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| author | Nick Lewycky <nicholas@mxc.ca> | 2009-10-13 07:48:38 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2009-10-13 07:48:38 +0000 |
| commit | fc461aee7449bb8010b6f4946d88afd8e2b05e3e (patch) | |
| tree | 71cc8d429e4db5afd033db00609120b5f546001d | |
| parent | c888d3594875d75fc81e4cd3b6630b4b88f8054e (diff) | |
| download | external_llvm-fc461aee7449bb8010b6f4946d88afd8e2b05e3e.zip external_llvm-fc461aee7449bb8010b6f4946d88afd8e2b05e3e.tar.gz external_llvm-fc461aee7449bb8010b6f4946d88afd8e2b05e3e.tar.bz2 | |
Teach BasicAA a little something about the atomic intrinsics: they can only
modify through the pointer they're given.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83959 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/Analysis/BasicAliasAnalysis.cpp | 21 | ||||
| -rw-r--r-- | test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll | 16 |
2 files changed, 37 insertions, 0 deletions
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp index 5fa87ff..2e3c75d 100644 --- a/lib/Analysis/BasicAliasAnalysis.cpp +++ b/lib/Analysis/BasicAliasAnalysis.cpp @@ -284,6 +284,27 @@ BasicAliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) { if (!passedAsArg) return NoModRef; } + + if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CS.getInstruction())) { + switch (II->getIntrinsicID()) { + default: break; + case Intrinsic::atomic_cmp_swap: + case Intrinsic::atomic_swap: + case Intrinsic::atomic_load_add: + case Intrinsic::atomic_load_sub: + case Intrinsic::atomic_load_and: + case Intrinsic::atomic_load_nand: + case Intrinsic::atomic_load_or: + case Intrinsic::atomic_load_xor: + case Intrinsic::atomic_load_max: + case Intrinsic::atomic_load_min: + case Intrinsic::atomic_load_umax: + case Intrinsic::atomic_load_umin: + if (alias(II->getOperand(1), Size, P, Size) == NoAlias) + return NoModRef; + break; + } + } } // The AliasAnalysis base class has some smarts, lets use them. diff --git a/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll b/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll new file mode 100644 index 0000000..3ccbc2f --- /dev/null +++ b/test/Analysis/BasicAA/2009-10-13-AtomicModRef.ll @@ -0,0 +1,16 @@ +; RUN: opt -gvn -S < %s | FileCheck %s + +declare i8 @llvm.atomic.load.add.i8.p0i8(i8*, i8) + +define void @foo(i8* %ptr) { + %P = getelementptr i8* %ptr, i32 0 + %Q = getelementptr i8* %ptr, i32 1 +; CHECK: getelementptr + %X = load i8* %P +; CHECK: = load + %Y = call i8 @llvm.atomic.load.add.i8.p0i8(i8* %Q, i8 1) + %Z = load i8* %P +; CHECK-NOT: = load + ret void +; CHECK: ret void +} |