Re: [llvm-commits] [llvm] r47247 - /llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp

[Owen Anderson]

I can't reproduce on my Mac Pro. Can you file a bug report with a reduce testcase?

--Owen

On Feb 18, 2008, at 1:43 PM, Evan Cheng wrote:

Hi Resistor,



Thanks,

Evan

On Feb 17, 2008, at 1:29 PM, Owen Anderson wrote:

This breaks MultiSource/Benchmarks/Prolangs-C++/city under x86-64. Please take a look.

Author: resistor
Date: Sun Feb 17 15:29:08 2008
New Revision: 47247

URL: http://llvm.org/viewvc/llvm-project?rev=47247&view=rev
Log:


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=47247&r1=47246&r2=47247&view=diff


--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)

@@ -21,7 +21,7 @@
#include "llvm/ParameterAttributes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
-#include "llvm/Intrinsics.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Pass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallVector.h"
@@ -228,6 +228,13 @@

   // callees could modify it.
   break; // next use
+    case Instruction::Call:

+      // not escape
+      if (isa<MemIntrinsic>(I))
+        return false;
+      else
+        return true;
 default:
   return true;
 }
@@ -247,8 +254,11 @@
 // Allocations and byval arguments are "new" objects.
 if (Object &&
     (isa<AllocationInst>(Object) ||

+         (isa<Argument>(Object) &&

+      // for noalias parameters) object.  If we can prove that

   // because it simply can't get its address.
   if (!AddressMightEscape(Object))


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Teach getModRefInfo that memcpy, memmove, and memset don't "capture" memory addresses. Also, noalias arguments are be considered "like" stack allocated ones for this purpose, because the only way they can be modref'ed is if they escape somewhere in the current function. = = = = = = = = = ===================================================================== +++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Sun Feb 17 15:29:08 2008 // If returned, the address will escape to calling functions, but no + // If the call is to a few known safe intrinsics, we know that it does - (isa<Argument>(Object) && cast<Argument>(Object)- >hasByValAttr()))) { - // Okay, the pointer is to a stack allocated object. If we can prove that + (cast<Argument>(Object)- >hasByValAttr() || + cast<Argument>(Object)- >hasNoAliasAttr())))) { + // Okay, the pointer is to a stack allocated (or effectively so, for // the pointer never "escapes", then we know the call cannot clobber it,

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