From abd535b681d7bba79c3f8bc85451822fe7e4f8d0 Mon Sep 17 00:00:00 2001
From: Bernd Schmidt <bernds@cygnus.co.uk>
Date: Wed, 25 Aug 1999 03:30:45 +0000
Subject: [PATCH] gcse.c (cprop_jump): New function, broken out of cprop_insn.
* gcse.c (cprop_jump): New function, broken out of cprop_insn.
(cprop_cc0_jump): New function.
(cprop_insn): Break out new function cprop_jump and use it.
Also use cprop_cc0_jump for machines with CC0.
(cprop): Don't crash if cprop_insn turned the insn into a NOTE.
From-SVN: r28834
---
gcc/ChangeLog | 6 ++
gcc/gcse.c | 207 ++++++++++++++++++++++++++++++++------------------
2 files changed, 137 insertions(+), 76 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 76497478595c..cb72d9566275 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -110,6 +110,12 @@ Tue Aug 24 09:32:07 1999 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
Tue Aug 24 12:35:20 1999 Bernd Schmidt <bernds@cygnus.co.uk>
+ * gcse.c (cprop_jump): New function, broken out of cprop_insn.
+ (cprop_cc0_jump): New function.
+ (cprop_insn): Break out new function cprop_jump and use it.
+ Also use cprop_cc0_jump for machines with CC0.
+ (cprop): Don't crash if cprop_insn turned the insn into a NOTE.
+
* tree.h (current_function_calls_setjmp,
current_function_calls_longjmp): Delete declarations.
* dsp16xx.c: Include "function.h".
diff --git a/gcc/gcse.c b/gcc/gcse.c
index 6a248bc51e10..36b376b68670 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -310,6 +310,10 @@ static char can_copy_p[(int) NUM_MACHINE_MODES];
/* Non-zero if can_copy_p has been initialized. */
static int can_copy_init_p;
+struct reg_use {
+ rtx reg_rtx;
+};
+
/* Hash table of expressions. */
struct expr
@@ -572,6 +576,8 @@ static void compute_cprop_data PROTO ((void));
static void find_used_regs PROTO ((rtx));
static int try_replace_reg PROTO ((rtx, rtx, rtx));
static struct expr *find_avail_set PROTO ((int, rtx));
+static int cprop_jump PROTO((rtx, rtx, struct reg_use *, rtx));
+static int cprop_cc0_jump PROTO((rtx, struct reg_use *, rtx));
static int cprop_insn PROTO ((rtx, int));
static int cprop PROTO ((int));
static int one_cprop_pass PROTO ((int, int));
@@ -3532,10 +3538,6 @@ compute_cprop_data ()
/* Copy/constant propagation. */
-struct reg_use {
- rtx reg_rtx;
-};
-
/* Maximum number of register uses in an insn that we handle. */
#define MAX_USES 8
@@ -3666,6 +3668,114 @@ find_avail_set (regno, insn)
return set;
}
+/* Subroutine of cprop_insn that tries to propagate constants into
+ JUMP_INSNS. INSN must be a conditional jump; COPY is a copy of it
+ that we can use for substitutions.
+ REG_USED is the use we will try to replace, SRC is the constant we
+ will try to substitute for it.
+ Returns nonzero if a change was made. */
+static int
+cprop_jump (insn, copy, reg_used, src)
+ rtx insn, copy;
+ struct reg_use *reg_used;
+ rtx src;
+{
+ rtx set = PATTERN (copy);
+ rtx temp;
+
+ /* Replace the register with the appropriate constant. */
+ replace_rtx (SET_SRC (set), reg_used->reg_rtx, src);
+
+ temp = simplify_ternary_operation (GET_CODE (SET_SRC (set)),
+ GET_MODE (SET_SRC (set)),
+ GET_MODE (XEXP (SET_SRC (set), 0)),
+ XEXP (SET_SRC (set), 0),
+ XEXP (SET_SRC (set), 1),
+ XEXP (SET_SRC (set), 2));
+
+ /* If no simplification can be made, then try the next
+ register. */
+ if (temp == 0)
+ return 0;
+
+ SET_SRC (set) = temp;
+
+ /* That may have changed the structure of TEMP, so
+ force it to be rerecognized if it has not turned
+ into a nop or unconditional jump. */
+
+ INSN_CODE (copy) = -1;
+ if ((SET_DEST (set) == pc_rtx
+ && (SET_SRC (set) == pc_rtx
+ || GET_CODE (SET_SRC (set)) == LABEL_REF))
+ || recog (PATTERN (copy), copy, NULL) >= 0)
+ {
+ /* This has either become an unconditional jump
+ or a nop-jump. We'd like to delete nop jumps
+ here, but doing so confuses gcse. So we just
+ make the replacement and let later passes
+ sort things out. */
+ PATTERN (insn) = set;
+ INSN_CODE (insn) = -1;
+
+ /* One less use of the label this insn used to jump to
+ if we turned this into a NOP jump. */
+ if (SET_SRC (set) == pc_rtx && JUMP_LABEL (insn) != 0)
+ --LABEL_NUSES (JUMP_LABEL (insn));
+
+ /* If this has turned into an unconditional jump,
+ then put a barrier after it so that the unreachable
+ code will be deleted. */
+ if (GET_CODE (SET_SRC (set)) == LABEL_REF)
+ emit_barrier_after (insn);
+
+ run_jump_opt_after_gcse = 1;
+
+ const_prop_count++;
+ if (gcse_file != NULL)
+ {
+ int regno = REGNO (reg_used->reg_rtx);
+ fprintf (gcse_file, "CONST-PROP: Replacing reg %d in insn %d with constant ",
+ regno, INSN_UID (insn));
+ print_rtl (gcse_file, src);
+ fprintf (gcse_file, "\n");
+ }
+ return 1;
+ }
+ return 0;
+}
+
+#ifdef HAVE_cc0
+/* Subroutine of cprop_insn that tries to propagate constants into
+ JUMP_INSNS for machines that have CC0. INSN is a single set that
+ stores into CC0; the insn following it is a conditional jump.
