[llvm] r257134 - [Vectorization] Actually return from error case in isStridedPtr

[Kyle Butt via llvm-commits]

Author: iteratee
Date: Thu Jan  7 19:55:13 2016
New Revision: 257134

URL: http://llvm.org/viewvc/llvm-project?rev=257134&view=rev
Log:
[Vectorization] Actually return from error case in isStridedPtr

The early return seems to be missed. This causes a radical and wrong loop
optimization on powerpc. It isn't reproducible on x86_64, because
"UseInterleaved" is false.

Patch by Tim Shen.

Added:
    llvm/trunk/test/Analysis/LoopAccessAnalysis/interleave-innermost.ll
Modified:
    llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp

Modified: llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp?rev=257134&r1=257133&r2=257134&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/LoopAccessAnalysis.cpp Thu Jan  7 19:55:13 2016
@@ -845,6 +845,7 @@ int llvm::isStridedPtr(PredicatedScalarE
   if (Lp != AR->getLoop()) {
     DEBUG(dbgs() << "LAA: Bad stride - Not striding over innermost loop " <<
           *Ptr << " SCEV: " << *PtrScev << "\n");
+    return 0;
   }
 
   // The address calculation must not wrap. Otherwise, a dependence could be

Added: llvm/trunk/test/Analysis/LoopAccessAnalysis/interleave-innermost.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/LoopAccessAnalysis/interleave-innermost.ll?rev=257134&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/LoopAccessAnalysis/interleave-innermost.ll (added)
+++ llvm/trunk/test/Analysis/LoopAccessAnalysis/interleave-innermost.ll Thu Jan  7 19:55:13 2016
@@ -0,0 +1,29 @@
+; RUN: opt -loop-vectorize -force-vector-interleave=1 -S < %s | FileCheck %s
+; CHECK-LABEL: TestFoo
+; CHECK-NOT: %wide.vec
+
+target datalayout = "e-m:e-i64:64-n32:64"
+target triple = "powerpc64le-unknown-linux-gnu"
+
+define void @TestFoo(i1 %X, i1 %Y) {
+bb:
+  br label %.loopexit5.outer
+
+.loopexit5.outer:
+  br label %.lr.ph12
+
+.loopexit:
+  br i1 %X, label %.loopexit5.outer, label %.lr.ph12
+
+.lr.ph12:
+  %f.110 = phi i32* [ %tmp1, %.loopexit ], [ null, %.loopexit5.outer ]
+  %tmp1 = getelementptr inbounds i32, i32* %f.110, i64 -2
+  br i1 %Y, label %bb4, label %.loopexit
+
+bb4:
+  %j.27 = phi i32 [ 0, %.lr.ph12 ], [ %tmp7, %bb4 ]
+  %tmp5 = load i32, i32* %f.110, align 4
+  %tmp7 = add nsw i32 %j.27, 1
+  %exitcond = icmp eq i32 %tmp7, 0
+  br i1 %exitcond, label %.loopexit, label %bb4
+}