On Wed, Apr 16, 2014 at 02:45:28PM -0600, Jeff Law wrote:
> Isn't the problem that operands 1 is a MEM which use the same register
> as operands 3 in the memory address?
Yes, exactly.
> ISTM either removing the memory constraint entirely, or splitting it off
> into a separate alternative and only earlyclobbering that alternative
> would be better.
>
> Or am I missing something?
No, that does seem better :-)
I tried both your suggestions; the first results in better code. Here's
a new patch. As before, it builds and fixes the testcase, but I didn't
run the testsuite (I have no emulator set up).
Thanks,
Segher
gcc/
PR target/60822
2014-04-16 Segher Boessenkool <seg...@kernel.crashing.org>
* config/m68k/m68k.md (extendplussidi): Don't allow memory for
operand 1.
---
gcc/config/m68k/m68k.md | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/gcc/config/m68k/m68k.md b/gcc/config/m68k/m68k.md
index e61048b..57ba1a1 100644
--- a/gcc/config/m68k/m68k.md
+++ b/gcc/config/m68k/m68k.md
@@ -1868,9 +1868,12 @@ (define_insn "extendsidi2"
;; Maybe there is a way to make that the general case, by forcing the
;; result of the SI tree to be in the lower register of the DI target
+;; Don't allow two memory operands: it needs an earlyclobber and will
+;; result in worse code.
+
(define_insn "extendplussidi"
[(set (match_operand:DI 0 "register_operand" "=d")
- (sign_extend:DI (plus:SI (match_operand:SI 1 "general_operand" "%rmn")
+ (sign_extend:DI (plus:SI (match_operand:SI 1 "nonmemory_operand" "%rn")
(match_operand:SI 2 "general_operand" "rmn"))))]
""
{
--
1.8.1.4
