Add new constraints to match whether a memory is not prefixed (em constraint)
or prefixed (ep constraint). This is one of 4 parts aimed at reworking the
vector extract code in patch V7 #6.
This patch just adds the new constraints, but these constraints will not be
used until the next patch. Originally I had just one constraint (em) that
matched non-prefixed memory operands. But in order to use it, I needed to make
sure the combiner did not combine vector extracts with a variable offset with a
PC-relative memory location.
I.e.:
#include <altivec.h>
static vector double vd;
double get (unsigned int n)
{
return vec_extract (vd, n);
}
In addition, as I contemplate the bigger issue about the insn length attribute,
I suspect we may need to have an ep attribute as well as em.
Patch V7 #6:
https://gcc.gnu.org/ml/gcc-patches/2019-11/msg01306.html
I have bootstrapped the compiler on a little endian power8 system and ran make
check and there were no regressions. Can I check this patch in?
2019-12-10 Michael Meissner <meiss...@linux.ibm.com>
* config/rs6000/constraints.md (em constraint): New constraint for
non-prefixed memory operands.
(ep constraint): New constraint for prefixed memory operands.
* config/rs6000/predicates.md (non_prefixed_memory): New predicate
for non-prefixed memory operands.
* doc/md.texi (PowerPC constraints): Document em and ep constraints.
Index: gcc/config/rs6000/constraints.md
===================================================================
--- gcc/config/rs6000/constraints.md (revision 279182)
+++ gcc/config/rs6000/constraints.md (working copy)
@@ -202,6 +202,16 @@ (define_constraint "H"
;; Memory constraints
+(define_memory_constraint "em"
+ "A memory operand that does not contain a prefixed address."
+ (and (match_code "mem")
+ (match_operand 0 "non_prefixed_memory")))
+
+(define_memory_constraint "ep"
+ "A memory operand that does contains a prefixed address."
+ (and (match_code "mem")
+ (match_operand 0 "prefixed_memory")))
+
(define_memory_constraint "es"
"A ``stable'' memory operand; that is, one which does not include any
automodification of the base register. Unlike @samp{m}, this constraint
Index: gcc/config/rs6000/predicates.md
===================================================================
--- gcc/config/rs6000/predicates.md (revision 279151)
+++ gcc/config/rs6000/predicates.md (working copy)
@@ -1846,3 +1846,17 @@ (define_predicate "prefixed_memory"
{
return address_is_prefixed (XEXP (op, 0), mode, NON_PREFIXED_DEFAULT);
})
+
+;; Return true if the operand is a valid memory address that does not use a
+;; prefixed address.
+(define_predicate "non_prefixed_memory"
+ (match_code "mem")
+{
+ enum insn_form iform
+ = address_to_insn_form (XEXP (op, 0), mode, NON_PREFIXED_DEFAULT);
+
+ return (iform != INSN_FORM_BAD
+ && iform != INSN_FORM_PREFIXED_NUMERIC
+ && iform != INSN_FORM_PCREL_LOCAL
+ && iform != INSN_FORM_PCREL_EXTERNAL);
+})
Index: gcc/doc/md.texi
===================================================================
--- gcc/doc/md.texi (revision 279182)
+++ gcc/doc/md.texi (working copy)
@@ -3373,6 +3373,12 @@ asm ("st %1,%0" : "=m<>" (mem) : "r" (va
is not.
+@item em
+A memory operand that does not contain a prefixed address.
+
+@item ep
+A memory operand that does contains a prefixed address.
+
@item es
A ``stable'' memory operand; that is, one which does not include any
automodification of the base register. This used to be useful when
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
