[AArch64] LoopVectorizer test case for cost model to handle signed division by a power of 2

[suyog]

Summary

This is addition to r216371 (SLP and Loop Vectorization) and r218607 where
cost model for signed division by power of 2 was improved for AArch64.

The revision r218607 missed test case for Loop Vectorization.
Adding it here.

Please help in reviewing this patch. I will commit it after the review.

Regards,
Suyog

[mcrosier]

LGTM with one small nit.

test/Transforms/LoopVectorize/AArch64/sdiv-pow2.ll

9 ↗

(On Diff #15953)

I'd prefer a space between the semicolon and the CHECK directive.

[suyog]

Closed by commit rL221674 (authored by @suyog).

[suyog]

Thanks Chad. committed in r221674 with space as per your review.

llvm/trunk/test/Transforms/LoopVectorize/AArch64/sdiv-pow2.ll

+; RUN: opt < %s  -loop-vectorize -mtriple=aarch64-unknown-linux-gnu -mcpu=cortex-a57 -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64--linux-gnu"
+
+%struct.anon = type { [100 x i32], i32, [100 x i32] }
+
+@Foo = common global %struct.anon zeroinitializer, align 4
+
+; CHECK-LABEL: @foo(
+; CHECK: load <4 x i32>*
+; CHECK: sdiv <4 x i32>
+; CHECK: store <4 x i32>
+
+define void @foo(){
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds %struct.anon* @Foo, i64 0, i32 2, i64 %indvars.iv
+  %0 = load i32* %arrayidx, align 4
+  %div = sdiv i32 %0, 2
+  %arrayidx2 = getelementptr inbounds %struct.anon* @Foo, i64 0, i32 0, i64 %indvars.iv
+  store i32 %div, i32* %arrayidx2, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, 100
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}