From c3f10e43fc4b1084bc109ff740d9ba4b6eaced0a Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nicholas@mxc.ca>
Date: Tue, 25 Sep 2012 21:15:50 +0000
Subject: [PATCH] Don't try to promote the same alloca twice. Fixes PR13916!

Chandler, it's not obvious that it's okay that this alloca gets into the list
twice to begin with. Please review and see whether this is the fix you really
want, but I wanted to get a fix checked in quickly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164634 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/SROA.cpp    |  6 ++++++
 test/Transforms/SROA/basictest.ll | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/lib/Transforms/Scalar/SROA.cpp b/lib/Transforms/Scalar/SROA.cpp
index b3e63ae355d..c33ee8fb875 100644
--- a/lib/Transforms/Scalar/SROA.cpp
+++ b/lib/Transforms/Scalar/SROA.cpp
@@ -3108,6 +3108,12 @@ bool SROA::promoteAllocas(Function &F) {
   if (PromotableAllocas.empty())
     return false;
 
+  // Ensure that the list is unique.
+  std::sort(PromotableAllocas.begin(), PromotableAllocas.end());
+  PromotableAllocas.erase(std::unique(PromotableAllocas.begin(),
+                                      PromotableAllocas.end()),
+                          PromotableAllocas.end());
+
   NumPromoted += PromotableAllocas.size();
 
   if (DT && !ForceSSAUpdater) {
diff --git a/test/Transforms/SROA/basictest.ll b/test/Transforms/SROA/basictest.ll
index a61de05f450..359a56a00d5 100644
--- a/test/Transforms/SROA/basictest.ll
+++ b/test/Transforms/SROA/basictest.ll
@@ -855,3 +855,25 @@ entry:
   %result = or i8 %load, %load2
   ret i8 %result
 }
+
+%test22.struct = type { i8 }
+
+define void @test22() {
+; CHECK: @test22
+; CHECK-NOT: alloca
+; CHECK: ret void
+; PR13916
+entry:
+  %A = alloca %test22.struct
+  br i1 undef, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  %tmp = bitcast %test22.struct* %A to i8*
+  %tmp1 = bitcast %test22.struct* %A to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* %tmp1, i32 1, i32 1, i1 false)
+  unreachable
+
+if.end:                                           ; preds = %entry
+  %tmp2 = load %test22.struct* %A
+  ret void
+}