SLPVectorizer: Fix stale for Value pointer array

We are slicing an array of Value pointers and process those slices in a loop.
The problem is that we might invalidate a later slice by vectorizing a former
slice.

Use a WeakVH to track the pointer. If the pointer is deleted or RAUW'ed we can
tell.

The test case will only fail when running with libgmalloc.

radar://15498655

llvm-svn: 195162

1 files changed, 33 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/X86/rauw-bug.ll b/llvm/test/Transforms/LoopVectorize/X86/rauw-bug.ll
new file mode 100644
index 00000000000..4284fbacfa7
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/X86/rauw-bug.ll
@@ -0,0 +1,33 @@
+; RUN: opt -slp-vectorizer -S %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+; This test used to fail under libgmalloc. Because we would try to access a
+; pointer that was already deleted.
+;
+; llvm-lit -v --param use_gmalloc=1 --param
+;   gmalloc_path=/usr/lib/libgmalloc.dylib
+;   test/Transforms/LoopVectorize/X86/rauw-bug.ll
+;
+; radar://15498655
+
+; CHECK: reduced
+define void @reduced()  {
+entry:
+  br i1 undef, label %while.body, label %while.cond63.preheader.while.end76_crit_edge
+
+while.cond63.preheader.while.end76_crit_edge:
+  ret void
+
+while.body:
+  %d2_fx.015 = phi double [ %sub52, %while.body ], [ undef, %entry ]
+  %d2_fy.014 = phi double [ %sub58, %while.body ], [ undef, %entry ]
+  %d3_fy.013 = phi double [ %div56, %while.body ], [ undef, %entry ]
+  %d3_fx.012 = phi double [ %div50, %while.body ], [ undef, %entry ]
+  %div50 = fmul double %d3_fx.012, 1.250000e-01
+  %sub52 = fsub double 0.000000e+00, %div50
+  %div56 = fmul double %d3_fy.013, 1.250000e-01
+  %sub58 = fsub double 0.000000e+00, %div56
+  br label %while.body
+}