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* [Bug c/53354] New: %z# asm specifier could be extended to support immediate constraints
@ 2012-05-15 1:40 svfuerst at gmail dot com
2012-05-15 1:47 ` [Bug target/53354] " pinskia at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: svfuerst at gmail dot com @ 2012-05-15 1:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53354
Bug #: 53354
Summary: %z# asm specifier could be extended to support
immediate constraints
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: svfuerst@gmail.com
It would be nice if %z# would work with immediate asm constraints:
void foo(void)
{
#if 1
int x = 1;
asm("mov%z0 %0, bar":: "r" (x));
#else
asm("mov%z0 %0, bar":: "i" (1));
#endif
}
The first option isn't optimal as an extra register is needed. If the second
is tried, gcc exits with "error: invalid 'asm': invalid operand type used with
operand code 'z'"
Typically, to work around this, people use a switch statement based on the size
of the immediate, and manually copy the code for sizes of 1, 2, 4, 8 byte
registers. It would be simpler if the bulky switch statements weren't
necessary.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug target/53354] %z# asm specifier could be extended to support immediate constraints
2012-05-15 1:40 [Bug c/53354] New: %z# asm specifier could be extended to support immediate constraints svfuerst at gmail dot com
@ 2012-05-15 1:47 ` pinskia at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2012-05-15 1:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53354
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Component|c |target
Resolution| |INVALID
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-05-15 01:42:09 UTC ---
We don't want to this because const_int for RTL don't have a mode so the
back-end does not know what extension to use here.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-05-15 1:40 [Bug c/53354] New: %z# asm specifier could be extended to support immediate constraints svfuerst at gmail dot com
2012-05-15 1:47 ` [Bug target/53354] " pinskia at gcc dot gnu.org
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