diff options
| author | Chris Lattner <sabre@nondot.org> | 2010-05-05 18:40:33 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-05-05 18:40:33 +0000 |
| commit | 8c5857980ab6b2432df890004f2f961bf5df47f6 (patch) | |
| tree | 70531bed5f06f4095393026899181c4b34bdcdb5 /lib/Support | |
| parent | b71c8d9f0b2e0c3b5cc204a460b599ee97981362 (diff) | |
| download | external_llvm-8c5857980ab6b2432df890004f2f961bf5df47f6.zip external_llvm-8c5857980ab6b2432df890004f2f961bf5df47f6.tar.gz external_llvm-8c5857980ab6b2432df890004f2f961bf5df47f6.tar.bz2 | |
Implement rdar://7415680 - Twine integer support lacks greatness
Microoptimize Twine's with unsigned and int to not pin their value to
the stack. This saves stack space in common cases and allows mem2reg
in the caller. A simple example is:
void foo(const Twine &);
void bar(int x) {
foo("xyz: " + Twine(x));
}
Before:
__Z3bari:
subq $40, %rsp
movl %edi, 36(%rsp)
leaq L_.str3(%rip), %rax
leaq 36(%rsp), %rcx
leaq 8(%rsp), %rdi
movq %rax, 8(%rsp)
movq %rcx, 16(%rsp)
movb $3, 24(%rsp)
movb $7, 25(%rsp)
callq __Z3fooRKN4llvm5TwineE
addq $40, %rsp
ret
After:
__Z3bari:
subq $24, %rsp
leaq L_.str3(%rip), %rax
movq %rax, (%rsp)
movslq %edi, %rax
movq %rax, 8(%rsp)
movb $3, 16(%rsp)
movb $7, 17(%rsp)
leaq (%rsp), %rdi
callq __Z3fooRKN4llvm5TwineE
addq $24, %rsp
ret
It saves 16 bytes of stack and one instruction in this case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103107 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Support')
| -rw-r--r-- | lib/Support/Twine.cpp | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/lib/Support/Twine.cpp b/lib/Support/Twine.cpp index 21504e9..b3ea013 100644 --- a/lib/Support/Twine.cpp +++ b/lib/Support/Twine.cpp @@ -48,10 +48,10 @@ void Twine::printOneChild(raw_ostream &OS, const void *Ptr, OS << *static_cast<const StringRef*>(Ptr); break; case Twine::DecUIKind: - OS << *static_cast<const unsigned int*>(Ptr); + OS << (unsigned)(uintptr_t)Ptr; break; case Twine::DecIKind: - OS << *static_cast<const int*>(Ptr); + OS << (int)(intptr_t)Ptr; break; case Twine::DecULKind: OS << *static_cast<const unsigned long*>(Ptr); @@ -95,10 +95,10 @@ void Twine::printOneChildRepr(raw_ostream &OS, const void *Ptr, << static_cast<const StringRef*>(Ptr) << "\""; break; case Twine::DecUIKind: - OS << "decUI:\"" << *static_cast<const unsigned int*>(Ptr) << "\""; + OS << "decUI:\"" << (unsigned)(uintptr_t)Ptr << "\""; break; case Twine::DecIKind: - OS << "decI:\"" << *static_cast<const int*>(Ptr) << "\""; + OS << "decI:\"" << (int)(intptr_t)Ptr << "\""; break; case Twine::DecULKind: OS << "decUL:\"" << *static_cast<const unsigned long*>(Ptr) << "\""; |