findDominatingStoreToReturn in CGCall.cpp didn't check if a candidate store

instruction used the ReturnValue as pointer operand or value operand. This
led to wrong code gen - in later stages (load-store elision code) the found
store and its operand would be erased, causing ReturnValue to become a <badref>.

The patch adds a check that makes sure that ReturnValue is a pointer operand of
store instruction. Regression test is also added.

This fixes PR24386.
Differential Revision: http://reviews.llvm.org/D12400

llvm-svn: 247003

1 files changed, 17 insertions, 0 deletions

diff --git a/clang/test/CodeGen/arm_function_epilog.cpp b/clang/test/CodeGen/arm_function_epilog.cpp
new file mode 100644
index 0000000..0089507
--- /dev/null
+++ b/clang/test/CodeGen/arm_function_epilog.cpp
@@ -0,0 +1,17 @@
+// REQUIRES: arm-registered-target
+// RUN: %clang_cc1 -triple armv7-none-linux-androideabi -target-abi aapcs-linux -mfloat-abi hard -x c++ -emit-llvm %s -o - | FileCheck %s
+
+struct Vec2 {
+    union { struct { float x, y; };
+            float data[2];
+    };
+};
+
+// CHECK: define arm_aapcs_vfpcc %struct.Vec2 @_Z7getVec2v()
+// CHECK: ret %struct.Vec2
+Vec2 getVec2() {
+    Vec2 out;
+    union { Vec2* v; unsigned char* u; } x;
+    x.v = &out;
+    return out;
+}