From 8cc9a8c7d2990a77ab065822c26443ea6e0fbfa7 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans@hanshq.net>
Date: Tue, 5 Feb 2019 12:51:49 +0000
Subject: [PATCH] Merging r353082:
 ------------------------------------------------------------------------
 r353082 | meinersbur | 2019-02-04 20:55:59 +0100 (Mon, 04 Feb 2019) | 10
 lines

[WarnMissedTransforms] Do not warn about already vectorized loops.

LoopVectorize adds llvm.loop.isvectorized, but leaves
llvm.loop.vectorize.enable. Do not consider such a loop for user-forced
vectorization since vectorization already happened -- by prioritizing
llvm.loop.isvectorized except for TM_SuppressedByUser.

Fixes http://llvm.org/PR40546

Differential Revision: https://reviews.llvm.org/D57542
------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_80@353166 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/LoopUtils.cpp            | 14 ++++----
 .../enable_and_isvectorized.ll                | 33 +++++++++++++++++++
 2 files changed, 40 insertions(+), 7 deletions(-)
 create mode 100644 test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll

diff --git a/lib/Transforms/Utils/LoopUtils.cpp b/lib/Transforms/Utils/LoopUtils.cpp
index a93d1aeb62e..4bc353989ef 100644
--- a/lib/Transforms/Utils/LoopUtils.cpp
+++ b/lib/Transforms/Utils/LoopUtils.cpp
@@ -376,17 +376,17 @@ TransformationMode llvm::hasVectorizeTransformation(Loop *L) {
   Optional<int> InterleaveCount =
       getOptionalIntLoopAttribute(L, "llvm.loop.interleave.count");
 
-  if (Enable == true) {
-    // 'Forcing' vector width and interleave count to one effectively disables
-    // this tranformation.
-    if (VectorizeWidth == 1 && InterleaveCount == 1)
-      return TM_SuppressedByUser;
-    return TM_ForcedByUser;
-  }
+  // 'Forcing' vector width and interleave count to one effectively disables
+  // this tranformation.
+  if (Enable == true && VectorizeWidth == 1 && InterleaveCount == 1)
+    return TM_SuppressedByUser;
 
   if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized"))
     return TM_Disable;
 
+  if (Enable == true)
+    return TM_ForcedByUser;
+
   if (VectorizeWidth == 1 && InterleaveCount == 1)
     return TM_Disable;
 
diff --git a/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll b/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll
new file mode 100644
index 00000000000..77d09ad53f7
--- /dev/null
+++ b/test/Transforms/LoopTransformWarning/enable_and_isvectorized.ll
@@ -0,0 +1,33 @@
+; RUN: opt -transform-warning -disable-output < %s 2>&1 | FileCheck -allow-empty %s
+;
+; llvm.org/PR40546
+; Do not warn about about leftover llvm.loop.vectorize.enable for already
+; vectorized loops.
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @test(i32 %n) {
+entry:
+  %cmp = icmp eq i32 %n, 0
+  br i1 %cmp, label %simd.if.end, label %omp.inner.for.body.preheader
+
+omp.inner.for.body.preheader:
+  %wide.trip.count = zext i32 %n to i64
+  br label %omp.inner.for.body
+
+omp.inner.for.body:
+  %indvars.iv = phi i64 [ 0, %omp.inner.for.body.preheader ], [ %indvars.iv.next, %omp.inner.for.body ]
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
+  br i1 %exitcond, label %simd.if.end, label %omp.inner.for.body, !llvm.loop !0
+
+simd.if.end:
+  ret void
+}
+
+!0 = distinct !{!0, !1, !2}
+!1 = !{!"llvm.loop.vectorize.enable", i1 true}
+!2 = !{!"llvm.loop.isvectorized"}
+
+
+; CHECK-NOT: loop not vectorized
-- 
2.40.0