PA problem

[Richard Earnshaw]

Jeff, 

Whilst looking into a miscompilation we were seeing on the PA with 2.95.2, 
I spotted the following in the current sources:

In the PA machine description we currently have:

(define_insn ""
  [(set (match_operand:DF 0 "register_operand" "=f")
        (plus:DF (mult:DF (match_operand:DF 1 "register_operand" "f")
                          (match_operand:DF 2 "register_operand" "f"))
                 (match_operand:DF 3 "register_operand" "f")))
   (set (match_operand:DF 4 "register_operand" "=&f")
        (mult:DF (match_dup 1) (match_dup 2)))]
  "(! TARGET_SOFT_FLOAT && TARGET_PA_20
    && ! (reg_overlap_mentioned_p (operands[4], operands[1])
          || reg_overlap_mentioned_p (operands[4], operands[2])))"
  "#"
  [(set_attr "type" "fpmuldbl")
   (set_attr "length" "8")])


Shouldn't there also be a non-overlap of op[4] with op[3]?  After all, the 
splitter modifies op[4] in the first emitted instruction, but doesn't use 
op[3] until the second:

(define_split
  [(set (match_operand:DF 0 "register_operand" "=f")
        (plus:DF (mult:DF (match_operand:DF 1 "register_operand" "f")
                          (match_operand:DF 2 "register_operand" "f"))
                 (match_operand:DF 3 "register_operand" "f")))
   (set (match_operand:DF 4 "register_operand" "=&f")
        (mult:DF (match_dup 1) (match_dup 2)))]
  "! TARGET_SOFT_FLOAT && TARGET_PA_20"
  [(set (match_dup 4) (mult:DF (match_dup 1) (match_dup 2)))
   (set (match_dup 0) (plus:DF (mult:DF (match_dup 1) (match_dup 2))
                               (match_dup 3)))]
  "")

The patterns immediately after this example have a similar problem, I 
think. As do others in the description.

R.