[TransformWarning] Do not warn missed transformations in optnone functions.

Optimization transformations are intentionally disabled by the 'optnone'
function attribute. Therefore do not warn if transformation metadata is
still present.

Using the legacy pass manager structure, the `skipFunction` method takes
care for the optnone attribute (already called before this patch). For
the new pass manager, there is no equivalent, so we check for the
'optnone' attribute manually.

Differential Revision: https://reviews.llvm.org/D55690

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@349184 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Meinersbur

lib/Transforms/Scalar/WarnMissedTransforms.cpp

@@ -91,6 +91,11 @@ static void warnAboutLeftoverTransformations(Function *F, LoopInfo *LI,
 // New pass manager boilerplate
 PreservedAnalyses
 WarnMissedTransformationsPass::run(Function &F, FunctionAnalysisManager &AM) {
+  // Do not warn about not applied transformations if optimizations are
+  // disabled.
+  if (F.hasFnAttribute(Attribute::OptimizeNone))
+    return PreservedAnalyses::all();
+
   auto &ORE = AM.getResult<OptimizationRemarkEmitterAnalysis>(F);
   auto &LI = AM.getResult<LoopAnalysis>(F);
 

test/Transforms/LoopTransformWarning/optnone.ll

@@ -0,0 +1,50 @@
+; Legacy pass manager
+; RUN: opt -transform-warning -disable-output -pass-remarks-missed=transform-warning -pass-remarks-analysis=transform-warning < %s 2>&1 | FileCheck -allow-empty %s
+;
+; New pass manager
+; RUN: opt -passes=transform-warning -disable-output -pass-remarks-missed=transform-warning -pass-remarks-analysis=transform-warning < %s 2>&1 | FileCheck -allow-empty %s
+;
+; Verify that no transformation warnings are emitted for functions with
+; 'optnone' attribute.
+;
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @func(i32* nocapture %A, i32* nocapture readonly %B, i32 %Length) #0 {
+entry:
+  %cmp9 = icmp sgt i32 %Length, 0
+  br i1 %cmp9, label %for.body.preheader, label %for.end
+
+for.body.preheader:
+  br label %for.body
+
+for.body:
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.body ], [ 0, %for.body.preheader ]
+  %arrayidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
+  %0 = load i32, i32* %arrayidx, align 4
+  %idxprom1 = sext i32 %0 to i64
+  %arrayidx2 = getelementptr inbounds i32, i32* %A, i64 %idxprom1
+  %1 = load i32, i32* %arrayidx2, align 4
+  %arrayidx4 = getelementptr inbounds i32, i32* %A, i64 %indvars.iv
+  store i32 %1, i32* %arrayidx4, align 4
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %Length
+  br i1 %exitcond, label %for.end.loopexit, label %for.body, !llvm.loop !0
+
+for.end.loopexit:
+  br label %for.end
+
+for.end:
+  ret void
+}
+
+attributes #0 = { noinline optnone }
+
+!0 = distinct !{!0, !1, !2, !3}
+!1 = !{!"llvm.loop.unroll.enable"}
+!2 = !{!"llvm.loop.distribute.enable"}
+!3 = !{!"llvm.loop.unroll_and_jam.enable"}
+!4 = !{!"llvm.loop.vectorize.enable", i1 true}
+
+
+; CHECK-NOT: warning