From 6a495073822e3343408d16da2708aa2dd560e929 Mon Sep 17 00:00:00 2001
From: Davide Italiano <davide@freebsd.org>
Date: Thu, 18 May 2017 21:43:23 +0000
Subject: [PATCH] [NewGVN] Replace predicate info leftovers.

This time with an additional fix, i.e. we remove the dead
@llvm.ssa.copy instruction.

llvm-svn: 303385
---
 lib/Transforms/Scalar/NewGVN.cpp  |  6 ++++++
 test/Transforms/NewGVN/pr32945.ll | 24 ++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 test/Transforms/NewGVN/pr32945.ll

diff --git a/lib/Transforms/Scalar/NewGVN.cpp b/lib/Transforms/Scalar/NewGVN.cpp
index 0e7572f8d2e..34b93a88718 100644
--- a/lib/Transforms/Scalar/NewGVN.cpp
+++ b/lib/Transforms/Scalar/NewGVN.cpp
@@ -3301,6 +3301,10 @@ bool NewGVN::eliminateInstructions(Function &F) {
 
           Value *DominatingLeader = EliminationStack.back();
 
+          auto *II = dyn_cast<IntrinsicInst>(DominatingLeader);
+          if (II && II->getIntrinsicID() == Intrinsic::ssa_copy)
+            DominatingLeader = II->getOperand(0);
+
           // Don't replace our existing users with ourselves.
           if (U->get() == DominatingLeader)
             continue;
@@ -3321,6 +3325,8 @@ bool NewGVN::eliminateInstructions(Function &F) {
           // It's about to be alive again.
           if (LeaderUseCount == 0 && isa<Instruction>(DominatingLeader))
             ProbablyDead.erase(cast<Instruction>(DominatingLeader));
+          if (LeaderUseCount == 0 && II)
+            ProbablyDead.insert(II);
           ++LeaderUseCount;
           AnythingReplaced = true;
         }
diff --git a/test/Transforms/NewGVN/pr32945.ll b/test/Transforms/NewGVN/pr32945.ll
new file mode 100644
index 00000000000..553ba4bd4aa
--- /dev/null
+++ b/test/Transforms/NewGVN/pr32945.ll
@@ -0,0 +1,24 @@
+; RUN: opt -S -newgvn %s | FileCheck %s
+; CHECK-NOT: call i32 @llvm.ssa.copy
+
+@d = external global i32
+@e = external global i32
+define void @tinkywinky() {
+  br i1 true, label %lor.lhs.false, label %cond.true
+lor.lhs.false:
+  %tmp = load i32, i32* @d, align 4
+  %patatino = load i32, i32* null, align 4
+  %or = or i32 %tmp, %patatino
+  store i32 %or, i32* @d, align 4
+  br label %cond.true
+cond.true:
+  %tmp1 = load i32, i32* @e, align 4
+  %tmp2 = load i32, i32* @d, align 4
+  %cmp = icmp eq i32 %tmp1, %tmp2
+  br i1 %cmp, label %cond.true6, label %cond.false
+cond.true6:
+  %cmp7 = icmp slt i32 %tmp1, 0
+  br i1 %cmp7, label %cond.false, label %cond.false
+cond.false:
+  ret void
+}