Author: baldrick
Date: Sun Jan 27 12:12:58 2008
New Revision: 46416
URL: http://llvm.org/viewvc/llvm-project?rev=46416&view=rev
Log:
Revert r46393: readonly/readnone functions are no
longer allowed to write through byval arguments.
Modified:
llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
llvm/trunk/test/Transforms/Inline/byval2.ll
Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=46416&r1=46415&r2=46416&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Sun Jan 27 12:12:58 2008
@@ -240,15 +240,12 @@
E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
Value *ActualArg = *AI;
- // When byval arguments are inlined, we need to make the copy implied
- // by them explicit. It is tempting to think that this is not needed if
- // the callee is readonly, because the callee doesn't modify the struct.
- // However this would be wrong: readonly means that any writes the callee
- // performs are not visible to the caller. But writes by the callee to
- // an argument passed byval are by definition not visible to the caller!
- // Since we allow this kind of readonly function, there needs to be an
- // explicit copy in order to keep the writes invisible after inlining.
- if (CalledFunc->paramHasAttr(ArgNo+1, ParamAttr::ByVal)) {
+ // When byval arguments actually inlined, we need to make the copy
implied
+ // by them explicit. However, we don't do this if the callee is readonly
+ // or readnone, because the copy would be unneeded: the callee doesn't
+ // modify the struct.
+ if (CalledFunc->paramHasAttr(ArgNo+1, ParamAttr::ByVal) &&
+ !CalledFunc->onlyReadsMemory()) {
const Type *AggTy = cast<PointerType>(I->getType())->getElementType();
const Type *VoidPtrTy = PointerType::getUnqual(Type::Int8Ty);
Modified: llvm/trunk/test/Transforms/Inline/byval2.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/byval2.ll?rev=46416&r1=46415&r2=46416&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/Inline/byval2.ll (original)
+++ llvm/trunk/test/Transforms/Inline/byval2.ll Sun Jan 27 12:12:58 2008
@@ -1,7 +1,7 @@
-; RUN: llvm-as < %s | opt -inline | llvm-dis | grep {llvm.memcpy}
+; RUN: llvm-as < %s | opt -inline | llvm-dis | not grep {llvm.memcpy}
-; Inlining a byval struct should cause an explicit copy
-; into an alloca even if the function is readonly
+; Inlining a byval struct should NOT cause an explicit copy
+; into an alloca if the function is readonly
%struct.ss = type { i32, i64 }
@.str = internal constant [10 x i8] c"%d, %lld\0A\00" ; <[10 x i8]*>
[#uses=1]
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