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Re: [PATCH] gen_lowpart_no_emit RTL hook
- From: Paolo Bonzini <bonzini at gnu dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 21 Mar 2005 10:36:32 +0100
- Subject: Re: [PATCH] gen_lowpart_no_emit RTL hook
- References: <423E9452.4070705@lu.unisi.ch>
So, this patch turns this ``common'' (it occurs 3 times) pattern found
in simplify-rtx.c, into a different RTL hook:
Here is the patch.
Paolo
2005-03-19 Paolo Bonzini <bonzini@gnu.org>
* rtl.h (struct rtx_hooks): Add gen_lowpart_no_emit.
* rtlhooks.c (gen_lowpart_no_emit_general): New.
* rtlhooks-def.h (gen_lowpart_no_emit_general): Declare.
(RTL_HOOKS_GEN_LOWPART_NO_EMIT): New.
* simplify-rtx.c (simplify_binary_operation_1): Use it.
--- rtl.h.old 2005-03-19 12:58:58.000000000 +0100
+++ rtl.h 2005-03-19 13:00:14.000000000 +0100
@@ -2191,6 +2191,7 @@ extern void sms_schedule (FILE *);
struct rtl_hooks
{
rtx (*gen_lowpart) (enum machine_mode, rtx);
+ rtx (*gen_lowpart_no_emit) (enum machine_mode, rtx);
rtx (*reg_nonzero_bits) (rtx, enum machine_mode, rtx, enum machine_mode,
unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT *);
rtx (*reg_num_sign_bit_copies) (rtx, enum machine_mode, rtx, enum machine_mode,
--- simplify-rtx.c.old 2005-03-19 12:22:04.000000000 +0100
+++ simplify-rtx.c 2005-03-19 12:51:16.000000000 +0100
@@ -1704,15 +1704,7 @@ simplify_binary_operation_1 (enum rtx_co
: const0_rtx;
/* x/1 is x. */
if (trueop1 == const1_rtx)
- {
- /* Handle narrowing UDIV. */
- rtx x = gen_lowpart_common (mode, op0);
- if (x)
- return x;
- if (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
- return gen_lowpart_SUBREG (mode, op0);
- return op0;
- }
+ return rtl_hooks.gen_lowpart_no_emit (mode, op0);
/* Convert divide by power of two into shift. */
if (GET_CODE (trueop1) == CONST_INT
&& (val = exact_log2 (INTVAL (trueop1))) > 0)
@@ -1768,22 +1760,11 @@ simplify_binary_operation_1 (enum rtx_co
: const0_rtx;
/* x/1 is x. */
if (trueop1 == const1_rtx)
- {
- /* Handle narrowing DIV. */
- rtx x = gen_lowpart_common (mode, op0);
- if (x)
- return x;
- if (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
- return gen_lowpart_SUBREG (mode, op0);
- return op0;
- }
+ return rtl_hooks.gen_lowpart_no_emit (mode, op0);
/* x/-1 is -x. */
if (trueop1 == constm1_rtx)
{
- rtx x = gen_lowpart_common (mode, op0);
- if (!x)
- x = (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
- ? gen_lowpart_SUBREG (mode, op0) : op0;
+ rtx x = rtl_hooks.gen_lowpart_no_emit (mode, op0);
return simplify_gen_unary (NEG, mode, x, mode);
}
}
--- rtlhooks.c.old 2005-03-19 13:02:17.000000000 +0100
+++ rtlhooks.c 2005-03-19 12:52:40.000000000 +0100
@@ -79,6 +79,19 @@ gen_lowpart_general (enum machine_mode m
}
}
+/* Similar to gen_lowpart, but cannot emit any instruction via
+ copy_to_reg or force_reg. Mainly used in simplify-rtx.c. */
+rtx
+gen_lowpart_no_emit_general (enum machine_mode mode, rtx x)
+{
+ rtx result = gen_lowpart_common (mode, x);
+ if (result)
+ return result;
+ if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode)
+ return gen_lowpart_SUBREG (mode, x);
+ return x;
+}
+
rtx
reg_num_sign_bit_copies_general (rtx x ATTRIBUTE_UNUSED,
enum machine_mode mode ATTRIBUTE_UNUSED,
--- rtlhooks-def.h.old 2005-03-19 13:02:04.000000000 +0100
+++ rtlhooks-def.h 2005-03-19 12:47:33.000000000 +0100
@@ -24,17 +24,20 @@ Boston, MA 02111-1307, USA. */
#include "rtl.h"
#define RTL_HOOKS_GEN_LOWPART gen_lowpart_general
+#define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_no_emit_general
#define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_general
#define RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES reg_num_sign_bit_copies_general
/* The structure is defined in rtl.h. */
#define RTL_HOOKS_INITIALIZER { \
RTL_HOOKS_GEN_LOWPART, \
+ RTL_HOOKS_GEN_LOWPART_NO_EMIT, \
RTL_HOOKS_REG_NONZERO_REG_BITS, \
RTL_HOOKS_REG_NUM_SIGN_BIT_COPIES, \
}
extern rtx gen_lowpart_general (enum machine_mode, rtx);
+extern rtx gen_lowpart_no_emit_general (enum machine_mode, rtx);
extern rtx reg_nonzero_bits_general (rtx, enum machine_mode, rtx,
enum machine_mode,
unsigned HOST_WIDE_INT,