From: Jeff Law Date: Sun, 21 Feb 1993 18:10:37 +0000 (-0700) Subject: * pa.md (load high pattern): Rework constraints to reduce %r1 spillage. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e53bfc4bb645c747242a8d5d51960acc7b509946;p=gcc.git * pa.md (load high pattern): Rework constraints to reduce %r1 spillage. From-SVN: r3510 --- diff --git a/gcc/config/pa/pa.md b/gcc/config/pa/pa.md index d780323c222..39d78344286 100644 --- a/gcc/config/pa/pa.md +++ b/gcc/config/pa/pa.md @@ -934,8 +934,20 @@ ;; For all symbolic operands *except* function addresses and read-only ;; operands (which live in TEXT space and do not require relocation). +;; +;; The constraints are a little strange. +;; The basic idea is to prefer %r1 as much as possible for register +;; allocation (hence we do not allow regclass to know about the general +;; register case (via *r). +;; We also want to avoid spilling %r1 as that will cause every use +;; of %r1 to be reloaded, so we make the %r1 case very expensive +;; as far as reload is concerned (via !a). +;; +;; The real solution is to not spill all pseudos allocated to %r1 +;; when %r1 is needed as a spill register, but that is considerably +;; more difficult than coercing decent behavior via constraints. (define_insn "" - [(set (match_operand:SI 0 "register_operand" "=a,!*r") + [(set (match_operand:SI 0 "register_operand" "=!a,*r") (high:SI (match_operand 1 "" "")))] "! TARGET_KERNEL && symbolic_operand(operands[1], Pmode) && ! function_label_operand (operands[1])