diff options
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/invoke.texi | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 15068da..33a7ed2 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -16256,6 +16256,19 @@ the profiling functions as nops. This is useful when they should be patched in later dynamically. This is likely only useful together with @option{-mrecord-mcount}. +@item -mskip-rax-setup +@itemx -mno-skip-rax-setup +@opindex mskip-rax-setup +When generating code for the x86-64 architecture with SSE extensions +disabled, @option{-skip-rax-setup} can be used to skip setting up RAX +register when there are no variable arguments passed in vector registers. + +@strong{Warning:} Since RAX register is used to avoid unnecessarily +saving vector registers on stack when passing variable arguments, the +impacts of this option are callees may waste some stack space, +misbehave or jump to a random location. GCC 4.4 or newer don't have +those issues, regardless the RAX register value. + @item -m8bit-idiv @itemx -mno-8bit-idiv @opindex 8bit-idiv |