> I suggest making reload reload the PSImode subreg instead, and
> make the m32c machine description provide for a tertiary
> reload so that the value can be loaded & truncated.
Don't know how to set up a tertiary reload (it's not documented
anywhere).
Is this the type of patch you're thining about? It seems to compile
that problem case, but I haven't tried anything else yet.
Index: config/m32c/m32c.c
===================================================================
--- config/m32c/m32c.c (revision 146617)
+++ config/m32c/m32c.c (working copy)
@@ -2040,12 +2040,37 @@ m32c_legitimize_reload_address (rtx * x,
push_reload (XEXP (*x, 0), NULL_RTX, &XEXP (*x, 0), NULL,
A_REGS, Pmode, VOIDmode, 0, 0, opnum,
type);
return 1;
}
+ /* If we see an RTX like (subreg:PSI (reg:SI ...)) we need to reload
+ the subreg. We need to check for PLUS and non-PLUS cases. */
+
+ if (GET_CODE (*x) == SUBREG
+ && GET_MODE (XEXP (*x, 0)) == SImode)
+ {
+ if (type == RELOAD_OTHER)
+ type = RELOAD_FOR_OTHER_ADDRESS;
+ push_reload (*x, NULL_RTX, x, NULL,
+ A_REGS, Pmode, VOIDmode, 0, 0, opnum,
+ type);
+ return 1;
+ }
+ if (GET_CODE (*x) == PLUS
+ && GET_CODE (XEXP (*x, 0)) == SUBREG
+ && GET_MODE (XEXP (XEXP (*x, 0), 0)) == SImode)
+ {
+ if (type == RELOAD_OTHER)
+ type = RELOAD_FOR_OTHER_ADDRESS;
+ push_reload (XEXP (*x, 0), NULL_RTX, &(XEXP (*x, 0)), NULL,
+ A_REGS, Pmode, VOIDmode, 0, 0, opnum,
+ type);
+ return 1;
+ }
+
return 0;
}
/* Implements LEGITIMATE_CONSTANT_P. We split large constants anyway,
so we can allow anything. */
int
