kuhar created this revision.
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kuhar set the repository for this revision to rL LLVM.
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`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.
Repository:
rL LLVM
http://reviews.llvm.org/D12400
Files:
lib/CodeGen/CGCall.cpp
test/CodeGen/arm_function_epilog.cpp
Index: test/CodeGen/arm_function_epilog.cpp
===================================================================
--- /dev/null
+++ 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;
+}
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -2329,6 +2329,7 @@
llvm::StoreInst *store =
dyn_cast<llvm::StoreInst>(CGF.ReturnValue->user_back());
if (!store) return nullptr;
+ if (store->getPointerOperand() != CGF.ReturnValue) return nullptr;
// These aren't actually possible for non-coerced returns, and we
// only care about non-coerced returns on this code path.
Index: test/CodeGen/arm_function_epilog.cpp
===================================================================
--- /dev/null
+++ 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;
+}
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -2329,6 +2329,7 @@
llvm::StoreInst *store =
dyn_cast<llvm::StoreInst>(CGF.ReturnValue->user_back());
if (!store) return nullptr;
+ if (store->getPointerOperand() != CGF.ReturnValue) return nullptr;
// These aren't actually possible for non-coerced returns, and we
// only care about non-coerced returns on this code path.
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