From 022cc6c41e3711c61a86f12ab7bea010ad72ed88 Mon Sep 17 00:00:00 2001
From: Alexey Bataev <a.bataev@hotmail.com>
Date: Wed, 27 Sep 2017 17:42:49 +0000
Subject: [SLP] Fix crash on propagate IR flags for undef operands of min/max
 reductions.

If both operands of the newly created SelectInst are Undefs the
resulting operation is also Undef, not SelectInst. It may cause crashes
when trying to propagate IR flags because function expects exactly
SelectInst instruction, nothing else.

llvm-svn: 314323
---
 llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

(limited to 'llvm/lib/Transforms/Vectorize')

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 7f767dcc7d6..d201387debd 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -4938,7 +4938,8 @@ class HorizontalReduction {
       case RK_Max:
       case RK_UMin:
       case RK_UMax:
-        propagateIRFlags(cast<SelectInst>(Op)->getCondition(), ReductionOps[0]);
+        if (auto *SI = dyn_cast<SelectInst>(Op))
+          propagateIRFlags(SI->getCondition(), ReductionOps[0]);
         propagateIRFlags(Op, ReductionOps[1]);
         return Op;
       case RK_None:
@@ -4961,8 +4962,10 @@ class HorizontalReduction {
       case RK_Max:
       case RK_UMin:
       case RK_UMax:
-        propagateIRFlags(cast<SelectInst>(Op)->getCondition(),
-                         cast<SelectInst>(I)->getCondition());
+        if (auto *SI = dyn_cast<SelectInst>(Op)) {
+          propagateIRFlags(SI->getCondition(),
+                           cast<SelectInst>(I)->getCondition());
+        }
         propagateIRFlags(Op, I);
         return Op;
       case RK_None:
-- 
cgit v1.2.3