[SROA] Fix PR24463, a crash I introduced in SROA by allowing it to

[oota-llvm.git] / test / Transforms / SROA / basictest.ll

diff --git a/test/Transforms/SROA/basictest.ll b/test/Transforms/SROA/basictest.ll
index 009f16a80bb77970872f55646a91fbcb9b0aa010..25b8e8ba41fc1b5bd867166b03d04b9523baa36c 100644 (file)
--- a/test/Transforms/SROA/basictest.ll
+++ b/test/Transforms/SROA/basictest.ll
@@ -1609,3 +1609,26 @@ entry:
   %load = load atomic volatile i64, i64* %ptr seq_cst, align 8
   ret void
 }
+
+define i16 @PR24463() {
+; Ensure we can handle a very interesting case where there is an integer-based
+; rewrite of the uses of the alloca, but where one of the integers in that is
+; a sub-integer that requires extraction *and* extends past the end of the
+; alloca. In this case, we should extract the i8 and then zext it to i16.
+;
+; CHECK-LABEL @PR24463(
+; CHECK-NOT: alloca
+; CHECK: %[[SHIFT:.*]] = lshr i16 0, 8
+; CHECK: %[[TRUNC:.*]] = trunc i16 %[[SHIFT]] to i8
+; CHECK: %[[ZEXT:.*]] = zext i8 %[[TRUNC]] to i16
+; CHECK: ret i16 %[[ZEXT]]
+entry:
+  %alloca = alloca [3 x i8]
+  %gep1 = getelementptr inbounds [3 x i8], [3 x i8]* %alloca, i64 0, i64 1
+  %bc1 = bitcast i8* %gep1 to i16*
+  store i16 0, i16* %bc1
+  %gep2 = getelementptr inbounds [3 x i8], [3 x i8]* %alloca, i64 0, i64 2
+  %bc2 = bitcast i8* %gep2 to i16*
+  %load = load i16, i16* %bc2
+  ret i16 %load
+}