instcombine: Migrate stpcpy optimizations

This patch migrates the stpcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.  Note that the
__stpcpy_chk simplifications were migrated in a previous commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167083 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Meador Inge 2012-10-31 00:20:56 +00:00
parent fa9d1372c9
commit e6d781fd3c
6 changed files with 111 additions and 99 deletions

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@ -134,52 +134,6 @@ static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
//===----------------------------------------------------------------------===//
namespace {
//===---------------------------------------===//
// 'stpcpy' Optimizations
struct StpCpyOpt: public LibCallOptimization {
bool OptChkCall; // True if it's optimizing a __stpcpy_chk libcall.
StpCpyOpt(bool c) : OptChkCall(c) {}
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "stpcpy" function prototype.
unsigned NumParams = OptChkCall ? 3 : 2;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != NumParams ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
// These optimizations require DataLayout.
if (!TD) return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, TD, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0;
}
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(TD->getIntPtrType(PT),
Len - 1));
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
if (!OptChkCall || !EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B,
TD, TLI))
B.CreateMemCpy(Dst, Src, LenV, 1);
return DstEnd;
}
};
//===---------------------------------------===//
// 'strncpy' Optimizations
@ -1242,7 +1196,6 @@ namespace {
StringMap<LibCallOptimization*> Optimizations;
// String and Memory LibCall Optimizations
StpCpyOpt StpCpy; StpCpyOpt StpCpyChk;
StrNCpyOpt StrNCpy;
StrLenOpt StrLen; StrPBrkOpt StrPBrk;
StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
@ -1261,8 +1214,8 @@ namespace {
bool Modified; // This is only used by doInitialization.
public:
static char ID; // Pass identification
SimplifyLibCalls() : FunctionPass(ID), StpCpy(false), StpCpyChk(true),
UnaryDoubleFP(false), UnsafeUnaryDoubleFP(true) {
SimplifyLibCalls() : FunctionPass(ID), UnaryDoubleFP(false),
UnsafeUnaryDoubleFP(true) {
initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
}
void AddOpt(LibFunc::Func F, LibCallOptimization* Opt);
@ -1314,7 +1267,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
void SimplifyLibCalls::InitOptimizations() {
// String and Memory LibCall Optimizations
Optimizations["strncpy"] = &StrNCpy;
Optimizations["stpcpy"] = &StpCpy;
Optimizations["strlen"] = &StrLen;
Optimizations["strpbrk"] = &StrPBrk;
Optimizations["strtol"] = &StrTo;
@ -1332,9 +1284,6 @@ void SimplifyLibCalls::InitOptimizations() {
Optimizations["memmove"] = &MemMove;
AddOpt(LibFunc::memset, &MemSet);
// _chk variants of String and Memory LibCall Optimizations.
Optimizations["__stpcpy_chk"] = &StpCpyChk;
// Math Library Optimizations
Optimizations["cosf"] = &Cos;
Optimizations["cos"] = &Cos;

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@ -592,6 +592,42 @@ struct StrCpyOpt : public LibCallOptimization {
}
};
struct StpCpyOpt: public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "stpcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
// These optimizations require DataLayout.
if (!TD) return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, TD, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0;
}
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(TD->getIntPtrType(PT),
Len - 1));
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
B.CreateMemCpy(Dst, Src, LenV, 1);
return DstEnd;
}
};
} // End anonymous namespace.
namespace llvm {
@ -617,6 +653,7 @@ class LibCallSimplifierImpl {
StrCmpOpt StrCmp;
StrNCmpOpt StrNCmp;
StrCpyOpt StrCpy;
StpCpyOpt StpCpy;
void initOptimizations();
public:
@ -646,6 +683,7 @@ void LibCallSimplifierImpl::initOptimizations() {
Optimizations["strcmp"] = &StrCmp;
Optimizations["strncmp"] = &StrNCmp;
Optimizations["strcpy"] = &StrCpy;
Optimizations["stpcpy"] = &StpCpy;
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {

