[llvm] r193356 - Inliner: Handle readonly attribute per argument when adding memcpy
Tom Stellard
thomas.stellard at amd.com
Thu Oct 24 09:38:33 PDT 2013
Author: tstellar
Date: Thu Oct 24 11:38:33 2013
New Revision: 193356
URL: http://llvm.org/viewvc/llvm-project?rev=193356&view=rev
Log:
Inliner: Handle readonly attribute per argument when adding memcpy
Patch by: Vincent Lejeune
Modified:
llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
llvm/trunk/test/Transforms/Inline/byval.ll
Modified: llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp?rev=193356&r1=193355&r2=193356&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/InlineFunction.cpp Thu Oct 24 11:38:33 2013
@@ -337,33 +337,35 @@ static void UpdateCallGraphAfterInlining
/// HandleByValArgument - When inlining a call site that has a byval argument,
/// we have to make the implicit memcpy explicit by adding it.
-static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
+static Value *HandleByValArgument(Value *PassedValue,
+ const Argument *ArgumentSignature,
+ Instruction *TheCall,
const Function *CalledFunc,
InlineFunctionInfo &IFI,
unsigned ByValAlignment) {
- Type *AggTy = cast<PointerType>(Arg->getType())->getElementType();
+ Type *AggTy = cast<PointerType>(PassedValue->getType())->getElementType();
// If the called function is readonly, then it could not mutate the caller's
// copy of the byval'd memory. In this case, it is safe to elide the copy and
// temporary.
- if (CalledFunc->onlyReadsMemory()) {
+ if (CalledFunc->onlyReadsMemory() || ArgumentSignature->onlyReadsMemory()) {
// If the byval argument has a specified alignment that is greater than the
// passed in pointer, then we either have to round up the input pointer or
// give up on this transformation.
if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
- return Arg;
+ return PassedValue;
// If the pointer is already known to be sufficiently aligned, or if we can
// round it up to a larger alignment, then we don't need a temporary.
- if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
+ if (getOrEnforceKnownAlignment(PassedValue, ByValAlignment,
IFI.TD) >= ByValAlignment)
- return Arg;
+ return PassedValue;
// Otherwise, we have to make a memcpy to get a safe alignment. This is bad
// for code quality, but rarely happens and is required for correctness.
}
- LLVMContext &Context = Arg->getContext();
+ LLVMContext &Context = PassedValue->getContext();
Type *VoidPtrTy = Type::getInt8PtrTy(Context);
@@ -379,7 +381,7 @@ static Value *HandleByValArgument(Value
Function *Caller = TheCall->getParent()->getParent();
- Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(),
+ Value *NewAlloca = new AllocaInst(AggTy, 0, Align, PassedValue->getName(),
&*Caller->begin()->begin());
// Emit a memcpy.
Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
@@ -387,7 +389,7 @@ static Value *HandleByValArgument(Value
Intrinsic::memcpy,
Tys);
Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
- Value *SrcCast = new BitCastInst(Arg, VoidPtrTy, "tmp", TheCall);
+ Value *SrcCast = new BitCastInst(PassedValue, VoidPtrTy, "tmp", TheCall);
Value *Size;
if (IFI.TD == 0)
@@ -588,13 +590,14 @@ bool llvm::InlineFunction(CallSite CS, I
for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
E = CalledFunc->arg_end(); I != E; ++I, ++AI, ++ArgNo) {
Value *ActualArg = *AI;
+ const Argument *Arg = I;
// 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 (CS.isByValArgument(ArgNo)) {
- ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
+ ActualArg = HandleByValArgument(ActualArg, Arg, TheCall, CalledFunc, IFI,
CalledFunc->getParamAlignment(ArgNo+1));
// Calls that we inline may use the new alloca, so we need to clear
Modified: llvm/trunk/test/Transforms/Inline/byval.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/byval.ll?rev=193356&r1=193355&r2=193356&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/Inline/byval.ll (original)
+++ llvm/trunk/test/Transforms/Inline/byval.ll Thu Oct 24 11:38:33 2013
@@ -25,7 +25,7 @@ entry:
store i64 2, i64* %tmp4, align 4
call void @f( %struct.ss* byval %S ) nounwind
ret i32 0
-; CHECK: @test1()
+; CHECK-LABEL: @test1()
; CHECK: %S1 = alloca %struct.ss
; CHECK: %S = alloca %struct.ss
; CHECK: call void @llvm.memcpy
@@ -52,7 +52,7 @@ entry:
store i64 2, i64* %tmp4, align 4
%X = call i32 @f2( %struct.ss* byval %S ) nounwind
ret i32 %X
-; CHECK: @test2()
+; CHECK-LABEL: @test2()
; CHECK: %S = alloca %struct.ss
; CHECK-NOT: call void @llvm.memcpy
; CHECK: ret i32
@@ -74,7 +74,7 @@ entry:
%S = alloca %struct.ss, align 1 ;; May not be aligned.
call void @f3( %struct.ss* byval align 64 %S) nounwind
ret void
-; CHECK: @test3()
+; CHECK-LABEL: @test3()
; CHECK: %S1 = alloca %struct.ss, align 64
; CHECK: %S = alloca %struct.ss
; CHECK: call void @llvm.memcpy
@@ -97,10 +97,35 @@ entry:
%S = alloca %struct.ss, align 2 ; <%struct.ss*> [#uses=4]
%X = call i32 @f4( %struct.ss* byval align 64 %S ) nounwind
ret i32 %X
-; CHECK: @test4()
+; CHECK-LABEL: @test4()
; CHECK: %S = alloca %struct.ss, align 64
; CHECK-NOT: call void @llvm.memcpy
; CHECK: call void @g3
; CHECK: ret i32 4
}
+; Inlining a byval struct should NOT cause an explicit copy
+; into an alloca if the parameter is readonly
+
+define internal i32 @f5(%struct.ss* byval readonly %b) nounwind {
+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
+}
+
+define i32 @test5() 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 @f5( %struct.ss* byval %S ) nounwind
+ ret i32 %X
+; CHECK-LABEL: @test5()
+; CHECK: %S = alloca %struct.ss
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK: ret i32
+}
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