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riscv-gcc-1
Commit 87ba6944 by Michael Hayes Committed by Michael Hayes
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c4x.c (legitimize_operands): Use rtx_cost to determine if it is worthwhile… 

c4x.c (legitimize_operands): Use rtx_cost to determine if it is worthwhile forcing a constant into a register.

	* config/c4x/c4x.c (legitimize_operands): Use rtx_cost
	to determine if it is worthwhile forcing a constant into a register.
	* config/c4x/c4x.h (CONST_COSTS): An integer value of 255 or 65535
	used with a logical and or an integer value of 16 or 24 used with
	a right shift has zero cost on the C40.

From-SVN: r26529
parent 695ab36a
Showing with 38 additions and 10 deletions
gcc/ChangeLog
Sun Apr 18 17:24:10 1999 Michael Hayes <m.hayes@elec.canterbury.ac.nz>
* config/c4x/c4x.c (legitimize_operands): Use rtx_cost
to determine if it is worthwhile forcing a constant into a register.
* config/c4x/c4x.h (CONST_COSTS): An integer value of 255 or 65535
used with a logical and or an integer value of 16 or 24 used with
a right shift has zero cost on the C40.
Sat Apr 17 21:30:11 1999 Bernd Schmidt <crux@pool.informatik.rwth-aachen.de>
* gcse.c (compute_local_properties): If setp is nonzero, clear
......
gcc/config/c4x/c4x.c
......@@ -3582,6 +3582,11 @@ c4x_valid_operands (code, operands, mode, force)
/* Any valid memory operand screened by src_operand is OK. */
case MEM:
#if 0
if (code2 != REG)
return 0;
#endif
break;
/* After CSE, any remaining (ADDRESSOF:P reg) gets converted
into a stack slot memory address comprising a PLUS and a
......@@ -3644,10 +3649,9 @@ legitimize_operands (code, operands, mode)
if (! reload_in_progress
&& TARGET_HOIST
&& optimize > 0
&& ((GET_CODE (operands[1]) == CONST_INT
&& ! c4x_J_constant (operands[1])
&& INTVAL (operands[1]) != 0)
|| GET_CODE (operands[1]) == CONST_DOUBLE))
&& GET_CODE (operands[1]) == CONST_INT
&& preserve_subexpressions_p ()
&& rtx_cost (operands[1], code) > 1)
operands[1] = force_reg (mode, operands[1]);
if (! reload_in_progress
......@@ -3661,11 +3665,11 @@ legitimize_operands (code, operands, mode)
opportunities. */
if (! reload_in_progress
&& ! ((code == PLUS || code == MINUS) && mode == Pmode)
&& (TARGET_HOIST && optimize > 1
&& ((GET_CODE (operands[2]) == CONST_INT
&& ! c4x_J_constant (operands[2])
&& INTVAL (operands[2]) != 0)
|| GET_CODE (operands[2]) == CONST_DOUBLE)))
&& TARGET_HOIST
&& optimize > 1
&& GET_CODE (operands[2]) == CONST_INT
&& preserve_subexpressions_p ()
&& rtx_cost (operands[2], code) > 1)
operands[2] = force_reg (mode, operands[2]);
/* We can get better code on a C30 if we force constant shift counts
......
gcc/config/c4x/c4x.h
......@@ -1763,7 +1763,13 @@ extern void c4x_encode_section_info ();
Some small integers are effectively free for the C40. We should
also consider if we are using the small memory model. With
the big memory model we require an extra insn for a constant
loaded from memory. */
loaded from memory.
This is used by expand_binop to decide whether to force a constant
into a register. If the cost is greater than 2 and the constant
is used within a short loop, it gets forced into a register.
Ideally, there should be some weighting as to how mnay times it is used
within the loop. */
#define SHIFT_CODE_P(C) ((C) == ASHIFT || (C) == ASHIFTRT || (C) == LSHIFTRT)
......@@ -1776,6 +1782,16 @@ extern void c4x_encode_section_info ();
case CONST_INT: \
if (c4x_J_constant (RTX)) \
return 0; \
if (! TARGET_C3X \
&& OUTER_CODE == AND \
&& GET_CODE (RTX) == CONST_INT \
&& (INTVAL (RTX) == 255 || INTVAL (RTX) == 65535)) \
return 0; \
if (! TARGET_C3X \
&& (OUTER_CODE == ASHIFTRT || OUTER_CODE == LSHIFTRT) \
&& GET_CODE (RTX) == CONST_INT \
&& (INTVAL (RTX) == 16 || INTVAL (RTX) == 24)) \
return 0; \
if (TARGET_C3X && SHIFT_CODE_P (OUTER_CODE)) \
return 3; \
if (LOGICAL_CODE_P (OUTER_CODE) \
......
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