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Commit a5f42165 by Nick Clifton Committed by Nick Clifton
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Add Jim's patches to improve reload behaviour. 

From-SVN: r22561
parent f916eeb6
Showing with 67 additions and 9 deletions
gcc/ChangeLog
Wed Sep 23 16:22:01 1998 Nick Clifton <nickc@cygnus.com>
* config/arm/thumb.h: The following patches were made by Jim Wilson:
(enum reg_class): Add NONARG_LO_REGS support.
(REG_CLASS_NAMES, REG_CLASS_CONTENTS, REGNO_REG_CLASS,
PREFERRED_RELOAD_CLASS, SECONDARY_RELOAD_CLASS): Likewise.
(GO_IF_LEGITIMATE_ADDRESS): Disable REG+REG addresses before reload
completes. Re-enable HImode REG+OFFSET addresses.
(LEGITIMIZE_RELOAD_ADDRESS): Define.
* expmed.c (extract_bit_field): Add comment from Jim Wilson.
Wed Sep 23 13:26:02 1998 Richard Henderson <rth@cygnus.com>
......
gcc/config/arm/thumb.h
......@@ -472,9 +472,15 @@ extern char * structure_size_string;
#define MODES_TIEABLE_P(MODE1,MODE2) 1
/* The NOARG_LO_REGS class is the set of LO_REGS that are not used for passing
arguments to functions. These are the registers that are available for
spilling during reload. The code in reload1.c:init_reload() will detect this
class and place it into 'reload_address_base_reg_class'. */
enum reg_class
{
NO_REGS,
NONARG_LO_REGS,
LO_REGS,
STACK_REG,
BASE_REGS,
......@@ -490,6 +496,7 @@ enum reg_class
#define REG_CLASS_NAMES \
{ \
"NO_REGS", \
"NONARG_LO_REGS", \
"LO_REGS", \
"STACK_REG", \
"BASE_REGS", \
......@@ -500,6 +507,7 @@ enum reg_class
#define REG_CLASS_CONTENTS \
{ \
0x00000, \
0x000f0, \
0x000ff, \
0x02000, \
0x020ff, \
......@@ -509,7 +517,8 @@ enum reg_class
#define REGNO_REG_CLASS(REGNO) \
((REGNO) == STACK_POINTER_REGNUM ? STACK_REG \
: (REGNO) < 8 ? LO_REGS \
: (REGNO) < 8 ? ((REGNO) < 4 ? LO_REGS \
: NONARG_LO_REGS) \
: HI_REGS)
#define BASE_REG_CLASS BASE_REGS
......@@ -555,8 +564,15 @@ enum reg_class
abort. Alternatively, this could be fixed by modifying BASE_REG_CLASS
to be LO_REGS instead of BASE_REGS. It is not clear what affect this
change would have. */
/* ??? This looks even more suspiciously wrong. PREFERRED_RELOAD_CLASS
must always return a strict subset of the input class. Just blindly
returning LO_REGS is safe only if the input class is a superset of LO_REGS,
but there is no check for this. Added another exception for NONARG_LO_REGS
because it is not a superset of LO_REGS. */
/* ??? We now use NONARG_LO_REGS for caller_save_spill_class, so the
comments about BASE_REGS are now obsolete. */
#define PREFERRED_RELOAD_CLASS(X,CLASS) \
((CLASS) == BASE_REGS ? (CLASS) \
((CLASS) == BASE_REGS || (CLASS) == NONARG_LO_REGS ? (CLASS) \
: LO_REGS)
/*
((CONSTANT_P ((X)) && GET_CODE ((X)) != CONST_INT \
......@@ -565,9 +581,10 @@ enum reg_class
&& (unsigned HOST_WIDE_INT) INTVAL ((X)) > 255) ? NO_REGS \
: LO_REGS) */
/* Must leave BASE_REGS reloads alone, see comment above. */
/* Must leave BASE_REGS and NONARG_LO_REGS reloads alone, see comment
above. */
#define SECONDARY_RELOAD_CLASS(CLASS,MODE,X) \
((CLASS) != LO_REGS && (CLASS) != BASE_REGS \
((CLASS) != LO_REGS && (CLASS) != BASE_REGS && (CLASS) != NONARG_LO_REGS \
? ((true_regnum (X) == -1 ? LO_REGS \
