[llvm-commits] [llvm] r132288 - in /llvm/trunk: lib/Transforms/IPO/GlobalOpt.cpp test/Transforms/GlobalOpt/memset-null.ll
Nick Lewycky
nicholas at mxc.ca
Sun May 29 11:41:56 PDT 2011
Author: nicholas
Date: Sun May 29 13:41:56 2011
New Revision: 132288
URL: http://llvm.org/viewvc/llvm-project?rev=132288&view=rev
Log:
Obey the isVolatile bit on memory intrinsics when analyzing uses of a global
variable. Noticed by inspection.
Simulate memset in EvaluateFunction where the target of the memset and the
value we're setting are both the null value. Fixes PR10047!
Added:
llvm/trunk/test/Transforms/GlobalOpt/memset-null.ll
Modified:
llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
Modified: llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp?rev=132288&r1=132287&r2=132288&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/GlobalOpt.cpp Sun May 29 13:41:56 2011
@@ -241,15 +241,15 @@
GS.HasPHIUser = true;
} else if (isa<CmpInst>(I)) {
GS.isCompared = true;
- } else if (isa<MemTransferInst>(I)) {
- const MemTransferInst *MTI = cast<MemTransferInst>(I);
+ } else if (const MemTransferInst *MTI = dyn_cast<MemTransferInst>(I)) {
+ if (MTI->isVolatile()) return true;
if (MTI->getArgOperand(0) == V)
GS.StoredType = GlobalStatus::isStored;
if (MTI->getArgOperand(1) == V)
GS.isLoaded = true;
- } else if (isa<MemSetInst>(I)) {
- assert(cast<MemSetInst>(I)->getArgOperand(0) == V &&
- "Memset only takes one pointer!");
+ } else if (const MemSetInst *MSI = dyn_cast<MemSetInst>(I)) {
+ assert(MSI->getArgOperand(0) == V && "Memset only takes one pointer!");
+ if (MSI->isVolatile()) return true;
GS.StoredType = GlobalStatus::isStored;
} else {
return true; // Any other non-load instruction might take address!
@@ -2438,6 +2438,20 @@
// Cannot handle inline asm.
if (isa<InlineAsm>(CI->getCalledValue())) return false;
+ if (MemSetInst *MSI = dyn_cast<MemSetInst>(CI)) {
+ if (MSI->isVolatile()) return false;
+ Constant *Ptr = getVal(Values, MSI->getDest());
+ Constant *Val = getVal(Values, MSI->getValue());
+ Constant *DestVal = ComputeLoadResult(getVal(Values, Ptr),
+ MutatedMemory);
+ if (Val->isNullValue() && DestVal->isNullValue()) {
+ // This memset is a no-op.
+ ++CurInst;
+ continue;
+ }
+ return false;
+ }
+
// Resolve function pointers.
Function *Callee = dyn_cast<Function>(getVal(Values,
CI->getCalledValue()));
Added: llvm/trunk/test/Transforms/GlobalOpt/memset-null.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/GlobalOpt/memset-null.ll?rev=132288&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/GlobalOpt/memset-null.ll (added)
+++ llvm/trunk/test/Transforms/GlobalOpt/memset-null.ll Sun May 29 13:41:56 2011
@@ -0,0 +1,19 @@
+; RUN: opt -globalopt %s -S -o - | FileCheck %s
+; PR10047
+
+
+%0 = type { i32, void ()* }
+%struct.A = type { [100 x i32] }
+
+; CHECK: @a
+ at a = global %struct.A zeroinitializer, align 4
+ at llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @_GLOBAL__I_a }]
+
+declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind
+
+; CHECK-NOT: GLOBAL__I_a
+define internal void @_GLOBAL__I_a() nounwind {
+entry:
+ tail call void @llvm.memset.p0i8.i64(i8* bitcast (%struct.A* @a to i8*), i8 0, i64 400, i32 4, i1 false) nounwind
+ ret void
+}
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