Fix PR16797 - Support PHINodes with multiple inputs from the same basic block.

Do not generate new vector values for the same entries because we know that the incoming values
from the same block must be identical.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188185 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Vectorize/SLPVectorizer.cpp b/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 9312b4bb4b07f914fd95585c55d8e8dea96f5932..22a2519d67f52882e76ad10f61133848890573f0 100644 (file)
--- a/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -1187,10 +1187,21 @@ Value *BoUpSLP::vectorizeTree(TreeEntry *E) {
       PHINode *NewPhi = Builder.CreatePHI(VecTy, PH->getNumIncomingValues());
       E->VectorizedValue = NewPhi;
 
+      // PHINodes may have multiple entries from the same block. We want to
+      // visit every block once.
+      SmallSet<BasicBlock*, 4> VisitedBBs;
+
       for (unsigned i = 0, e = PH->getNumIncomingValues(); i < e; ++i) {
         ValueList Operands;
         BasicBlock *IBB = PH->getIncomingBlock(i);
 
+        if (VisitedBBs.count(IBB)) {
+          NewPhi->addIncoming(NewPhi->getIncomingValueForBlock(IBB), IBB);
+          continue;
+        }
+
+        VisitedBBs.insert(IBB);
+
         // Prepare the operand vector.
         for (unsigned j = 0; j < E->Scalars.size(); ++j)
           Operands.push_back(cast<PHINode>(E->Scalars[j])->

diff --git a/test/Transforms/SLPVectorizer/X86/crash_netbsd_decompress.ll b/test/Transforms/SLPVectorizer/X86/crash_netbsd_decompress.ll
new file mode 100644 (file)
index 0000000..8da3c34
--- /dev/null
+++ b/test/Transforms/SLPVectorizer/X86/crash_netbsd_decompress.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -basicaa -slp-vectorizer -dce -S -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7
+
+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-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+%struct.DState = type { i32, i32 }
+
+@b = common global %struct.DState zeroinitializer, align 4
+@d = common global i32 0, align 4
+@c = common global i32 0, align 4
+@a = common global i32 0, align 4
+@e = common global i32 0, align 4
+
+define i32 @fn1() {
+entry:
+  %0 = load i32* getelementptr inbounds (%struct.DState* @b, i32 0, i32 0), align 4
+  %1 = load i32* getelementptr inbounds (%struct.DState* @b, i32 0, i32 1), align 4
+  %2 = load i32* @d, align 4
+  %cond = icmp eq i32 %2, 0
+  br i1 %cond, label %sw.bb, label %save_state_and_return
+
+sw.bb:                                            ; preds = %entry
+  %3 = load i32* @c, align 4
+  %and = and i32 %3, 7
+  store i32 %and, i32* @a, align 4
+  switch i32 %and, label %if.end [
+    i32 7, label %save_state_and_return
+    i32 0, label %save_state_and_return
+  ]
+
+if.end:                                           ; preds = %sw.bb
+  br label %save_state_and_return
+
+save_state_and_return:                            ; preds = %sw.bb, %sw.bb, %if.end, %entry
+  %t.0 = phi i32 [ 0, %if.end ], [ %0, %entry ], [ %0, %sw.bb ], [ %0, %sw.bb ]
+  %f.0 = phi i32 [ 0, %if.end ], [ %1, %entry ], [ 0, %sw.bb ], [ 0, %sw.bb ]
+  store i32 %t.0, i32* getelementptr inbounds (%struct.DState* @b, i32 0, i32 0), align 4
+  store i32 %f.0, i32* getelementptr inbounds (%struct.DState* @b, i32 0, i32 1), align 4
+  ret i32 undef
+}
+