+2014-05-20 Nick Clifton <nickc@redhat.com>
+
+ * config/msp430/msp430.md (zero_extendpsisi2): Use + constraint on
+ operand 0 in order to prevent confusion about the number of
+ registers involved.
+
2014-05-20 Richard Biener <rguenther@suse.de>
PR tree-optimization/61221
; when the PSI value is negative..
;
; Note: using PUSHM.A #1 is two bytes smaller than using PUSHX.A....
+;
+; Note: We use a + constraint on operand 0 as otherwise GCC gets confused
+; about extending a single PSI mode register into a pair of SImode registers
+; with the same starting register. It thinks that the upper register of
+; the pair is unused and so it can clobber it. Try compiling 20050826-2.c
+; at -O2 to see this.
(define_insn "zero_extendpsisi2"
- [(set (match_operand:SI 0 "register_operand" "=r")
+ [(set (match_operand:SI 0 "register_operand" "+r")
(zero_extend:SI (match_operand:PSI 1 "register_operand" "r")))]
""
"*