From 05bb969014d64611721cd30e4d890f626820ec76 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Mon, 21 Jun 2021 10:49:26 +0100
Subject: [PATCH] [LoopIdiom] Add test case that involves adds with flags and
 zero exts.

Test coverage to ensure D104319 does not introduce a regression here.
---
 .../LoopIdiom/X86/memset-size-compute.ll      | 56 +++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 llvm/test/Transforms/LoopIdiom/X86/memset-size-compute.ll

diff --git a/llvm/test/Transforms/LoopIdiom/X86/memset-size-compute.ll b/llvm/test/Transforms/LoopIdiom/X86/memset-size-compute.ll
new file mode 100644
index 000000000000..57e5376642a1
--- /dev/null
+++ b/llvm/test/Transforms/LoopIdiom/X86/memset-size-compute.ll
@@ -0,0 +1,56 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -loop-idiom -S %s | FileCheck %s
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx11.0.0"
+
+; Make sure the number of bytes is computed correctly in the presence of zero
+; extensions and preserved add flags.
+define void @test(i64* %ptr) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY_PREHEADER:%.*]]
+; CHECK:       dead:
+; CHECK-NEXT:    br label [[FOR_BODY_PREHEADER]]
+; CHECK:       for.body.preheader:
+; CHECK-NEXT:    [[LIM_0:%.*]] = phi i32 [ 65, [[ENTRY:%.*]] ], [ 1, [[DEAD:%.*]] ]
+; CHECK-NEXT:    [[SCEVGEP:%.*]] = getelementptr i64, i64* [[PTR:%.*]], i64 1
+; CHECK-NEXT:    [[SCEVGEP1:%.*]] = bitcast i64* [[SCEVGEP]] to i8*
+; CHECK-NEXT:    [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[LIM_0]], i32 2)
+; CHECK-NEXT:    [[TMP0:%.*]] = add nsw i32 [[UMAX]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = zext i32 [[TMP0]] to i64
+; CHECK-NEXT:    [[TMP2:%.*]] = shl nuw nsw i64 [[TMP1]], 3
+; CHECK-NEXT:    call void @llvm.memset.p0i8.i64(i8* align 8 [[SCEVGEP1]], i8 0, i64 [[TMP2]], i1 false)
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[IV:%.*]] = phi i32 [ [[IV_NEXT:%.*]], [[FOR_BODY]] ], [ 1, [[FOR_BODY_PREHEADER]] ]
+; CHECK-NEXT:    [[IV_EXT:%.*]] = zext i32 [[IV]] to i64
+; CHECK-NEXT:    [[GEP:%.*]] = getelementptr inbounds i64, i64* [[PTR]], i64 [[IV_EXT]]
+; CHECK-NEXT:    [[IV_NEXT]] = add nuw nsw i32 [[IV]], 1
+; CHECK-NEXT:    [[CMP64:%.*]] = icmp ult i32 [[IV_NEXT]], [[LIM_0]]
+; CHECK-NEXT:    br i1 [[CMP64]], label [[FOR_BODY]], label [[EXIT:%.*]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %for.body.preheader
+
+dead:
+  br label %for.body.preheader
+
+for.body.preheader:
+  %lim.0 = phi i32 [ 65, %entry ], [ 1, %dead ]
+  br label %for.body
+
+for.body:
+  %iv = phi i32 [ %iv.next, %for.body ], [ 1, %for.body.preheader ]
+  %iv.ext = zext i32 %iv to i64
+  %gep = getelementptr inbounds i64, i64* %ptr, i64 %iv.ext
+  store i64 0, i64* %gep, align 8
+  %iv.next = add nuw nsw i32 %iv, 1
+  %cmp64 = icmp ult i32 %iv.next, %lim.0
+  br i1 %cmp64, label %for.body, label %exit
+
+exit:
+  ret void
+}