Author: lattner
Date: Sat Jan 12 12:54:29 2008
New Revision: 45912
URL: http://llvm.org/viewvc/llvm-project?rev=45912&view=rev
Log:
we don't have to make an explicit copy of a byval argument when
inlining a function if we know that the function does not write
to *any* memory. This implements test/Transforms/Inline/byval2.ll
Added:
llvm/trunk/test/Transforms/Inline/byval2.ll
Modified:
llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=45912&r1=45911&r2=45912&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Sat Jan 12 12:54:29 2008
@@ -241,10 +241,12 @@
Value *ActualArg = *AI;
// When byval arguments actually inlined, we need to make the copy
implied
- // by them actually explicit.
- // TODO: If we know that the callee never modifies the struct, we can
- // remove this copy.
- if (CalledFunc->paramHasAttr(ArgNo+1, ParamAttr::ByVal)) {
+ // 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->paramHasAttr(0, ParamAttr::ReadOnly) &&
+ !CalledFunc->paramHasAttr(0, ParamAttr::ReadNone)) {
const Type *AggTy = cast<PointerType>(I->getType())->getElementType();
const Type *VoidPtrTy = PointerType::getUnqual(Type::Int8Ty);
Added: llvm/trunk/test/Transforms/Inline/byval2.ll
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/byval2.ll?rev=45912&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Inline/byval2.ll (added)
+++ llvm/trunk/test/Transforms/Inline/byval2.ll Sat Jan 12 12:54:29 2008
@@ -0,0 +1,28 @@
+; RUN: llvm-as < %s | opt -inline | llvm-dis | not grep {llvm.memcpy}
+
+; Inlining a byval struct should NOT cause an explicit copy
+; into an alloca if the function is readonly
+
+ %struct.ss = type { i32, i64 }
[EMAIL PROTECTED] = internal constant [10 x i8] c"%d, %lld\0A\00"
; <[10 x i8]*> [#uses=1]
+
+define internal i32 @f(%struct.ss* byval %b) nounwind readonly {
+entry:
+ %tmp = getelementptr %struct.ss* %b, i32 0, i32 0 ;
<i32*> [#uses=2]
+ %tmp1 = load i32* %tmp, align 4 ; <i32> [#uses=1]
+ %tmp2 = add i32 %tmp1, 1 ; <i32> [#uses=1]
+ ret i32 %tmp2
+}
+
+declare i32 @printf(i8*, ...) nounwind
+
+define i32 @main() nounwind {
+entry:
+ %S = alloca %struct.ss ; <%struct.ss*> [#uses=4]
+ %tmp1 = getelementptr %struct.ss* %S, i32 0, i32 0 ;
<i32*> [#uses=1]
+ store i32 1, i32* %tmp1, align 8
+ %tmp4 = getelementptr %struct.ss* %S, i32 0, i32 1 ;
<i64*> [#uses=1]
+ store i64 2, i64* %tmp4, align 4
+ %X = call i32 @f( %struct.ss* byval %S ) nounwind
+ ret i32 %X
+}
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