From a7264ff541b12e96cd763322a1a6978542df5aa4 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Mon, 15 Jan 2018 18:20:15 +0000
Subject: [PATCH] Pull in r322473 from upstream llvm trunk (by Andrei
 Elovikov):

  [LV] Don't call recordVectorLoopValueForInductionCast for
  newly-created IV from a trunc.

  Summary:
  This method is supposed to be called for IVs that have casts in their
  use-def chains that are completely ignored after vectorization under
  PSE. However, for truncates of such IVs the same InductionDescriptor
  is used during creation/widening of both original IV based on PHINode
  and new IV based on TruncInst.

  This leads to unintended second call to
  recordVectorLoopValueForInductionCast with a VectorLoopVal set to the
  newly created IV for a trunc and causes an assert due to attempt to
  store new information for already existing entry in the map. This is
  wrong and should not be done.

  Fixes PR35773.

  Reviewers: dorit, Ayal, mssimpso

  Reviewed By: dorit

  Subscribers: RKSimon, dim, dcaballe, hsaito, llvm-commits, hiraditya

  Differential Revision: https://reviews.llvm.org/D41913

This should fix "Vector value already set for part" assertions when
building the net/iodine and sysutils/daa2iso ports.

Reported by:	jbeich
PR:		224867,224868
---
 contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 6ef54385c452..64f206ea92eb 100644
--- a/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/contrib/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2630,9 +2630,12 @@ void InnerLoopVectorizer::createVectorIntOrFpInductionPHI(
   Instruction *LastInduction = VecInd;
   for (unsigned Part = 0; Part < UF; ++Part) {
     VectorLoopValueMap.setVectorValue(EntryVal, Part, LastInduction);
-    recordVectorLoopValueForInductionCast(II, LastInduction, Part);
+
     if (isa<TruncInst>(EntryVal))
       addMetadata(LastInduction, EntryVal);
+    else
+      recordVectorLoopValueForInductionCast(II, LastInduction, Part);
+
     LastInduction = cast<Instruction>(addFastMathFlag(
         Builder.CreateBinOp(AddOp, LastInduction, SplatVF, "step.add")));
   }
@@ -2754,15 +2757,17 @@ void InnerLoopVectorizer::widenIntOrFpInduction(PHINode *IV, TruncInst *Trunc) {
 
   // If we haven't yet vectorized the induction variable, splat the scalar
   // induction variable, and build the necessary step vectors.
+  // TODO: Don't do it unless the vectorized IV is really required.
   if (!VectorizedIV) {
     Value *Broadcasted = getBroadcastInstrs(ScalarIV);
     for (unsigned Part = 0; Part < UF; ++Part) {
       Value *EntryPart =
           getStepVector(Broadcasted, VF * Part, Step, ID.getInductionOpcode());
       VectorLoopValueMap.setVectorValue(EntryVal, Part, EntryPart);
-      recordVectorLoopValueForInductionCast(ID, EntryPart, Part);
       if (Trunc)
         addMetadata(EntryPart, Trunc);
+      else
+        recordVectorLoopValueForInductionCast(ID, EntryPart, Part);
     }
   }