: (true_regnum (X) + HARD_REGNO_NREGS (0, MODE) > 8) ? LO_REGS \
: NO_REGS)) \
......@@ -885,6 +902,16 @@ int thumb_shiftable_const ();
else if (GET_CODE (X) == PLUS) \
{ \
/* REG+REG address can be any two index registers. */ \
/* ??? REG+REG addresses have been completely disabled before \
reload completes, because we do not have enough available \
reload registers. We only have 3 guaranteed reload registers \
(NONARG_LO_REGS - the frame pointer), but we need at least 4 \
to support REG+REG addresses. We have left them enabled after \
reload completes, in the hope that reload_cse_regs and related \
routines will be able to create them after the fact. It is \
probably possible to support REG+REG addresses with additional \
reload work, but I do not not have enough time to attempt such \
a change at this time. */ \
/* ??? Normally checking the mode here is wrong, since it isn't \
impossible to use REG+REG with DFmode. However, the movdf \
pattern requires offsettable addresses, and REG+REG is not \
......@@ -898,14 +925,14 @@ int thumb_shiftable_const ();
will be replaced with STACK, and SP relative addressing only \
permits SP+OFFSET. */ \
if (GET_MODE_SIZE (MODE) <= 4 \
/* ??? See comment above. */ \
&& reload_completed \
&& GET_CODE (XEXP (X, 0)) == REG \
&& GET_CODE (XEXP (X, 1)) == REG \
&& XEXP (X, 0) != frame_pointer_rtx \
&& XEXP (X, 1) != frame_pointer_rtx \
/* CYGNUS LOCAL nickc */ \
&& XEXP (X, 0) != virtual_stack_vars_rtx \
&& XEXP (X, 1) != virtual_stack_vars_rtx \
/* END CYGNUS LOCAL */ \
&& REG_OK_FOR_INDEX_P (XEXP (X, 0)) \
&& REG_OK_FOR_INDEX_P (XEXP (X, 1))) \
goto WIN; \
......@@ -913,9 +940,6 @@ int thumb_shiftable_const ();
else if (GET_CODE (XEXP (X, 0)) == REG \
&& (REG_OK_FOR_INDEX_P (XEXP (X, 0)) \
|| XEXP (X, 0) == arg_pointer_rtx) \
/* CYGNUS LOCAL nickc */ \
&& GET_MODE_SIZE (MODE) != 2 \
/* END CYGNUS LOCAL */ \
&& GET_CODE (XEXP (X, 1)) == CONST_INT \
&& LEGITIMATE_OFFSET (MODE, INTVAL (XEXP (X, 1)))) \
goto WIN; \
......@@ -933,6 +957,32 @@ int thumb_shiftable_const ();
} \
}
/* ??? If an HImode FP+large_offset address is converted to an HImode
SP+large_offset address, then reload won't know how to fix it. It sees
only that SP isn't valid for HImode, and so reloads the SP into an index
register, but the resulting address is still invalid because the offset
is too big. We fix it here instead by reloading the entire address. */
/* We could probably achieve better results by defining PROMOTE_MODE to help
cope with the variances between the Thumb's signed and unsigned byte and
halfword load instructions. */
#define LEGITIMIZE_RELOAD_ADDRESS(X,MODE,OPNUM,TYPE,IND_LEVELS,WIN) \
{ \
if (GET_CODE (X) == PLUS \
&& GET_MODE_SIZE (MODE) < 4 \
&& GET_CODE (XEXP (X, 0)) == REG \
&& XEXP (X, 0) == stack_pointer_rtx \
&& GET_CODE (XEXP (X, 1)) == CONST_INT \
&& ! LEGITIMATE_OFFSET (MODE, INTVAL (XEXP (X, 1)))) \
{ \
rtx orig_X = X; \
X = copy_rtx (X); \
push_reload (orig_X, NULL_RTX, &X, NULL_PTR, \
reload_address_base_reg_class, \
Pmode, VOIDmode, 0, 0, OPNUM, TYPE); \
goto WIN; \
} \
}
#define GO_IF_MODE_DEPENDENT_ADDRESS(ADDR,LABEL)
#define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN)
......
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