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[PATCH]: Fix reg rename optimization on HC11/HC12
- From: Stephane Carrez <stcarrez at nerim dot fr>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 10 Mar 2003 23:14:06 +0100
- Subject: [PATCH]: Fix reg rename optimization on HC11/HC12
Hi!
The reg rename optimization does very bad things on HC11 because the two address
registers X and Y are not equivalent in terms of cost (Y reg needs one more insn byte thus
making the insn larger and slower). I've added the (undocumented?) HARD_REGNO_RENAME_OK
to tell reg rename about that (and it works great now).
Committed on 3_3 and mainline.
Stephane
2003-03-10 Stephane Carrez <stcarrez at nerim dot fr>
* config/m68hc11/m68hc11.h (HARD_REGNO_RENAME_OK): Define.
* config/m68hc11/m68hc11-protos.h (m68hc11_hard_regno_rename_ok):
Declare.
* config/m68hc11/m68hc11.c (m68hc11_hard_regno_rename_ok): New function
for reg rename optimization to avoid using Z and Y registers.
Index: config/m68hc11/m68hc11-protos.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68hc11/m68hc11-protos.h,v
retrieving revision 1.18.14.3
diff -u -p -r1.18.14.3 m68hc11-protos.h
--- config/m68hc11/m68hc11-protos.h 5 Mar 2003 21:34:28 -0000 1.18.14.3
+++ config/m68hc11/m68hc11-protos.h 10 Mar 2003 22:01:52 -0000
@@ -24,6 +24,7 @@ extern int m68hc11_override_options PARA
extern int m68hc11_optimization_options PARAMS((int,int));
extern void m68hc11_conditional_register_usage PARAMS((void));
extern int hard_regno_mode_ok PARAMS((int, enum machine_mode));
+extern int m68hc11_hard_regno_rename_ok PARAMS((int, int));
extern int m68hc11_total_frame_size PARAMS((void));
extern int m68hc11_initial_frame_pointer_offset PARAMS((void));
Index: config/m68hc11/m68hc11.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68hc11/m68hc11.c,v
retrieving revision 1.56.4.8
diff -u -p -r1.56.4.8 m68hc11.c
--- config/m68hc11/m68hc11.c 10 Mar 2003 21:29:31 -0000 1.56.4.8
+++ config/m68hc11/m68hc11.c 10 Mar 2003 22:01:52 -0000
@@ -384,6 +384,23 @@ hard_regno_mode_ok (regno, mode)
}
}
+int
+m68hc11_hard_regno_rename_ok (reg1, reg2)
+ int reg1, reg2;
+{
+ /* Don't accept renaming to Z register. We will replace it to
+ X,Y or D during machine reorg pass. */
+ if (reg2 == HARD_Z_REGNUM)
+ return 0;
+
+ /* Don't accept renaming D,X to Y register as the code will be bigger. */
+ if (TARGET_M6811 && reg2 == HARD_Y_REGNUM
+ && (D_REGNO_P (reg1) || X_REGNO_P (reg1)))
+ return 0;
+
+ return 1;
+}
+
enum reg_class
preferred_reload_class (operand, class)
rtx operand;
Index: config/m68hc11/m68hc11.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/m68hc11/m68hc11.h,v
retrieving revision 1.55.4.6
diff -u -p -r1.55.4.6 m68hc11.h
--- config/m68hc11/m68hc11.h 10 Mar 2003 21:51:53 -0000 1.55.4.6
+++ config/m68hc11/m68hc11.h 10 Mar 2003 22:01:53 -0000
@@ -796,6 +796,12 @@ extern enum reg_class m68hc11_tmp_regs_c
#define SMALL_REGISTER_CLASSES 1
+/* A C expression that is nonzero if hard register number REGNO2 can be
+ considered for use as a rename register for REGNO1 */
+
+#define HARD_REGNO_RENAME_OK(REGNO1,REGNO2) \
+ m68hc11_hard_regno_rename_ok ((REGNO1), (REGNO2))
+
/* A C expression whose value is nonzero if pseudos that have been
assigned to registers of class CLASS would likely be spilled
because registers of CLASS are needed for spill registers.