Turn CANNOT_CHANGE_MODE_CLASS into a hook

This also seemed like a good opportunity to reverse the sense of the
hook to "can", to avoid the awkward double negative in !CANNOT.

2017-09-15  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayard  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* target.def (can_change_mode_class): New hook.
	(mode_rep_extended): Refer to it instead of CANNOT_CHANGE_MODE_CLASS.
	(hard_regno_nregs): Likewise.
	* hooks.h (hook_bool_mode_mode_reg_class_t_true): Declare.
	* hooks.c (hook_bool_mode_mode_reg_class_t_true): New function.
	* doc/tm.texi.in (CANNOT_CHANGE_MODE_CLASS): Replace with...
	(TARGET_CAN_CHANGE_MODE_CLASS): ...this.
	(LOAD_EXTEND_OP): Update accordingly.
	* doc/tm.texi: Regenerate.
	* doc/rtl.texi: Refer to TARGET_CAN_CHANGE_MODE_CLASS instead of
	CANNOT_CHANGE_MODE_CLASS.
	* hard-reg-set.h (REG_CANNOT_CHANGE_MODE_P): Replace with...
	(REG_CAN_CHANGE_MODE_P): ...this new macro.
	* combine.c (simplify_set): Update accordingly.
	* emit-rtl.c (validate_subreg): Likewise.
	* recog.c (general_operand): Likewise.
	* regcprop.c (mode_change_ok): Likewise.
	* reload1.c (choose_reload_regs): Likewise.
	(inherit_piecemeal_p): Likewise.
	* rtlanal.c (simplify_subreg_regno): Likewise.
	* postreload.c (reload_cse_simplify_set): Use REG_CAN_CHANGE_MODE_P
	instead of CANNOT_CHANGE_MODE_CLASS.
	(reload_cse_simplify_operands): Likewise.
	* reload.c (push_reload): Use targetm.can_change_mode_class
	instead of CANNOT_CHANGE_MODE_CLASS.
	(push_reload): Likewise.  Also use REG_CAN_CHANGE_MODE_P instead of
	REG_CANNOT_CHANGE_MODE_P.
	* config/alpha/alpha.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/alpha/alpha.c (alpha_can_change_mode_class): New function.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/arm/arm.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/arm/arm.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(arm_can_change_mode_class): New function.
	* config/arm/neon.md: Refer to TARGET_CAN_CHANGE_MODE_CLASS rather
	than CANNOT_CHANGE_MODE_CLASS in comments.
	* config/i386/i386.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/i386/i386-protos.h (ix86_cannot_change_mode_class): Delete.
	* config/i386/i386.c (ix86_cannot_change_mode_class): Replace with...
	(ix86_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/ia64/ia64.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/ia64/ia64.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(ia64_can_change_mode_class): New function.
	* config/m32c/m32c.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/m32c/m32c-protos.h (m32c_cannot_change_mode_class): Delete.
	* config/m32c/m32c.c (m32c_cannot_change_mode_class): Replace with...
	(m32c_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/mips/mips.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/mips/mips-protos.h (mips_cannot_change_mode_class): Delete.
	* config/mips/mips.c (mips_cannot_change_mode_class): Replace with...
	(mips_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/msp430/msp430.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/msp430/msp430.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(msp430_can_change_mode_class): New function.
	* config/nvptx/nvptx.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/nvptx/nvptx.c (nvptx_can_change_mode_class): New function.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/pa/pa32-regs.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/pa/pa64-regs.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/pa/pa-protos.h (pa_cannot_change_mode_class): Delete.
	* config/pa/pa.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(pa_cannot_change_mode_class): Replace with...
	(pa_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(pa_modes_tieable_p): Refer to TARGET_CAN_CHANGE_MODE_CLASS rather
	than CANNOT_CHANGE_MODE_CLASS in comments.
	* config/pdp11/pdp11.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/pdp11/pdp11-protos.h (pdp11_cannot_change_mode_class): Delete.
	* config/pdp11/pdp11.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(pdp11_cannot_change_mode_class): Replace with...
	(pdp11_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	* config/powerpcspe/powerpcspe.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/powerpcspe/powerpcspe-protos.h
	(rs6000_cannot_change_mode_class_ptr): Delete.
	* config/powerpcspe/powerpcspe.c
	(rs6000_cannot_change_mode_class_ptr): Delete.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(rs6000_option_override_internal): Assign to
	targetm.can_change_mode_class instead of
	rs6000_cannot_change_mode_class_ptr.
	(rs6000_cannot_change_mode_class): Replace with...
	(rs6000_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(rs6000_debug_cannot_change_mode_class): Replace with...
	(rs6000_debug_can_change_mode_class): ...this new function.
	* config/riscv/riscv.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/riscv/riscv.c (riscv_can_change_mode_class): New function.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/rs6000/rs6000.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/rs6000/rs6000-protos.h (rs6000_cannot_change_mode_class_ptr):
	Delete.
	* config/rs6000/rs6000.c (rs6000_cannot_change_mode_class_ptr): Delete.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(rs6000_option_override_internal): Assign to
	targetm.can_change_mode_class instead of
	rs6000_cannot_change_mode_class_ptr.
	(rs6000_cannot_change_mode_class): Replace with...
	(rs6000_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(rs6000_debug_cannot_change_mode_class): Replace with...
	(rs6000_debug_can_change_mode_class): ...this new function.
	* config/s390/s390.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/s390/s390-protos.h (s390_cannot_change_mode_class): Delete.
	* config/s390/s390.c (s390_cannot_change_mode_class): Replace with...
	(s390_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/sh/sh.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/sh/sh-protos.h (sh_cannot_change_mode_class): Delete.
	* config/sh/sh.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(sh_cannot_change_mode_class): Replace with...
	(sh_can_change_mode_class): ...this new function, inverting the
	sense of the return value.
	* config/sparc/sparc.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/sparc/sparc.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(sparc_can_change_mode_class): New function.
	* config/spu/spu.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/spu/spu.c (spu_can_change_mode_class): New function.
	(TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	* config/visium/visium.h (CANNOT_CHANGE_MODE_CLASS): Delete.
	* config/visium/visium.c (TARGET_CAN_CHANGE_MODE_CLASS): Redefine.
	(visium_can_change_mode_class): New function.
	* system.h (CANNOT_CHANGE_MODE_CLASS): Poison.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r252816

