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	Commit message (Collapse)	Author	Files	Lines
2018-10-20	adapt setlocale to support possibility of failure	Rich Felker	2	-12/+22
	introduce a new LOC_MAP_FAILED sentinel for errors, since null pointers for a category's locale map indicate the C locale. at this time, __get_locale does not fail, so there should be no functional change by this commit.
2018-10-18	adjust types in FILE struct to make line buffering check less expensive	Rich Felker	1	-4/+2
	the choice of signed char for lbf was a theoretically space-saving hack that was not helping, and was unwantedly expensive. while comparing bytes against a byte-sized member sounds easy, the trick here was that the byte to be compared was unsigned while the lbf member was signed, making it possible to set lbf negative to disable line buffering. however, this imposed a requirement to promote both operands, zero-extending one and sign-extending the other, in order to compare them. to fix this, repurpose the waiters count slot (unused since commit c21f750727515602a9e84f2a190ee8a0a2aeb2a1). while we're at it, switch mode (orientation) from signed char to int as well. this makes no semantic difference (its only possible values are -1, 0, and 1) but it might help on archs where byte access is awkward.
2018-10-18	optimize internal putc_unlocked macro used in putc	Rich Felker	1	-1/+2
	to check whether flush due to line buffering is needed, the int-type character argument must be truncated to unsigned char for comparison. if the original value is subsequently passed to __overflow, it must be preserved, adding to register pressure. since it doesn't matter, truncate all uses so the original value is no longer live.
2018-10-18	fix wrong result for putc variants due to operator precedence	Rich Felker	1	-1/+1
	the internal putc_unlocked macro was wrongly returning a meaningless boolean result rather than the written character or EOF. bug was found by reading (very surprising) asm.
2018-10-18	further optimize getc/putc when locking is needed	Rich Felker	2	-10/+10
	check whether the lock is free before loading the calling thread's tid. if so, just use a dummy tid value that cannot compare equal to any actual thread id (because it's one bit wider). this also avoids the need to save the tid and pass it to locking_getc or locking_putc, reducing register pressure. this change might slightly hurt the case where the caller already holds the lock, but it does not affect the single-threaded case, and may significantly improve the multi-threaded case, especially on archs where loading the thread pointer is disproportionately expensive like early mips and arm ISA levels. but even on i386 it helps, at least on some machines; I measured roughly a 10-15% improvement.
2018-10-18	use prototype for function pointer in static link libc init barrier	Rich Felker	1	-1/+1
	this is not needed for correctness, but doesn't hurt, and in some cases the compiler may pessimize the call assuming the callee might be variadic when it lacks a prototype.
2018-10-18	fix error in constraints for static link libc init barrier	Rich Felker	1	-1/+1
	commit 4390383b32250a941ec616e8bff6f568a801b1c0 inadvertently used "r" instead of "0" for the input constraint, which only happened to work for the configuration I tested it on because it usually makes sense for the compiler to choose the same input and output register.