Re: Suboptimal inline heuristics due to non-code sections

From: Linus Torvalds
Date: Tue May 01 2018 - 12:52:14 EST


On Tue, May 1, 2018 at 9:46 AM Nadav Amit <namit@xxxxxxxxxx> wrote:

> My bad. Itâs not the new-line. Let me do some more digging.

From the gcc docs:

Some targets require that GCC track the size of each instruction used
in order to generate correct code. Because the final length of the
code produced by an @code{asm} statement is only known by the
assembler, GCC must make an estimate as to how big it will be. It
does this by counting the number of instructions in the pattern of the
@code{asm} and multiplying that by the length of the longest
instruction supported by that processor. (When working out the number
of instructions, it assumes that any occurrence of a newline or of
whatever statement separator character is supported by the assembler --
typically @samp{;} --- indicates the end of an instruction.)

so it probably counts newlines and semicolons to estimate the size.

Linus