4 files changed, 16 insertions, 25 deletions

diff --git a/gcc/config/pa/pa-protos.h b/gcc/config/pa/pa-protos.h
index ba496f9..cbf25af 100644
--- a/gcc/config/pa/pa-protos.h
+++ b/gcc/config/pa/pa-protos.h
@@ -106,8 +106,6 @@ extern void pa_asm_output_aligned_local (FILE *, const char *,
 					 unsigned HOST_WIDE_INT,
 					 unsigned int);
 extern void pa_hpux_asm_output_external (FILE *, tree, const char *);
-extern bool pa_cannot_change_mode_class (machine_mode, machine_mode,
-					 enum reg_class);
 extern HOST_WIDE_INT pa_initial_elimination_offset (int, int);
 
 extern const int pa_magic_milli[];
diff --git a/gcc/config/pa/pa.c b/gcc/config/pa/pa.c
index f39b672..651ae59 100644
--- a/gcc/config/pa/pa.c
+++ b/gcc/config/pa/pa.c
@@ -204,6 +204,7 @@ static bool pa_callee_copies (cumulative_args_t, machine_mode,
 static unsigned int pa_hard_regno_nregs (unsigned int, machine_mode);
 static bool pa_hard_regno_mode_ok (unsigned int, machine_mode);
 static bool pa_modes_tieable_p (machine_mode, machine_mode);
+static bool pa_can_change_mode_class (machine_mode, machine_mode, reg_class_t);
 
 /* The following extra sections are only used for SOM.  */
 static GTY(()) section *som_readonly_data_section;
@@ -421,6 +422,9 @@ static size_t n_deferred_plabels = 0;
 #undef TARGET_MODES_TIEABLE_P
 #define TARGET_MODES_TIEABLE_P pa_modes_tieable_p
 
+#undef TARGET_CAN_CHANGE_MODE_CLASS
+#define TARGET_CAN_CHANGE_MODE_CLASS pa_can_change_mode_class
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 /* Parse the -mfixed-range= option string.  */
@@ -10001,27 +10005,26 @@ pa_hpux_file_end (void)
 }
 #endif
 
