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

diff --git a/lib/Transforms/Scalar/SROA.cpp b/lib/Transforms/Scalar/SROA.cpp
index b3e63ae355d7d755b0202e4b48d72d9b2d7a58ab..c33ee8fb8756025cb94fb8ca6b09004bf5557876 100644 (file)
--- 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 a61de05f45018f7682bb36c13fa25664ae981c04..359a56a00d56b89693bd9c51ac4fd709c1de7028 100644 (file)
--- 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
+}