re PR target/24036 ([e500] ICE in subreg_offset_representable_p, at rtlanal.c:3143)

2006-12-01  Joseph Myers  <joseph@codesourcery.com>
            David Edelsohn  <edelsohn@gnu.org>

	PR target/24036
	* doc/tm.texi (HARD_REGNO_NREGS_HAS_PADDING,
	HARD_REGNO_NREGS_WITH_PADDING): Document new target macros.
	* defaults.h (HARD_REGNO_NREGS_HAS_PADDING,
	HARD_REGNO_NREGS_WITH_PADDING): Define.
	* config/i386/i386.h (HARD_REGNO_NREGS_HAS_PADDING,
	HARD_REGNO_NREGS_WITH_PADDING): Define.
	* rtlanal.c (subreg_regno_offset, subreg_offset_representable_p):
	Use new macros to detect modes with holes; do not look at integer
	units.
	(subreg_offset_representable_p): Check for and disallow cases
	where the modes use different numbers of bits from registers.
	* config/rs6000/rs6000.c (rs6000_emit_move): Handle TFmode
	constant for soft-float.
	(rs6000_hard_regno_nregs): Use UNITS_PER_FP_WORD for e500 GPRs
	containing doubles.
	(rs6000_split_multireg_move): Use DFmode reg_mode for TFmode moves
	in E500 double case.
	* config/rs6000/rs6000.md (movtf): Allow soft-float.
	(movtf_softfloat): New.

Co-Authored-By: David Edelsohn <edelsohn@gnu.org>

From-SVN: r119395

1 files changed, 27 insertions, 0 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 2a21a58..634f5f1 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -1978,6 +1978,33 @@ definition of this macro is
 @end smallexample
 @end defmac
 
+@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode})
+A C expression that is nonzero if a value of mode @var{mode}, stored
+in memory, ends with padding that causes it to take up more space than
+in registers starting at register number @var{regno} (as determined by
+multiplying GCC's notion of the size of the register when containing
+this mode by the number of registers returned by
+@code{HARD_REGNO_NREGS}).  By default this is zero.
+
+For example, if a floating-point value is stored in three 32-bit
+registers but takes up 128 bits in memory, then this would be
+nonzero.
+
+This macros only needs to be defined if there are cases where
+@code{subreg_regno_offset} and @code{subreg_offset_representable_p}
+would otherwise wrongly determine that a @code{subreg} can be
+represented by an offset to the register number, when in fact such a
+@code{subreg} would contain some of the padding not stored in
+registers and so not be representable.
+@end defmac
+
+@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode})
+For values of @var{regno} and @var{mode} for which
+@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression
+returning the greater number of registers required to hold the value
+including any padding.  In the example above, the value would be four.
+@end defmac
+
 @defmac REGMODE_NATURAL_SIZE (@var{mode})
 Define this macro if the natural size of registers that hold values
 of mode @var{mode} is not the word size.  It is a C expression that