-/* Return true if a change from mode FROM to mode TO for a register
-   in register class RCLASS is invalid.  */
+/* Implement TARGET_CAN_CHANGE_MODE_CLASS.  */
 
-bool
-pa_cannot_change_mode_class (machine_mode from, machine_mode to,
-			     enum reg_class rclass)
+static bool
+pa_can_change_mode_class (machine_mode from, machine_mode to,
+			  reg_class_t rclass)
 {
   if (from == to)
-    return false;
+    return true;
 
   if (GET_MODE_SIZE (from) == GET_MODE_SIZE (to))
-    return false;
+    return true;
 
   /* Reject changes to/from modes with zero size.  */
   if (!GET_MODE_SIZE (from) || !GET_MODE_SIZE (to))
-    return true;
+    return false;
 
   /* Reject changes to/from complex and vector modes.  */
   if (COMPLEX_MODE_P (from) || VECTOR_MODE_P (from)
       || COMPLEX_MODE_P (to) || VECTOR_MODE_P (to))
-    return true;
+    return false;
       
   /* There is no way to load QImode or HImode values directly from memory
      to a FP register.  SImode loads to the FP registers are not zero
@@ -10029,16 +10032,16 @@ pa_cannot_change_mode_class (machine_mode from, machine_mode to,
      of LOAD_EXTEND_OP.  Thus, we can't allow changing between modes with
      different sizes in the floating-point registers.  */
   if (MAYBE_FP_REG_CLASS_P (rclass))
-    return true;
+    return false;
 
   /* TARGET_HARD_REGNO_MODE_OK places modes with sizes larger than a word
      in specific sets of registers.  Thus, we cannot allow changing
      to a larger mode when it's larger than a word.  */
   if (GET_MODE_SIZE (to) > UNITS_PER_WORD
       && GET_MODE_SIZE (to) > GET_MODE_SIZE (from))
-    return true;
+    return false;
 
-  return false;
+  return true;
 }
 
 /* Implement TARGET_MODES_TIEABLE_P.
@@ -10047,7 +10050,7 @@ pa_cannot_change_mode_class (machine_mode from, machine_mode to,
    are not ok in the floating-point registers.  However, this prevents
    tieing these modes to SImode and DImode in the general registers.
    So, this isn't a good idea.  We rely on TARGET_HARD_REGNO_MODE_OK and
-   CANNOT_CHANGE_MODE_CLASS to prevent these modes from being used
+   TARGET_CAN_CHANGE_MODE_CLASS to prevent these modes from being used
    in the floating-point registers.  */
 
 static bool
diff --git a/gcc/config/pa/pa32-regs.h b/gcc/config/pa/pa32-regs.h
index f168ecf..d479b1a 100644
--- a/gcc/config/pa/pa32-regs.h
+++ b/gcc/config/pa/pa32-regs.h
@@ -294,11 +294,6 @@ enum reg_class { NO_REGS, R1_REGS, GENERAL_REGS, FPUPPER_REGS, FP_REGS,
   {0x00000000, 0x00000000, 0x01000000},	/* SHIFT_REGS */		\
   {0xfffffffe, 0xffffffff, 0x03ffffff}}	/* ALL_REGS */
 
-/* Defines invalid mode changes.  */
-
-#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \
-  pa_cannot_change_mode_class (FROM, TO, CLASS)
-
 /* Return the class number of the smallest class containing
    reg number REGNO.  This could be a conditional expression
    or could index an array.  */
diff --git a/gcc/config/pa/pa64-regs.h b/gcc/config/pa/pa64-regs.h
index 15b8808..d9c8dd4 100644
--- a/gcc/config/pa/pa64-regs.h
+++ b/gcc/config/pa/pa64-regs.h
@@ -230,11 +230,6 @@ enum reg_class { NO_REGS, R1_REGS, GENERAL_REGS, FPUPPER_REGS, FP_REGS,
   {0x00000000, 0x10000000},	/* SHIFT_REGS */		\
   {0xfffffffe, 0x3fffffff}}	/* ALL_REGS */
 
-/* Defines invalid mode changes.  */
-
-#define CANNOT_CHANGE_MODE_CLASS(FROM, TO, CLASS) \
-  pa_cannot_change_mode_class (FROM, TO, CLASS)
-
 /* Return the class number of the smallest class containing
    reg number REGNO.  This could be a conditional expression
    or could index an array.  */