Teach BasicAA about noalias function parameters. Passes all of DejaGNU and test-suite.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40624 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 580f7e5..ffe7411 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -18,6 +18,7 @@
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
+#include "llvm/ParameterAttributes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
@@ -294,6 +295,21 @@
// Pointing at a discernible object?
if (O1) {
+ // Check for noalias attribute
+ if (isa<Argument>(O1)) {
+ const Argument *Arg = cast<Argument>(O1);
+ const Function *Func = Arg->getParent();
+ const ParamAttrsList *Attr = Func->getFunctionType()->getParamAttrs();
+ if (Attr) {
+ unsigned Idx = 1;
+ for (Function::const_arg_iterator I = Func->arg_begin(),
+ E = Func->arg_end(); I != E; ++I, ++Idx) {
+ if (&(*I) == Arg &&
+ Attr->paramHasAttr(Idx, ParamAttr::NoAlias))
+ return NoAlias;
+ }
+ }
+ }
if (O2) {
if (isa<Argument>(O1)) {
// Incoming argument cannot alias locally allocated object!
@@ -307,7 +323,22 @@
// If they are two different objects, we know that we have no alias...
return NoAlias;
}
-
+
+ // Check for noalias atrribute independently from above logic
+ if (isa<Argument>(O2)) {
+ const Argument *Arg = cast<Argument>(O2);
+ const Function *Func = Arg->getParent();
+ const ParamAttrsList *Attr = Func->getFunctionType()->getParamAttrs();
+ if (Attr) {
+ unsigned Idx = 1;
+ for (Function::const_arg_iterator I = Func->arg_begin(),
+ E = Func->arg_end(); I != E; ++I, ++Idx) {
+ if (&(*I) == Arg &&
+ Attr->paramHasAttr(Idx, ParamAttr::NoAlias))
+ return NoAlias;
+ }
+ }
+ }
// If they are the same object, they we can look at the indexes. If they
// index off of the object is the same for both pointers, they must alias.
// If they are provably different, they must not alias. Otherwise, we
diff --git a/test/Analysis/BasicAA/2007-07-31-NoAliasTest.ll b/test/Analysis/BasicAA/2007-07-31-NoAliasTest.ll
new file mode 100644
index 0000000..f760de3
--- /dev/null
+++ b/test/Analysis/BasicAA/2007-07-31-NoAliasTest.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep '1 may alias'
+; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep '5 no alias'
+; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep 'MayAlias: i32* %ptr4, i32* %ptr2'
+
+define void @_Z3fooPiS_RiS_(i32* noalias %ptr1, i32* %ptr2, i32* noalias %ptr3, i32* %ptr4) {
+entry:
+ store i32 0, i32* %ptr1
+ store i32 0, i32* %ptr2
+ store i32 0, i32* %ptr3
+ store i32 0, i32* %ptr4
+ ret void
+}
\ No newline at end of file