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@ -0,0 +1,46 @@
; Test that the stpcpy library call simplifier works correctly.
; RUN: opt < %s -instcombine -S | FileCheck %s
;
; This transformation requires the pointer size, as it assumes that size_t is
; the size of a pointer.
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
@hello = constant [6 x i8] c"hello\00"
@a = common global [32 x i8] zeroinitializer, align 1
@b = common global [32 x i8] zeroinitializer, align 1
declare i8* @stpcpy(i8*, i8*)
define i8* @test_simplify1() {
; CHECK: @test_simplify1
%dst = getelementptr [32 x i8]* @a, i32 0, i32 0
%src = getelementptr [6 x i8]* @hello, i32 0, i32 0
%ret = call i8* @stpcpy(i8* %dst, i8* %src)
; CHECK: @llvm.memcpy.p0i8.p0i8.i32
; CHECK-NEXT: getelementptr inbounds ([32 x i8]* @a, i32 0, i32 5)
ret i8* %ret
}
define i8* @test_simplify2() {
; CHECK: @test_simplify2
%dst = getelementptr [32 x i8]* @a, i32 0, i32 0
%ret = call i8* @stpcpy(i8* %dst, i8* %dst)
; CHECK: [[LEN:%[a-z]+]] = call i32 @strlen
; CHECK-NEXT: getelementptr inbounds [32 x i8]* @a, i32 0, i32 [[LEN]]
ret i8* %ret
}
define i8* @test_no_simplify1() {
; CHECK: @test_no_simplify1
%dst = getelementptr [32 x i8]* @a, i32 0, i32 0
%src = getelementptr [32 x i8]* @b, i32 0, i32 0
%ret = call i8* @stpcpy(i8* %dst, i8* %src)
; CHECK: call i8* @stpcpy
ret i8* %ret
}

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@ -0,0 +1,22 @@
; Test that the stpcpy library call simplifier works correctly.
; RUN: opt < %s -instcombine -S | FileCheck %s
;
; This transformation requires the pointer size, as it assumes that size_t is
; the size of a pointer.
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
@hello = constant [6 x i8] c"hello\00"
@a = common global [32 x i8] zeroinitializer, align 1
declare i16* @stpcpy(i8*, i8*)
define void @test_no_simplify1() {
; CHECK: @test_no_simplify1
%dst = getelementptr [32 x i8]* @a, i32 0, i32 0
%src = getelementptr [6 x i8]* @hello, i32 0, i32 0
call i16* @stpcpy(i8* %dst, i8* %src)
; CHECK: call i16* @stpcpy
ret void
}

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@ -16,7 +16,7 @@ define void @test_simplify1() {
%dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
%src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
; CHECK-NEXT: call i8* @stpcpy
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 60)
ret void
}
@ -26,7 +26,7 @@ define void @test_simplify2() {
%dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
%src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
; CHECK-NEXT: call i8* @stpcpy
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 12)
ret void
}
@ -36,7 +36,7 @@ define void @test_simplify3() {
%dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0
%src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0
; CHECK-NEXT: call i8* @stpcpy
; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32
call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 -1)
ret void
}

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@ -1,43 +0,0 @@
; Test that the StpCpyOptimizer works correctly
; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
; This transformation requires the pointer size, as it assumes that size_t is
; the size of a pointer.
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
@hello = constant [6 x i8] c"hello\00"
declare i8* @stpcpy(i8*, i8*)
declare i8* @__stpcpy_chk(i8*, i8*, i32) nounwind
declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly
define i32 @t1() {
; CHECK: @t1
%target = alloca [1024 x i8]
%arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
%arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
%rslt1 = call i8* @stpcpy( i8* %arg1, i8* %arg2 )
; CHECK: @llvm.memcpy.p0i8.p0i8.i32
ret i32 0
}
define i32 @t2() {
; CHECK: @t2
%target = alloca [1024 x i8]
%arg1 = getelementptr [1024 x i8]* %target, i32 0, i32 0
%arg2 = getelementptr [6 x i8]* @hello, i32 0, i32 0
%tmp1 = call i32 @llvm.objectsize.i32(i8* %arg1, i1 false)
%rslt1 = call i8* @__stpcpy_chk(i8* %arg1, i8* %arg2, i32 %tmp1)
; CHECK: @__memcpy_chk
ret i32 0
}
define i8* @t3(i8* %arg) {
; CHECK: @t3
%stpcpy = tail call i8* @stpcpy(i8* %arg, i8* %arg)
; CHECK: [[LEN:%[a-z]+]] = call i32 @strlen(i8* %arg)
; CHECK-NEXT: getelementptr inbounds i8* %arg, i32 [[LEN]]
ret i8* %stpcpy
}