[llvm-commits] [llvm] r107777 - /llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
Dan Gohman
gohman at apple.com
Wed Jul 7 07:30:04 PDT 2010
Author: djg
Date: Wed Jul 7 09:30:04 2010
New Revision: 107777
URL: http://llvm.org/viewvc/llvm-project?rev=107777&view=rev
Log:
Minore code simplification.
Modified:
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=107777&r1=107776&r2=107777&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Wed Jul 7 09:30:04 2010
@@ -763,8 +763,22 @@
if ((isa<ConstantPointerNull>(O2) && isKnownNonNull(O1)) ||
(isa<ConstantPointerNull>(O1) && isKnownNonNull(O2)))
return NoAlias;
- }
+ // If one pointer is the result of a call/invoke or load and the other is a
+ // non-escaping local object within the same function, then we know the
+ // object couldn't escape to a point where the call could return it.
+ //
+ // Note that if the pointers are in different functions, there are a
+ // variety of complications. A call with a nocapture argument may still
+ // temporary store the nocapture argument's value in a temporary memory
+ // location if that memory location doesn't escape. Or it may pass a
+ // nocapture value to other functions as long as they don't capture it.
+ if (isEscapeSource(O1) && isNonEscapingLocalObject(O2))
+ return NoAlias;
+ if (isEscapeSource(O2) && isNonEscapingLocalObject(O1))
+ return NoAlias;
+ }
+
// If the size of one access is larger than the entire object on the other
// side, then we know such behavior is undefined and can assume no alias.
if (TD)
@@ -772,22 +786,6 @@
(V2Size != ~0U && isObjectSmallerThan(O1, V2Size, *TD)))
return NoAlias;
- // If one pointer is the result of a call/invoke or load and the other is a
- // non-escaping local object within the same function, then we know the
- // object couldn't escape to a point where the call could return it.
- //
- // Note that if the pointers are in different functions, there are a
- // variety of complications. A call with a nocapture argument may still
- // temporary store the nocapture argument's value in a temporary memory
- // location if that memory location doesn't escape. Or it may pass a
- // nocapture value to other functions as long as they don't capture it.
- if (O1 != O2) {
- if (isEscapeSource(O1) && isNonEscapingLocalObject(O2))
- return NoAlias;
- if (isEscapeSource(O2) && isNonEscapingLocalObject(O1))
- return NoAlias;
- }
-
// FIXME: This isn't aggressively handling alias(GEP, PHI) for example: if the
// GEP can't simplify, we don't even look at the PHI cases.
if (!isa<GEPOperator>(V1) && isa<GEPOperator>(V2)) {
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