+ REG_USED is the use we will try to replace, SRC is the constant we
+ will try to substitute for it.
+ Returns nonzero if a change was made. */
+static int
+cprop_cc0_jump (insn, reg_used, src)
+ rtx insn;
+ struct reg_use *reg_used;
+ rtx src;
+{
+ rtx jump = NEXT_INSN (insn);
+ rtx copy = copy_rtx (jump);
+ rtx set = PATTERN (copy);
+
+ /* We need to copy the source of the cc0 setter, as cprop_jump is going to
+ substitute into it. */
+ replace_rtx (SET_SRC (set), cc0_rtx, copy_rtx (SET_SRC (PATTERN (insn))));
+ if (! cprop_jump (jump, copy, reg_used, src))
+ return 0;
+
+ /* If we succeeded, delete the cc0 setter. */
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ return 1;
+ }
+#endif
+
/* Perform constant and copy propagation on INSN.
The result is non-zero if a change was made. */
@@ -3743,80 +3853,23 @@ cprop_insn (insn, alter_jumps)
code, we can extend this as necessary over time.
Right now the insn in question must look like
-
- (set (pc) (if_then_else ...))
-
- Note this does not currently handle machines which use cc0. */
+ (set (pc) (if_then_else ...)) */
else if (alter_jumps
&& GET_CODE (insn) == JUMP_INSN
&& condjump_p (insn)
&& ! simplejump_p (insn))
- {
- /* We want a copy of the JUMP_INSN so we can modify it
- in-place as needed without effecting the original. */
- rtx copy = copy_rtx (insn);
- rtx set = PATTERN (copy);
- rtx temp;
-
- /* Replace the register with the appropriate constant. */
- replace_rtx (SET_SRC (set), reg_used->reg_rtx, src);
-
- temp = simplify_ternary_operation (GET_CODE (SET_SRC (set)),
- GET_MODE (SET_SRC (set)),
- GET_MODE (XEXP (SET_SRC (set), 0)),
- XEXP (SET_SRC (set), 0),
- XEXP (SET_SRC (set), 1),
- XEXP (SET_SRC (set), 2));
-
- /* If no simplification can be made, then try the next
- register. */
- if (temp)
- SET_SRC (set) = temp;
- else
- continue;
-
- /* That may have changed the structure of TEMP, so
- force it to be rerecognized if it has not turned
- into a nop or unconditional jump. */
-
- INSN_CODE (copy) = -1;
- if ((SET_DEST (set) == pc_rtx
- && (SET_SRC (set) == pc_rtx
- || GET_CODE (SET_SRC (set)) == LABEL_REF))
- || recog (PATTERN (copy), copy, NULL) >= 0)
- {
- /* This has either become an unconditional jump
- or a nop-jump. We'd like to delete nop jumps
- here, but doing so confuses gcse. So we just
- make the replacement and let later passes
- sort things out. */
- PATTERN (insn) = set;
- INSN_CODE (insn) = -1;
-
- /* One less use of the label this insn used to jump to
- if we turned this into a NOP jump. */
- if (SET_SRC (set) == pc_rtx && JUMP_LABEL (insn) != 0)
- --LABEL_NUSES (JUMP_LABEL (insn));
-
- /* If this has turned into an unconditional jump,
- then put a barrier after it so that the unreachable
- code will be deleted. */
- if (GET_CODE (SET_SRC (set)) == LABEL_REF)
- emit_barrier_after (insn);
-
- run_jump_opt_after_gcse = 1;
-
- changed = 1;
- const_prop_count++;
- if (gcse_file != NULL)
- {
- fprintf (gcse_file, "CONST-PROP: Replacing reg %d in insn %d with constant ",
- regno, INSN_UID (insn));
- print_rtl (gcse_file, src);
- fprintf (gcse_file, "\n");
- }
- }
- }
+ changed |= cprop_jump (insn, copy_rtx (insn), reg_used, src);
+#ifdef HAVE_cc0
+ /* Similar code for machines that use a pair of CC0 setter and
+ conditional jump insn. */
+ else if (alter_jumps
+ && GET_CODE (PATTERN (insn)) == SET
+ && SET_DEST (PATTERN (insn)) == cc0_rtx
+ && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN
+ && condjump_p (NEXT_INSN (insn))
+ && ! simplejump_p (NEXT_INSN (insn)))
+ changed |= cprop_cc0_jump (insn, reg_used, src);
+#endif
}
else if (GET_CODE (src) == REG
&& REGNO (src) >= FIRST_PSEUDO_REGISTER
@@ -3879,8 +3932,10 @@ cprop (alter_jumps)
changed |= cprop_insn (insn, alter_jumps);
/* Keep track of everything modified by this insn. */
- /* ??? Need to be careful w.r.t. mods done to INSN. */
- mark_oprs_set (insn);
+ /* ??? Need to be careful w.r.t. mods done to INSN. Don't
+ call mark_oprs_set if we turned the insn into a NOTE. */
+ if (GET_CODE (insn) != NOTE)
+ mark_oprs_set (insn);
}
}
}
--
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