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ea03e10fac
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 |
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