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https://github.com/c64scene-ar/llvm-6502.git
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LLVM backend for 6502
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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llvm.spec.in | ||
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Makefile.common | ||
Makefile.config.in | ||
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ModuleInfo.txt | ||
README.txt |
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