[llvm-commits] [llvm] r90045 - in /llvm/trunk: lib/Analysis/MemoryDependenceAnalysis.cpp test/Transforms/DeadStoreElimination/lifetime.ll
Nick Lewycky
nicholas at mxc.ca
Sat Nov 28 13:27:49 PST 2009
Author: nicholas
Date: Sat Nov 28 15:27:49 2009
New Revision: 90045
URL: http://llvm.org/viewvc/llvm-project?rev=90045&view=rev
Log:
Teach memdep to look for memory use intrinsics during dependency queries. Fixes
PR5574.
Modified:
llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
llvm/trunk/test/Transforms/DeadStoreElimination/lifetime.ll
Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=90045&r1=90044&r2=90045&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Sat Nov 28 15:27:49 2009
@@ -201,7 +201,7 @@
// If we reach a lifetime begin or end marker, then the query ends here
// because the value is undefined.
} else if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
- II->getIntrinsicID() == Intrinsic::lifetime_end) {
+ II->getIntrinsicID() == Intrinsic::lifetime_end) {
uint64_t invariantSize = ~0ULL;
if (ConstantInt *CI = dyn_cast<ConstantInt>(II->getOperand(1)))
invariantSize = CI->getZExtValue();
@@ -369,20 +369,41 @@
// calls to free() erase the entire structure, not just a field.
MemSize = ~0UL;
} else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
- CallSite QueryCS = CallSite::get(QueryInst);
- bool isReadOnly = AA->onlyReadsMemory(QueryCS);
- LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos,
- QueryParent);
+ int IntrinsicID = 0; // Intrinsic IDs start at 1.
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(QueryInst))
+ IntrinsicID = II->getIntrinsicID();
+
+ switch (IntrinsicID) {
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ case Intrinsic::invariant_start:
+ MemPtr = QueryInst->getOperand(2);
+ MemSize = cast<ConstantInt>(QueryInst->getOperand(1))->getZExtValue();
+ break;
+ case Intrinsic::invariant_end:
+ MemPtr = QueryInst->getOperand(3);
+ MemSize = cast<ConstantInt>(QueryInst->getOperand(2))->getZExtValue();
+ break;
+ default:
+ CallSite QueryCS = CallSite::get(QueryInst);
+ bool isReadOnly = AA->onlyReadsMemory(QueryCS);
+ LocalCache = getCallSiteDependencyFrom(QueryCS, isReadOnly, ScanPos,
+ QueryParent);
+ }
} else {
// Non-memory instruction.
LocalCache = MemDepResult::getClobber(--BasicBlock::iterator(ScanPos));
}
// If we need to do a pointer scan, make it happen.
- if (MemPtr)
- LocalCache = getPointerDependencyFrom(MemPtr, MemSize,
- isa<LoadInst>(QueryInst),
- ScanPos, QueryParent);
+ if (MemPtr) {
+ bool isLoad = !QueryInst->mayWriteToMemory();
+ if (IntrinsicInst *II = dyn_cast<MemoryUseIntrinsic>(QueryInst)) {
+ isLoad |= II->getIntrinsicID() == Intrinsic::lifetime_end;
+ }
+ LocalCache = getPointerDependencyFrom(MemPtr, MemSize, isLoad, ScanPos,
+ QueryParent);
+ }
// Remember the result!
if (Instruction *I = LocalCache.getInst())
Modified: llvm/trunk/test/Transforms/DeadStoreElimination/lifetime.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/DeadStoreElimination/lifetime.ll?rev=90045&r1=90044&r2=90045&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/DeadStoreElimination/lifetime.ll (original)
+++ llvm/trunk/test/Transforms/DeadStoreElimination/lifetime.ll Sat Nov 28 15:27:49 2009
@@ -1,6 +1,9 @@
; RUN: opt -S -dse < %s | FileCheck %s
-declare void @llvm.lifetime.end(i64, i8*)
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind
declare void @llvm.memset.i8(i8*, i8, i8, i32)
define void @test1() {
@@ -17,3 +20,18 @@
ret void
; CHECK: ret void
}
+
+define void @test2(i32* %P) {
+; CHECK: test2
+ %Q = getelementptr i32* %P, i32 1
+ %R = bitcast i32* %Q to i8*
+ call void @llvm.lifetime.start(i64 4, i8* %R)
+; CHECK: lifetime.start
+ store i32 0, i32* %Q ;; This store is dead.
+; CHECK-NOT: store
+ call void @llvm.lifetime.end(i64 4, i8* %R)
+; CHECK: lifetime.end
+ ret void
+}
+
+
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