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Add constant folding for strspn and strcspn to SimplifyLibCalls.

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llvm-svn: 115116
This commit is contained in:
Benjamin Kramer 2010-09-30 00:58:35 +00:00
parent 0c653599a9
commit 2a44a539e2
3 changed files with 105 additions and 15 deletions
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6
lib/Target/README.txt
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@ -1340,12 +1340,6 @@ void foo (int a, struct T b)
simplifylibcalls should do several optimizations for strspn/strcspn:
strcspn(x, "") -> strlen(x)
strcspn("", x) -> 0
strspn("", x) -> 0
strspn(x, "") -> strlen(x)
strspn(x, "a") -> strchr(x, 'a')-x
strcspn(x, "a") -> inlined loop for up to 3 letters (similarly for strspn):
size_t __strcspn_c3 (__const char *__s, int __reject1, int __reject2,

73
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@ -583,6 +583,67 @@ struct StrToOpt : public LibCallOptimization {
}
};
//===---------------------------------------===//
// 'strspn' Optimizations
struct StrSpnOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
const FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return 0;
std::string S1, S2;
bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
// strspn(s, "") -> 0
// strspn("", s) -> 0
if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
return Constant::getNullValue(CI->getType());
// Constant folding.
if (HasS1 && HasS2)
return ConstantInt::get(CI->getType(), strspn(S1.c_str(), S2.c_str()));
return 0;
}
};
//===---------------------------------------===//
// 'strcspn' Optimizations
struct StrCSpnOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
const FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return 0;
std::string S1, S2;
bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
// strcspn("", s) -> 0
if (HasS1 && S1.empty())
return Constant::getNullValue(CI->getType());
// Constant folding.
if (HasS1 && HasS2)
return ConstantInt::get(CI->getType(), strcspn(S1.c_str(), S2.c_str()));
// strcspn(s, "") -> strlen(s)
if (TD && HasS2 && S2.empty())
return EmitStrLen(CI->getArgOperand(0), B, TD);
return 0;
}
};
//===---------------------------------------===//
// 'strstr' Optimizations
@ -1297,7 +1358,7 @@ namespace {
StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrRChrOpt StrRChr;
StrCmpOpt StrCmp; StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
StrNCpyOpt StrNCpy; StrLenOpt StrLen; StrPBrkOpt StrPBrk;
StrToOpt StrTo; StrStrOpt StrStr;
StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
// Math Library Optimizations
PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
@ -1357,6 +1418,8 @@ void SimplifyLibCalls::InitOptimizations() {
Optimizations["strtoll"] = &StrTo;
Optimizations["strtold"] = &StrTo;
Optimizations["strtoull"] = &StrTo;
Optimizations["strspn"] = &StrSpn;
Optimizations["strcspn"] = &StrCSpn;
Optimizations["strstr"] = &StrStr;
Optimizations["memcmp"] = &MemCmp;
Optimizations["memcpy"] = &MemCpy;
@ -2250,14 +2313,6 @@ bool SimplifyLibCalls::doInitialization(Module &M) {
// * stpcpy(str, "literal") ->
// llvm.memcpy(str,"literal",strlen("literal")+1,1)
//
// strspn, strcspn:
// * strspn(s,a) -> const_int (if both args are constant)
// * strspn("",a) -> 0
// * strspn(s,"") -> 0
// * strcspn(s,a) -> const_int (if both args are constant)
// * strcspn("",a) -> 0
// * strcspn(s,"") -> strlen(a)
//
// tan, tanf, tanl:
// * tan(atan(x)) -> x
//

41
test/Transforms/SimplifyLibCalls/StrSpn.ll Normal file
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@ -0,0 +1,41 @@
; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
target datalayout = "-p:64:64:64"
@abcba = constant [6 x i8] c"abcba\00"
@abc = constant [4 x i8] c"abc\00"
@null = constant [1 x i8] zeroinitializer
declare i64 @strspn(i8*, i8*)
define i64 @testspn(i8* %s1, i8* %s2) {
%abcba_p = getelementptr [6 x i8]* @abcba, i32 0, i32 0
%abc_p = getelementptr [4 x i8]* @abc, i32 0, i32 0
%null_p = getelementptr [1 x i8]* @null, i32 0, i32 0
%test1 = call i64 @strspn(i8* %s1, i8* %null_p)
%test2 = call i64 @strspn(i8* %null_p, i8* %s2)
%test3 = call i64 @strspn(i8* %abcba_p, i8* %abc_p)
; CHECK-NOT: call i64 @strspn
%test4 = call i64 @strspn(i8* %s1, i8* %s2)
; CHECK: call i64 @strspn(i8* %s1, i8* %s2)
ret i64 %test3
; CHECK ret i64 5
}
declare i64 @strcspn(i8*, i8*)
define i64 @testcspn(i8* %s1, i8* %s2) {
%abcba_p = getelementptr [6 x i8]* @abcba, i32 0, i32 0
%abc_p = getelementptr [4 x i8]* @abc, i32 0, i32 0
%null_p = getelementptr [1 x i8]* @null, i32 0, i32 0
%test1 = call i64 @strcspn(i8* %s1, i8* %null_p)
; CHECK: call i64 @strlen(i8* %s1)
%test2 = call i64 @strcspn(i8* %null_p, i8* %s2)
%test3 = call i64 @strcspn(i8* %abcba_p, i8* %abc_p)
; CHECK-NOT: call i64 @strcspn
%test4 = call i64 @strcspn(i8* %s1, i8* %s2)
; CHECK: call i64 @strcspn(i8* %s1, i8* %s2)
%add0 = add i64 %test1, %test3
; CHECK: add i64 %{{.+}}, 0
ret i64 %add0
}