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Teach MemoryBuiltins and InstructionSimplify that operator new never returns NULL.

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This is safe per C++11 18.6.1.1p3: [operator new returns] a non-null pointer to
suitably aligned storage (3.7.4), or else throw a bad_alloc exception. This
requirement is binding on a replacement version of this function.

Brings us a tiny bit closer to eliminating more vector push_backs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191310 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer
2013-09-24 16:37:51 +00:00
parent d721520e4c
commit 6629210aaf
6 changed files with 46 additions and 7 deletions
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16
lib/Analysis/MemoryBuiltins.cpp
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@@ -35,6 +35,7 @@ enum AllocType {
CallocLike = 1<<1, // allocates + bzero
ReallocLike = 1<<2, // reallocates
StrDupLike = 1<<3,
OpNewLike = MallocLike | (1<<4), // allocates; never returns null
AllocLike = MallocLike | CallocLike | StrDupLike,
AnyAlloc = MallocLike | CallocLike | ReallocLike | StrDupLike
};
@@ -52,13 +53,13 @@ struct AllocFnsTy {
static const AllocFnsTy AllocationFnData[] = {
{LibFunc::malloc, MallocLike, 1, 0, -1},
{LibFunc::valloc, MallocLike, 1, 0, -1},
{LibFunc::Znwj, MallocLike, 1, 0, -1}, // new(unsigned int)
{LibFunc::Znwj, OpNewLike, 1, 0, -1}, // new(unsigned int)
{LibFunc::ZnwjRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned int, nothrow)
{LibFunc::Znwm, MallocLike, 1, 0, -1}, // new(unsigned long)
{LibFunc::Znwm, OpNewLike, 1, 0, -1}, // new(unsigned long)
{LibFunc::ZnwmRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new(unsigned long, nothrow)
{LibFunc::Znaj, MallocLike, 1, 0, -1}, // new[](unsigned int)
{LibFunc::Znaj, OpNewLike, 1, 0, -1}, // new[](unsigned int)
{LibFunc::ZnajRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned int, nothrow)
{LibFunc::Znam, MallocLike, 1, 0, -1}, // new[](unsigned long)
{LibFunc::Znam, OpNewLike, 1, 0, -1}, // new[](unsigned long)
{LibFunc::ZnamRKSt9nothrow_t, MallocLike, 2, 0, -1}, // new[](unsigned long, nothrow)
{LibFunc::posix_memalign, MallocLike, 3, 2, -1},
{LibFunc::calloc, CallocLike, 2, 0, 1},
@@ -189,6 +190,13 @@ bool llvm::isReallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
return getAllocationData(V, ReallocLike, TLI, LookThroughBitCast);
}
/// \brief Tests if a value is a call or invoke to a library function that
/// allocates memory and never returns null (such as operator new).
bool llvm::isOperatorNewLikeFn(const Value *V, const TargetLibraryInfo *TLI,
bool LookThroughBitCast) {
return getAllocationData(V, OpNewLike, TLI, LookThroughBitCast);
}
/// extractMallocCall - Returns the corresponding CallInst if the instruction
/// is a malloc call. Since CallInst::CreateMalloc() only creates calls, we
/// ignore InvokeInst here.