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Re: [PATCH 3/9] Add option -moutline-msabi-xlogues
On 11/22/2016 10:19 PM, Daniel Santos wrote:
diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
index 9eef558..f556978 100644
--- a/gcc/config/i386/i386.opt
+++ b/gcc/config/i386/i386.opt
@@ -528,6 +528,11 @@ Enum(calling_abi) String(sysv) Value(SYSV_ABI)
EnumValue
Enum(calling_abi) String(ms) Value(MS_ABI)
+moutline-msabi-xlogues
+Target Report Mask(OUTLINE_MSABI_XLOGUES) Save
+Reduces function size by using out-of-line stubs to save & restore registers
+clobberd by differences in Microsoft and System V ABIs.
+
Just as a suggestion (I'm not an i386 maintainer), I'd recommend
spelling the name of this option -mno-inline-msabi-xlogues instead of
-moutline-msabi-xlogues, and making the default -minline-msabi-xlogues.
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8e2f466..4706085 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -25004,6 +25004,15 @@ You can control this behavior for specific functions by
using the function attributes @code{ms_abi} and @code{sysv_abi}.
@xref{Function Attributes}.
+@item -moutline-msabi-xlogues
+@itemx -mno-outline-msabi-xlogues
By convention, we only list the option form that is not the default....
+@opindex moutline-msabi-xlogues
...but we should have index entries for both.
+Due to differences in 64-bit ABIs, any Microsoft ABI function that calls a
+SysV ABI function must consider RSI, RDI and XMM6-15 as clobbered, emitting
+fairly lengthy prologues & epilogues. This option generates prologues &
+epilogues that instead call stubs in libgcc to perform these saves & restores,
+thus reducing function size at the cost of a few extra instructions.
Please use the word "and" in all three locations here, instead of "&".
-Sandra