My apologies again. My patch to simplify truncations of SUBREGs in
simplify-rtx.c contained an error where I'd accidentally compared
against a mode instead of the precision of that mode. Grr! It even
survived regression testing on two platforms. Fixed below, and
committed as obvious, after a full "make bootstrap" and "make -k check"
on x86_64-pc-linux-gnu with no new regressions.
2021-08-24 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
PR middle-end/102031
* simplify-rtx.c (simplify_truncation): When comparing precisions
use "subreg_prec" variable, not "subreg_mode".
{
unsigned int int_op_prec = GET_MODE_PRECISION (int_op_mode);
unsigned int subreg_prec = GET_MODE_PRECISION (subreg_mode);
- if (int_op_prec > subreg_mode)
+ if (int_op_prec > subreg_prec)
{
if (int_mode == subreg_mode)
return SUBREG_REG (op);
}
/* Simplification of (truncate:A (subreg:B X:C 0)) where
A is narrower than B and B is narrower than C. */
- else if (int_op_prec < subreg_mode
+ else if (int_op_prec < subreg_prec
&& GET_MODE_PRECISION (int_mode) < int_op_prec)
return simplify_gen_unary (TRUNCATE, int_mode,
SUBREG_REG (op), subreg_mode);