LoopVectorizer: integer division is not a reduction operation

[oota-llvm.git] / test / Transforms / LoopVectorize / no_idiv_reduction.ll

diff --git a/test/Transforms/LoopVectorize/no_idiv_reduction.ll b/test/Transforms/LoopVectorize/no_idiv_reduction.ll
new file mode 100644 (file)
index 0000000..cdfb3fd
--- /dev/null
+++ b/test/Transforms/LoopVectorize/no_idiv_reduction.ll
@@ -0,0 +1,24 @@
+; RUN: opt -loop-vectorize -force-vector-width=2 -force-vector-unroll=1 -S < %s | FileCheck %s
+@a = common global [128 x i32] zeroinitializer, align 16
+
+;; Must not vectorize division reduction. Division is lossy.
+define i32 @g() {
+entry:
+  br label %for.body
+
+for.body:
+  ; CHECK: @g
+  ; CHECK-NOT: sdiv <2 x i32>
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %r.05 = phi i32 [ 80, %entry ], [ %div, %for.body ]
+  %arrayidx = getelementptr inbounds [128 x i32]* @a, i64 0, i64 %indvars.iv
+  %0 = load i32* %arrayidx, align 4
+  %div = sdiv i32 %r.05, %0
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, 1024
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret i32 %div
+}