r247003 - findDominatingStoreToReturn in CGCall.cpp didn't check if a candidate store
Jakub Kuderski via cfe-commits
cfe-commits at lists.llvm.org
Tue Sep 8 03:36:42 PDT 2015
Author: kuhar
Date: Tue Sep 8 05:36:42 2015
New Revision: 247003
URL: http://llvm.org/viewvc/llvm-project?rev=247003&view=rev
Log:
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
Added:
cfe/trunk/test/CodeGen/arm_function_epilog.cpp
Modified:
cfe/trunk/lib/CodeGen/CGCall.cpp
Modified: cfe/trunk/lib/CodeGen/CGCall.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=247003&r1=247002&r2=247003&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGCall.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGCall.cpp Tue Sep 8 05:36:42 2015
@@ -2259,6 +2259,18 @@ static llvm::Value *emitAutoreleaseOfRes
/// Heuristically search for a dominating store to the return-value slot.
static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) {
+ // Check if a User is a store which pointerOperand is the ReturnValue.
+ // We are looking for stores to the ReturnValue, not for stores of the
+ // ReturnValue to some other location.
+ auto GetStoreIfValid = [&CGF](llvm::User *U) -> llvm::StoreInst * {
+ auto *SI = dyn_cast<llvm::StoreInst>(U);
+ if (!SI || SI->getPointerOperand() != CGF.ReturnValue.getPointer())
+ return nullptr;
+ // These aren't actually possible for non-coerced returns, and we
+ // only care about non-coerced returns on this code path.
+ assert(!SI->isAtomic() && !SI->isVolatile());
+ return SI;
+ };
// If there are multiple uses of the return-value slot, just check
// for something immediately preceding the IP. Sometimes this can
// happen with how we generate implicit-returns; it can also happen
@@ -2287,22 +2299,13 @@ static llvm::StoreInst *findDominatingSt
break;
}
- llvm::StoreInst *store = dyn_cast<llvm::StoreInst>(I);
- if (!store) return nullptr;
- if (store->getPointerOperand() != CGF.ReturnValue.getPointer())
- return nullptr;
- assert(!store->isAtomic() && !store->isVolatile()); // see below
- return store;
+ return GetStoreIfValid(I);
}
llvm::StoreInst *store =
- dyn_cast<llvm::StoreInst>(CGF.ReturnValue.getPointer()->user_back());
+ GetStoreIfValid(CGF.ReturnValue.getPointer()->user_back());
if (!store) return nullptr;
- // These aren't actually possible for non-coerced returns, and we
- // only care about non-coerced returns on this code path.
- assert(!store->isAtomic() && !store->isVolatile());
-
// Now do a first-and-dirty dominance check: just walk up the
// single-predecessors chain from the current insertion point.
llvm::BasicBlock *StoreBB = store->getParent();
Added: cfe/trunk/test/CodeGen/arm_function_epilog.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/arm_function_epilog.cpp?rev=247003&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/arm_function_epilog.cpp (added)
+++ cfe/trunk/test/CodeGen/arm_function_epilog.cpp Tue Sep 8 05:36:42 2015
@@ -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;
+}
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