ret void
; CHECK: ret void
}
+
+; Recognize loops with a negative stride.
+define void @test15(i32* nocapture %f) {
+entry:
+ br label %for.body
+
+for.body:
+ %indvars.iv = phi i64 [ 65536, %entry ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %f, i64 %indvars.iv
+ store i32 0, i32* %arrayidx, align 4
+ %indvars.iv.next = add nsw i64 %indvars.iv, -1
+ %cmp = icmp sgt i64 %indvars.iv, 0
+ br i1 %cmp, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup:
+ ret void
+; CHECK-LABEL: @test15(
+; CHECK: call void @llvm.memset.p0i8.i64(i8* %f1, i8 0, i64 262148, i32 4, i1 false)
+; CHECK-NOT: store
+; CHECK: ret void
+}
+
+; Loop with a negative stride. Verify an aliasing write to f[65536] prevents
+; the creation of a memset.
+define void @test16(i32* nocapture %f) {
+entry:
+ %arrayidx1 = getelementptr inbounds i32, i32* %f, i64 65536
+ br label %for.body
+
+for.body: ; preds = %entry, %for.body
+ %indvars.iv = phi i64 [ 65536, %entry ], [ %indvars.iv.next, %for.body ]
+ %arrayidx = getelementptr inbounds i32, i32* %f, i64 %indvars.iv
+ store i32 0, i32* %arrayidx, align 4
+ store i32 1, i32* %arrayidx1, align 4
+ %indvars.iv.next = add nsw i64 %indvars.iv, -1
+ %cmp = icmp sgt i64 %indvars.iv, 0
+ br i1 %cmp, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup: ; preds = %for.body
+ ret void
+; CHECK-LABEL: @test16(
+; CHECK-NOT: call void @llvm.memset.p0i8.i64
+; CHECK: ret void
+}