-alias result) and
generally makes things more precise.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125449 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 31 insertions, 4 deletions

diff --git a/test/Analysis/ScalarEvolution/nsw.ll b/test/Analysis/ScalarEvolution/nsw.ll
index 010cf604a8..9d8e2b62a9 100644
--- a/test/Analysis/ScalarEvolution/nsw.ll
+++ b/test/Analysis/ScalarEvolution/nsw.ll
@@ -76,3 +76,31 @@ for.cond.for.end_crit_edge.i.i:                   ; preds = %for.body.i.i
 _ZSt4fillIPiiEvT_S1_RKT0_.exit:                   ; preds = %entry, %for.cond.for.end_crit_edge.i.i
   ret void
 }
+
+; Various checks for inbounds geps.
+define void @test3(i32* %begin, i32* %end) nounwind ssp {
+entry:
+  %cmp7.i.i = icmp eq i32* %begin, %end
+  br i1 %cmp7.i.i, label %_ZSt4fillIPiiEvT_S1_RKT0_.exit, label %for.body.i.i
+
+for.body.i.i:                                     ; preds = %entry, %for.body.i.i
+  %indvar.i.i = phi i64 [ %tmp, %for.body.i.i ], [ 0, %entry ]
+; CHECK: %indvar.i.i
+; CHECK: {0,+,1}<nuw><nsw><%for.body.i.i>
+  %tmp = add nsw i64 %indvar.i.i, 1
+; CHECK: %tmp = 
+; CHECK: {1,+,1}<nuw><nsw><%for.body.i.i>
+  %ptrincdec.i.i = getelementptr inbounds i32* %begin, i64 %tmp
+; CHECK: %ptrincdec.i.i =
+; CHECK: {(4 + %begin),+,4}<nsw><%for.body.i.i>
+  %__first.addr.08.i.i = getelementptr inbounds i32* %begin, i64 %indvar.i.i
+; CHECK: %__first.addr.08.i.i
+; CHECK: {%begin,+,4}<nsw><%for.body.i.i>
+  store i32 0, i32* %__first.addr.08.i.i, align 4
+  %cmp.i.i = icmp eq i32* %ptrincdec.i.i, %end
+  br i1 %cmp.i.i, label %_ZSt4fillIPiiEvT_S1_RKT0_.exit, label %for.body.i.i
+; CHECK: Loop %for.body.i.i: Unpredictable backedge-taken count. 
+; CHECK: Loop %for.body.i.i: Unpredictable max backedge-taken count.
+_ZSt4fillIPiiEvT_S1_RKT0_.exit:                   ; preds = %for.body.i.i, %entry
+  ret void
+}
\ No newline at end of file
diff --git a/test/Analysis/ScalarEvolution/scev-aa.ll b/test/Analysis/ScalarEvolution/scev-aa.ll
index 866664a3d6..dd5a66ccb4 100644
--- a/test/Analysis/ScalarEvolution/scev-aa.ll
+++ b/test/Analysis/ScalarEvolution/scev-aa.ll
@@ -190,9 +190,8 @@ define void @bar() {
   ret void
 }
 
-; TODO: This is theoretically provable to be NoAlias.
 ; CHECK: Function: nonnegative: 2 pointers, 0 call sites
-; CHECK: MayAlias:  i64* %arrayidx, i64* %p
+; CHECK: NoAlias:  i64* %arrayidx, i64* %p
 
 define void @nonnegative(i64* %p) nounwind {
 entry:
@@ -211,6 +210,6 @@ for.end:                                          ; preds = %for.body, %entry
   ret void
 }
 
-; CHECK: 13 no alias responses
-; CHECK: 27 may alias responses
+; CHECK: 14 no alias responses
+; CHECK: 26 may alias responses
 ; CHECK: 18 must alias responses