On 09/18/14 04:25, Richard Sandiford wrote:
This is the main patch for the bug. We should treat a register as invalid
for a mode change if simplify_subreg_regno cannot provide a new register
number for the result. We should treat a class as invalid for a mode change
if all registers in the class are invalid. This is an extension of the old
CANNOT_CHANGE_MODE_CLASS-based check (simplify_subreg_regno checks C_C_C_M).
I forgot to say that the patch is a prerequisite to removing aarch64's
C_C_C_M. There are other prerequisites too, but removing C_C_C_M without
this patch caused regressions in the existing testsuite, which is why no
new tests are needed.
gcc/
* hard-reg-set.h: Include hash-table.h.
(target_hard_regs): Add a finalize method and a x_simplifiable_subregs
field.
* target-globals.c (target_globals::~target_globals): Handle
hard_regs->finalize.
* rtl.h (subreg_shape): New structure.
(shape_of_subreg): New function.
(simplifiable_subregs): Declare.
* reginfo.c (simplifiable_subreg): New structure.
(simplifiable_subregs_hasher): Likewise.
(simplifiable_subregs): New function.
(invalid_mode_changes): Delete.
(alid_mode_changes, valid_mode_changes_obstack): New variables.
(record_subregs_of_mode): Remove subregs_of_mode parameter.
Record valid mode changes in valid_mode_changes.
(find_subregs_of_mode): Remove subregs_of_mode parameter.
Update calls to record_subregs_of_mode.
(init_subregs_of_mode): Remove invalid_mode_changes and bitmap
handling. Initialize new variables. Update call to
find_subregs_of_mode.
(invalid_mode_change_p): Check new variables instead of
invalid_mode_changes.
(finish_subregs_of_mode): Finalize new variables instead of
invalid_mode_changes.
(target_hard_regs::finalize): New function.
* ira-costs.c (print_allocno_costs): Call invalid_mode_change_p
even when CLASS_CANNOT_CHANGE_MODE is undefined.
Index: gcc/rtl.h
===================================================================
--- gcc/rtl.h 2014-09-15 11:55:40.459855161 +0100
+++ gcc/rtl.h 2014-09-15 12:26:21.249077760 +0100
+/* Return the shape of a SUBREG rtx. */
+
+static inline subreg_shape
+shape_of_subreg (const_rtx x)
+{
+ return subreg_shape (GET_MODE (SUBREG_REG (x)),
+ SUBREG_BYTE (x), GET_MODE (x));
+}
+
Is there some reason you don't have a constructor that accepts a
const_rtx?
OK for the trunk.
jeff
