[15/23] recog: Add a validate_change_xveclen function
Richard Sandiford
richard.sandiford@arm.com
Fri Nov 13 08:19:15 GMT 2020
A later patch wants to be able to use the validate_change machinery
to reduce the XVECLEN of a PARALLEL. This should be more efficient
than allocating a separate PARALLEL at a possibly distant memory
location, especially since the new PARALLEL would be garbage rtl if
the new pattern turns out not to match. Combine already pulls this
trick with SUBST_INT.
This patch adds a general helper for doing that.
gcc/
* recog.h (validate_change_xveclen): Declare.
* recog.c (change_t::old_len): New field.
(validate_change_1): Add a new_len parameter. Conditionally
replace the XVECLEN of an rtx, avoiding single-element PARALLELs.
(validate_change_xveclen): New function.
(cancel_changes): Undo changes made by validate_change_xveclen.
---
gcc/recog.c | 41 +++++++++++++++++++++++++++++++++++------
gcc/recog.h | 1 +
2 files changed, 36 insertions(+), 6 deletions(-)
diff --git a/gcc/recog.c b/gcc/recog.c
index 2d934169a81..65125b8f0d1 100644
--- a/gcc/recog.c
+++ b/gcc/recog.c
@@ -183,6 +183,7 @@ struct change_t
{
rtx object;
int old_code;
+ int old_len;
bool unshare;
rtx *loc;
rtx old;
@@ -194,8 +195,10 @@ static int changes_allocated;
static int num_changes = 0;
/* Validate a proposed change to OBJECT. LOC is the location in the rtl
- at which NEW_RTX will be placed. If OBJECT is zero, no validation is done,
- the change is simply made.
+ at which NEW_RTX will be placed. If NEW_LEN is >= 0, XVECLEN (NEW_RTX, 0)
+ will also be changed to NEW_LEN, which is no greater than the current
+ XVECLEN. If OBJECT is zero, no validation is done, the change is
+ simply made.
Two types of objects are supported: If OBJECT is a MEM, memory_address_p
will be called with the address and mode as parameters. If OBJECT is
@@ -212,14 +215,25 @@ static int num_changes = 0;
Otherwise, perform the change and return 1. */
static bool
-validate_change_1 (rtx object, rtx *loc, rtx new_rtx, bool in_group, bool unshare)
+validate_change_1 (rtx object, rtx *loc, rtx new_rtx, bool in_group,
+ bool unshare, int new_len = -1)
{
rtx old = *loc;
- if (old == new_rtx || rtx_equal_p (old, new_rtx))
+ /* Single-element parallels aren't valid and won't match anything.
+ Replace them with the single element. */
+ if (new_len == 1 && GET_CODE (new_rtx) == PARALLEL)
+ {
+ new_rtx = XVECEXP (new_rtx, 0, 0);
+ new_len = -1;
+ }
+
+ if ((old == new_rtx || rtx_equal_p (old, new_rtx))
+ && (new_len < 0 || XVECLEN (new_rtx, 0) == new_len))
return 1;
- gcc_assert (in_group != 0 || num_changes == 0);
+ gcc_assert ((in_group != 0 || num_changes == 0)
+ && (new_len < 0 || new_rtx == *loc));
*loc = new_rtx;
@@ -239,8 +253,12 @@ validate_change_1 (rtx object, rtx *loc, rtx new_rtx, bool in_group, bool unshar
changes[num_changes].object = object;
changes[num_changes].loc = loc;
changes[num_changes].old = old;
+ changes[num_changes].old_len = (new_len >= 0 ? XVECLEN (new_rtx, 0) : -1);
changes[num_changes].unshare = unshare;
+ if (new_len >= 0)
+ XVECLEN (new_rtx, 0) = new_len;
+
if (object && !MEM_P (object))
{
/* Set INSN_CODE to force rerecognition of insn. Save old code in
@@ -278,6 +296,14 @@ validate_unshare_change (rtx object, rtx *loc, rtx new_rtx, bool in_group)
return validate_change_1 (object, loc, new_rtx, in_group, true);
}
+/* Change XVECLEN (*LOC, 0) to NEW_LEN. OBJECT, IN_GROUP and the return
+ value are as for validate_change_1. */
+
+bool
+validate_change_xveclen (rtx object, rtx *loc, int new_len, bool in_group)
+{
+ return validate_change_1 (object, loc, *loc, in_group, false, new_len);
+}
/* Keep X canonicalized if some changes have made it non-canonical; only
modifies the operands of X, not (for example) its code. Simplifications
@@ -541,7 +567,10 @@ cancel_changes (int num)
they were made. */
for (i = num_changes - 1; i >= num; i--)
{
- *changes[i].loc = changes[i].old;
+ if (changes[i].old_len >= 0)
+ XVECLEN (*changes[i].loc, 0) = changes[i].old_len;
+ else
+ *changes[i].loc = changes[i].old;
if (changes[i].object && !MEM_P (changes[i].object))
INSN_CODE (changes[i].object) = changes[i].old_code;
}
diff --git a/gcc/recog.h b/gcc/recog.h
index d87456c257f..e152e2bb591 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -88,6 +88,7 @@ extern int check_asm_operands (rtx);
extern int asm_operand_ok (rtx, const char *, const char **);
extern bool validate_change (rtx, rtx *, rtx, bool);
extern bool validate_unshare_change (rtx, rtx *, rtx, bool);
+extern bool validate_change_xveclen (rtx, rtx *, int, bool);
extern bool canonicalize_change_group (rtx_insn *insn, rtx x);
extern int insn_invalid_p (rtx_insn *, bool);
extern int verify_changes (int);
--
2.17.1
More information about the Gcc-patches
mailing list