Don't try to emit loopVectorize warning if DebugLoc isn't available

[davide]

Summary

This is a (hopefullly) reasonable attempt to fix PR23380
https://llvm.org/bugs/show_bug.cgi?id=23380

[nadav]

Looks good to me.

[dexonsmith]

Would it be better to make emitOptimizationRemarkMissed() resilient to a null DebugLoc? It seems strange to require debug info to print pass remarks.

• dpnes

[davide]

In D9463#165235, @dexonsmith wrote:

Would it be better to make emitOptimizationRemarkMissed() resilient to a null DebugLoc? It seems strange to require debug info to print pass remarks.

emitLoopVectorizeWarning() should actually be made resilient because that's where the crash happen.
I'll take a look at this further tomorrow.

[gberry]

Coincidentally, I just submitted a patch to do this in clang:

http://reviews.llvm.org/D9449

Geoff Berry
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux
Foundation Collaborative Project

[davide]

D9499 landed and fixed the problem. After discussion with dexonsmith on IRC we agreed it's better to emit the remark all the time, hence this review can be abandoned.

lib/Transforms/Vectorize/LoopVectorize.cpp

   }
 
   /// The loop these hints belong to.
   const Loop *TheLoop;
 };
 
 static void emitMissedWarning(Function *F, Loop *L,
                               const LoopVectorizeHints &LH) {
+  DebugLoc DL = L->getStartLoc();
+  if (!DL)
+    return;
   emitOptimizationRemarkMissed(F->getContext(), DEBUG_TYPE, *F,
-                               L->getStartLoc(), LH.emitRemark());
+                               DL, LH.emitRemark());
 
   if (LH.getForce() == LoopVectorizeHints::FK_Enabled) {
     if (LH.getWidth() != 1)
       emitLoopVectorizeWarning(
-          F->getContext(), *F, L->getStartLoc(),
+          F->getContext(), *F, DL,
           "failed explicitly specified loop vectorization");
     else if (LH.getInterleave() != 1)
       emitLoopInterleaveWarning(
-          F->getContext(), *F, L->getStartLoc(),
+          F->getContext(), *F, DL,
           "failed explicitly specified loop interleaving");
   }
 }
 
 static void addInnerLoop(Loop &L, SmallVectorImpl<Loop *> &V) {
   if (L.empty())
     return V.push_back(&L);