The MOVC3 machine instruction has `memmove' semantics[1]:
"The operation of the instruction is such that overlap of the source and
destination strings does not affect the result."
so use it to provide the `movmemhi' instruction as well.
References:
[1] DEC STD 032-0 "VAX Architecture Standard", Digital Equipment
Corporation, A-DS-EL-00032-00-0 Rev J, December 15, 1989, Section
3.10 "Character-String Instructions", p. 3-162
gcc/
* config/vax/vax.md (cpymemhi1): Rename insn to...
(movmemhi1): ... this.
(cpymemhi): Update accordingly. Remove constraints.
(movmemhi): New expander.
gcc/testsuite/
* gcc.target/vax/movmem.c: New test.
---
gcc/config/vax/vax.md | 24 ++++++++++++++++++------
gcc/testsuite/gcc.target/vax/movmem.c | 23 +++++++++++++++++++++++
2 files changed, 41 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/vax/movmem.c
diff --git a/gcc/config/vax/vax.md b/gcc/config/vax/vax.md
index 66f03df1932..f8e1c2eb02b 100644
--- a/gcc/config/vax/vax.md
+++ b/gcc/config/vax/vax.md
@@ -206,16 +206,28 @@ (define_insn "movstrictqi"
}")
;; This is here to accept 4 arguments and pass the first 3 along
-;; to the cpymemhi1 pattern that really does the work.
+;; to the movmemhi1 pattern that really does the work.
(define_expand "cpymemhi"
- [(set (match_operand:BLK 0 "general_operand" "=g")
- (match_operand:BLK 1 "general_operand" "g"))
- (use (match_operand:HI 2 "general_operand" "g"))
+ [(set (match_operand:BLK 0 "memory_operand" "")
+ (match_operand:BLK 1 "memory_operand" ""))
+ (use (match_operand:HI 2 "general_operand" ""))
+ (match_operand 3 "" "")]
+ ""
+ "
+{
+ emit_insn (gen_movmemhi1 (operands[0], operands[1], operands[2]));
+ DONE;
+}")
+
+(define_expand "movmemhi"
+ [(set (match_operand:BLK 0 "memory_operand" "")
+ (match_operand:BLK 1 "memory_operand" ""))
+ (use (match_operand:HI 2 "general_operand" ""))
(match_operand 3 "" "")]
""
"
{
- emit_insn (gen_cpymemhi1 (operands[0], operands[1], operands[2]));
+ emit_insn (gen_movmemhi1 (operands[0], operands[1], operands[2]));
DONE;
}")
@@ -224,7 +236,7 @@ (define_expand "cpymemhi"
;; that anything generated as this insn will be recognized as one
;; and that it won't successfully combine with anything.
-(define_insn "cpymemhi1"
+(define_insn "movmemhi1"
[(set (match_operand:BLK 0 "memory_operand" "=o")
(match_operand:BLK 1 "memory_operand" "o"))
(use (match_operand:HI 2 "general_operand" "g"))
diff --git a/gcc/testsuite/gcc.target/vax/movmem.c
b/gcc/testsuite/gcc.target/vax/movmem.c
new file mode 100644
index 00000000000..b907d8a376d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/vax/movmem.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+
+#include <stddef.h>
+
+void *
+memmove8 (void *to, const void *from, size_t size)
+{
+ unsigned char s8 = size;
+ return __builtin_memmove (to, from, s8);
+}
+
+/* Expect assembly like:
+
+ movl 4(%ap),%r6
+ movzbl 12(%ap),%r7
+ movl 8(%ap),%r8
+ movc3 %r7,(%r8),(%r6)
+ movl %r6,%r0
+
+ */
+
+/* { dg-final { scan-assembler "\tmovc3 " } } */
--
2.11.0
