At the moment, define_cond_exec allows only a single substitution
pattern. That is
rather limiting if the target needs to clobber a scratch register in
order to compute the
required condition.
The attached patch allows to add clobber patterns after the main
pattern, and also adds
support for MATCH_SCRATCH in alter_predicate_for_insn.
This makes most sense together with the previous patch for MATCH_DUP support,
although the latter can also be used stand-alone, so have posted and
tested these
patches separately.
Bootstrapped on x86_64-pc-linux-gnu.
2020-12-12 Joern Rennecke <joern.renne...@embecosm.com>
Fix define_cond_exec flaw of not accepting clobbers.
* gensupport.c (alter_predicate_for_insn): Handle MATCH_SCRATCH.
(process_one_cond_exec): Allow extra patterns for clobbers.
diff --git a/gcc/gensupport.c b/gcc/gensupport.c
index e1ca06dbc1e..b472dc115b5 100644
--- a/gcc/gensupport.c
+++ b/gcc/gensupport.c
@@ -1198,8 +1198,11 @@ alter_predicate_for_insn (rtx pattern, int alt, int
max_op,
switch (code)
{
case MATCH_OPERAND:
+ case MATCH_SCRATCH:
{
- const char *c = XSTR (pattern, 2);
+ const char **altstr_loc
+ = &XSTR (pattern, code == MATCH_SCRATCH ? 1 : 2);
+ const char *c = *altstr_loc;
if (n_alternatives (c) != 1)
{
@@ -1216,19 +1219,22 @@ alter_predicate_for_insn (rtx pattern, int alt, int
max_op,
char *new_c = XNEWVEC (char, len);
memcpy (new_c, c, c_len);
+ char *wp = new_c + c_len;
+ if (*c == '=')
+ c++, c_len--;
for (i = 1; i < alt; ++i)
{
- new_c[i * (c_len + 1) - 1] = ',';
- memcpy (&new_c[i * (c_len + 1)], c, c_len);
+ *wp++ = ',';
+ memcpy (wp, c, c_len);
+ wp += c_len;
}
- new_c[len - 1] = '\0';
- XSTR (pattern, 2) = new_c;
+ *wp = '\0';
+ *altstr_loc = new_c;
}
}
/* Fall through. */
case MATCH_OPERATOR:
- case MATCH_SCRATCH:
case MATCH_PARALLEL:
XINT (pattern, 0) += max_op;
break;
@@ -1754,13 +1760,18 @@ process_one_cond_exec (class queue_elem *ce_elem)
collect_insn_data (insn_elem->data, &alternatives, &max_operand);
max_operand += 1;
- if (XVECLEN (ce_elem->data, 0) != 1)
+ for (i = XVECLEN (ce_elem->data, 0) - 1; i > 0; i--)
{
- error_at (ce_elem->loc, "too many patterns in predicate");
- return;
+ rtx part = XVECEXP (ce_elem->data, 0, i);
+ if (GET_CODE (part) != CLOBBER)
+ {
+ error_at (ce_elem->loc, "too many patterns in predicate");
+ return;
+ }
}
pred = copy_rtx (XVECEXP (ce_elem->data, 0, 0));
+ int n_clobbers = XVECLEN (ce_elem->data, 0) - 1;
pred = alter_predicate_for_insn (pred, alternatives, max_operand,
ce_elem->loc);
if (pred == NULL)
@@ -1774,8 +1785,15 @@ process_one_cond_exec (class queue_elem *ce_elem)
pattern = rtx_alloc (COND_EXEC);
XEXP (pattern, 0) = pred;
XEXP (pattern, 1) = add_implicit_parallel (XVEC (insn, 1));
- XVEC (insn, 1) = rtvec_alloc (1);
+ XVEC (insn, 1) = rtvec_alloc (1 + n_clobbers);
XVECEXP (insn, 1, 0) = pattern;
+ for (int i = n_clobbers; i > 0; i--)
+ {
+ rtx clobber = copy_rtx (XVECEXP (ce_elem->data, 0, i));
+ clobber = alter_predicate_for_insn (clobber, alternatives,
+ max_operand, ce_elem->loc);
+ XVECEXP (insn, 1, i) = clobber;
+ }
if (XVEC (ce_elem->data, 3) != NULL)
{
